Ceramides are central intermediates of sphingolipid metabolism, a family of fatty molecules that form membranes and act as signaling compounds. In mammals, elevated ceramide levels are closely associated with insulin resistance and type 2 diabetes, but the relationship is complicated by the fact that ceramides come in many molecular species with different fatty-acid chain lengths. Ceramide synthases, the enzymes that build ceramides, therefore sit at a critical control point. Unusually, several members of the ceramide synthase family carry a conserved homeodomain, a DNA-binding module best known from transcription factors, whose metabolic role has remained poorly understood.

The fruit fly offers a clean experimental system for probing this puzzle. Drosophila melanogaster possesses only one ceramide synthase gene, schlank, whose protein contains the catalytic Lag1p motif required for ceramide production as well as two predicted nuclear localization sequences, NLS1 and NLS2, embedded within the homeodomain region. Because there is just one enzyme rather than a family of six as in mammals, any change in its sequence can be interpreted without worrying about redundancy between related proteins masking the effect.

To test what each region does, the team used genome engineering to create knock-in flies carrying precise point mutations in the endogenous schlank gene. Two variants took center stage: KINLS1, which disrupts the first nuclear localization sequence, and KIE118A, which replaces a glutamic acid at position 118 with alanine. Under normal dietary conditions both mutants looked deceptively healthy. They retained DNA binding and the transcriptional repression activity characteristic of the wild-type protein, suggesting that the homeodomain’s day job was still being performed.

The picture changed dramatically when the flies were challenged with a high-sugar diet. Both knock-in lines became markedly more vulnerable to diet-induced metabolic dysfunction, developing enhanced hyperglycemia and showing impaired recruitment of tGPH, a fluorescent reporter used to visualize insulin signaling at the cell membrane. In other words, mutations that left the enzyme’s basal functions intact still compromised the animal’s ability to cope with sugar excess, revealing that the homeodomain contributes to metabolic stress tolerance in ways invisible under standard conditions.

The KIE118A mutant displayed additional defects that pointed to a breakdown in hormonal communication. These flies showed increased nuclear localization of FoxO, a transcription factor that acts as a readout of reduced insulin signaling, and retention of DILP2, one of the fly’s insulin-like peptides, inside the insulin-producing cells of the brain. Normally these cells release DILP2 into circulation to coordinate glucose handling across the body; its accumulation within the secreting cells suggests a failure in the release machinery or in the feedback loops that normally prompt secretion.

Remarkably, the direction of the effect could be reversed depending on which part of the protein was altered and where it was expressed. When the researchers used tissue-specific allele-switching to replace the fat body’s endogenous Schlank with a DNA-binding-deficient NLS2 variant or a catalytically inactive H215D variant, selected high-sugar-diet phenotypes were partially attenuated rather than worsened. FoxO nuclear accumulation and DILP2 retention both improved in these animals. However, the rescue was incomplete: hyperglycemia and reduced body weight persisted, indicating that the fat body is one node in a larger network rather than the sole site of action.

Lipidomic analysis by mass spectrometry uncovered the biochemical substrate of these effects. The sphingolipid profile of the flies underwent extensive remodeling in a diet-dependent manner, and the two fat-body variants, NLS2 and H215D, caused a marked reduction of the fat-body ceramide pool. This depletion extended across ceramide species containing the d14:1/20:0 and d14:1/22:0 fatty-acid combinations, as well as ceramide phosphoethanolamine and hexosylceramide, the sphingolipid classes that dominate insect membranes. The data link specific ceramide species, not just total ceramide mass, to the insulin phenotypes.

The study’s central conclusion is that the Schlank homeodomain regulates insulin homeostasis in a site- and tissue-dependent manner. Disrupting the nuclear localization sequence NLS1 or the conserved glutamate at position 118 increases susceptibility to diet-induced insulin resistance, while swapping in DNA-binding-deficient or catalytically inactive variants specifically in the fat body can partially shield the animal from some of the same phenotypes. The authors propose a model in which insulin signaling, inter-organ communication between the brain’s insulin-producing cells and the fat body, and the composition of the sphingolipid pool jointly determine metabolic outcome.

For researchers working on human metabolic disease, the implications are tantalizing. Mammalian ceramide synthases also carry homeodomain-like regions, and if a comparable nuclear function exists in human cells, it could represent an unexploited regulatory axis connecting lipid metabolism, gene expression and insulin sensitivity. The fly work cannot yet prescribe therapies, but it demonstrates with unusual clarity that the same enzyme can push metabolism toward resistance or toward resilience depending on which of its molecular addresses is altered, and that the fat body, the insect analog of adipose tissue and liver, is a decisive arena in which ceramide chemistry and insulin biology meet.

Subject of Research: How homeodomain sites of the Drosophila ceramide synthase Schlank differentially regulate diet-induced insulin resistance and sphingolipid metabolism

Article Title: Drosophila CerS homeodomain sites differentially alter insulin resistance

Article References: Vera-Granda, C., Sociale, M., Beckschäfer, K., Kanevskij, I., Gerding, M., Eckardt, F., Rindsfüsser, H., Thiele, C., Ziegler, A. B., Bülow, M. H., & Bauer, R. (2026). Drosophila CerS homeodomain sites differentially alter insulin resistance. BMC Biology. https://doi.org/10.1186/s12915-026-02763-9

Image Credits: AI Generated

DOI: 10.1186/s12915-026-02763-9

Keywords: ceramide synthase, sphingolipids, insulin resistance, Drosophila melanogaster, homeodomain, high-sugar diet, fat body, DILP2, FoxO, lipidomics, type 2 diabetes, BMC Biology

Zygotic genome activation, commonly abbreviated ZGA, is the moment when a newly fertilized egg stops relying on the maternal RNA stockpiled inside the oocyte and begins transcribing its own genes at scale. In mice, this transition culminates during the 2-cell stage, with what researchers call major ZGA occurring in late 2-cell embryos. It is a famously fragile period. A large fraction of embryos cultured in vitro stall at exactly this point, failing to complete the switch from maternal to embryonic control. That developmental arrest is one of the central bottlenecks for assisted reproductive technologies, or ART, and any intervention that eases the passage through ZGA has direct clinical relevance.

The researchers began by comparing mouse embryos cultured under hypoxic conditions with those grown in normal atmospheric oxygen, and with embryos developing in vivo. The results were clear: hypoxic culture improved blastocyst formation and reduced developmental arrest during the ZGA window. When the team profiled gene expression in late 2-cell embryos, they found that the zygotic transcriptome of hypoxia-cultured embryos closely mimicked the patterns seen in physiologically developing, in vivo embryos during major ZGA. In other words, low oxygen did not merely push embryos along; it steered their gene expression toward a more natural trajectory, blunting the artificial signature that in vitro culture typically imprints on the embryonic genome.

To understand how oxygen levels could exert such an influence, the investigators turned their attention to histone modifications, the chemical tags that decorate the protein spools around which DNA is wound. Their focus fell on H3K4me3, the trimethylation of histone H3 at lysine 4, a mark long associated with active and poised promoters. Using CUT&Tag, a sensitive technique for mapping chromatin marks in scarce samples, the team compared H3K4me3 landscapes between hypoxia- and normoxia-cultured late 2-cell embryos. The comparison revealed a striking redistribution. Under hypoxia, H3K4me3 became specifically enriched at the promoters of zygotic genes, while it decreased at transposable elements and at oocyte-specific genomic domains.

That redistribution matters because it tracks precisely with what an embryo needs at this stage. Zygotic genes must be switched on, while the transcription of transposable elements and lingering oocyte programs must be restrained. The elevated H3K4me3 at zygotic promoters under hypoxia was not an isolated observation; the team showed that higher expression deciles of genes corresponded to progressively higher H3K4me3 levels, confirming the expected positive correlation between this mark and transcriptional output. Genes that were upregulated under hypoxia showed enhanced H3K4me3 around their transcription start sites, and genome browser views at representative loci such as Kank2 and Grb2 illustrated the pattern directly.

The mechanistic story deepened when the researchers examined how H3K4me3 related to chromatin accessibility and the machinery of transcription itself. Regions of the genome that were chromatin-accessible, regions enriched for RNA polymerase II, and regions enriched for the Ser2-phosphorylated form of RNA polymerase II, known as Ser2P, all exhibited higher H3K4me3 enrichment in hypoxia-cultured late 2-cell embryos. Ser2 phosphorylation is a critical modification of the polymerase’s C-terminal domain that marks the elongation phase of transcription, when RNA synthesis is actively proceeding along the gene body. The co-localization of the histone mark with these polymerase states suggested that H3K4me3 under hypoxia was not just a passive correlate of activity but was functionally entwined with both the initiation and the elongation of zygotic transcripts.

Direct measurements supported that interpretation. Global levels of RNA polymerase II and of its Ser2-phosphorylated form were both increased under hypoxia, and the polymerase was recruited to the very regions that had gained H3K4me3, initiating transcription and driving elongation there. Immunofluorescence imaging of 5-EU incorporation, which labels newly synthesized RNA, showed that transcriptional activity in hypoxia-cultured embryos matched that of in vivo embryos at the late 2-cell stage, reinforcing the physiological fidelity of the hypoxic culture condition. At key ZGA loci including Obox3, Klf17, Ep300 and L3mbtl2, the team observed the H3K4me3 and polymerase signals converging on the genes that define the embryonic program.

Perhaps the most compelling piece of evidence came from a pharmacological experiment. The researchers treated embryos with CPI-455, an inhibitor of the lysine demethylases that normally erase H3K4me3. Blocking demethylation raised H3K4me3 levels, and, crucially, Pol II and Ser2P signals increased as a result. That causality test ties the epigenetic mark to the transcriptional machinery in a directional way: when H3K4me3 is preserved, the polymerase arrives in greater numbers and proceeds more vigorously into elongation. It also implicates enzymes such as KDM5B, a lysine demethylase targeted by this class of inhibitors, as potential regulators of the ZGA landscape that hypoxia appears to counterbalance.

Not every consequence of hypoxia pointed toward activation. Consistent with the reduced H3K4me3 at repetitive elements, the team found lower LINE1 transcription in hypoxia-cultured embryos, while ERV1 and ERVK retrotransposon transcripts were significantly upregulated under normoxia in keeping with their elevated H3K4me3 marks; LINE2, ERVL, B2 and B4 elements showed no significant differences. This pattern suggests that hypoxia helps the embryo silence potentially destabilizing repeat transcription while sharpening the activation of genuine zygotic genes, a double benefit at a developmental stage when genome integrity and precise timing are both at a premium.

The broader significance of the study lies in the bridge it builds between clinical practice and basic developmental biology. Low-oxygen culture has been a mainstay of assisted reproduction largely on empirical grounds, adopted because embryos simply did better. With this work, the field gains a molecular rationale: hypoxia raises promoter H3K4me3, promotes chromatin accessibility, and orchestrates acute zygotic transcription by fueling both polymerase recruitment and productive elongation. The authors frame their findings as a theoretical foundation for optimizing ART protocols and improving clinical success rates. If the same H3K4me3-dependent mechanism operates in human embryos, it could inform how culture conditions are tuned, how embryo quality is assessed, and potentially how pharmacological agents that modulate histone methylation might be used to rescue embryos that would otherwise arrest. For now, the mouse data provide a vivid picture of an embryo’s first genetic awakening being tuned, quite literally, by the air it breathes, or rather by the carefully reduced oxygen that mimics the environment of the oviduct where early development naturally unfolds.

Subject of Research: Epigenetic regulation of zygotic genome activation under hypoxic embryo culture

Article Title: H3K4me3-dependent transcript elongation drives hypoxia-enhanced zygotic genome activation

Article References: Chen, B., Sun, X., Miao, Y., Sun, S., Deng, M., & Liu, H. (2026). H3K4me3-dependent transcript elongation drives hypoxia-enhanced zygotic genome activation. BMC Biology. https://doi.org/10.1186/s12915-026-02762-w

Image Credits: AI Generated

DOI: 10.1186/s12915-026-02762-w

Keywords: zygotic genome activation, hypoxia, H3K4me3, RNA polymerase II, transcript elongation, embryo culture, assisted reproductive technologies, chromatin, epigenetics, mouse embryo, BMC Biology, fertility

The study began with a deceptively simple question: which genes, when silenced in the fat body, change the growth of organs elsewhere in the animal? Answering it required a screening system that could measure growth in living larvae rather than relying on laborious dissection and imaging. The team engineered a reporter line, dubbed GQ, in which the fat body drives genetic knockdowns while the growth response is read out in peripheral tissues, specifically the imaginal discs, the larval structures that will eventually form adult wings, legs, and eyes. These discs carry a firefly luciferase reporter whose activity scales with tissue growth, while a Renilla luciferase reporter provides an internal reference. By homogenizing individual larvae at a standardized developmental time point, 115 hours after egg deposition, and running dual luciferase assays, the researchers could quantify the growth consequences of each fat-body-specific gene knockdown in a single, rapid measurement.

Using RNA interference lines from the Vienna Drosophila Resource Center, the team systematically knocked down secreted and secretory-pathway genes in the fat body and scored the resulting effects on imaginal disc growth. The primary screen flagged dozens of candidate genes, and a rigorous secondary screen retested each hit with multiple independent RNAi transgenes, including lines from the Bloomington stock center and the National Institute of Genetics in Japan. Only candidates whose effects could be reproduced with independent reagents were considered genuine. Out of the retested genes, 32 were confirmed with high confidence, three showed moderate effects, and 13 failed validation, a sobering reminder of why independent confirmation is essential in genetic screens. Among the confirmed hits, one protein stood out for both the strength of its effect and the elegance of its mechanism: SPARC, short for Secreted Protein Acidic and Rich in Cysteine, also known as BM-40.

SPARC is a matricellular protein, meaning it is secreted into the extracellular environment but does not serve as a structural component of the matrix itself. Instead, matricellular proteins modulate cell-matrix interactions and cell signaling. In mammals, SPARC has been implicated in tissue remodeling, wound repair, fibrosis, and cancer biology, but its role as an endocrine growth regulator had not been established. The new work shows that when SPARC production is reduced in the larval fat body, the entire animal grows less. Adult flies with fat-body SPARC knockdown emerge smaller, with reduced body weight and smaller wings, effects that were quantified by measuring adult dry weight and wing area across multiple independent experiments and temperatures. The consistency of the size reduction across different driver lines and RNAi constructs pointed to a genuine developmental function rather than a technical artifact.

The critical question was how a protein secreted from the fat body could slow the growth of tissues it never touches directly. The answer lies in a small cluster of neurosecretory cells in the larval brain called the insulin-producing cells, or IPCs. These cells are the functional counterparts of human pancreatic beta cells: they release Drosophila insulin-like peptides, particularly Ilp2, into the circulation, and circulating insulin activates the insulin signaling pathway in target tissues, driving cell growth and proliferation. When the researchers examined the IPCs of larvae in which the fat body had been depleted of SPARC, they found that Ilp2 accumulated inside the cells instead of being released. In other words, the peptide was being made but retained, a classic secretory defect. Fat-body SPARC, it appears, is required for the proper endocrine release of insulin from the brain, acting as an incretin-like signal that promotes insulin secretion in response to nutritional conditions.

Several control experiments strengthened this interpretation. A short, one-day depletion of SPARC did not grossly disrupt larval feeding behavior or fat body integrity, arguing against the possibility that the growth defects were secondary to starvation or tissue damage. Larvae with SPARC knockdown still ingested food normally, as shown by feeding assays with dye-labeled yeast paste, and their fat body architecture, visualized with nuclear and membrane stains, remained intact. The team also showed that SPARC is indeed secreted into the hemolymph, the insect circulatory fluid, where it can be detected by western blotting, and that its expression responds to nutritional state, with starvation reducing SPARC mRNA levels in the fat body. These observations fit a model in which the fat body, upon sensing adequate nutrition, secretes SPARC into the circulation, and SPARC in turn stimulates the IPCs to release Ilp2, thereby licensing systemic growth.

Perhaps the most striking result of the study is its evolutionary punchline. When the researchers supplied synthetic human SPARC to fly larvae lacking their own SPARC, the human protein could substitute for the fly version, restoring insulin release and growth. This cross-species rescue demonstrates that the biochemical function of SPARC in this signaling axis has been conserved over hundreds of millions of years of evolution separating insects and vertebrates. It also raises an obvious and tantalizing question for mammalian biology: could SPARC play a comparable role in human insulin regulation? Mammalian incretins, such as GLP-1, are gut-derived hormones that potentiate insulin secretion from pancreatic beta cells, and they form the basis of a major class of diabetes drugs. A fat-derived, SPARC-dependent pathway that promotes insulin release would represent a fundamentally new branch of this regulatory logic, though the authors are careful to frame the human implications as a hypothesis for future work rather than a demonstrated mechanism.

The technical achievement behind the discovery deserves attention in its own right. Traditional genetic screens for growth regulators require laborious measurements of organ size, often by microscopy, which limits throughput and introduces variability. By coupling a tissue-specific knockdown system to a luciferase-based growth readout, the Würzburg team created a pipeline in which a single larva yields a quantitative growth measurement in a plate reader. The dual-reporter design, with firefly luciferase reporting imaginal disc growth and Renilla luciferase normalizing for larval size and handling differences, allowed hundreds of genotypes to be assayed individually. The supplementary data accompanying the paper document the full trajectory of the screen, from the primary results across the tested lines to the validation tables listing every independent transgene and its effect, providing an unusually transparent record of how the conclusions were reached.

Beyond SPARC itself, the study delivers a conceptual message about how growth is coordinated across an animal. The fat body is not merely a passive energy depot; it is an endocrine gland whose secreted products reach into the brain and tune the output of the insulin-producing cells. This architecture mirrors the inter-organ communication circuits of mammals, in which the liver, adipose tissue, gut, and pancreas exchange hormonal signals to match growth and metabolism to nutrient availability. Disruptions in such circuits are central to metabolic disease, and understanding their components in a genetically tractable organism like Drosophila provides a framework for dissecting the corresponding human pathways. The identification of SPARC as an incretin-like, insulin-promoting signal adds a new name to the roster of conserved growth regulators and suggests that the extracellular matrix, long viewed as structural scaffolding, participates directly in endocrine control.

Future experiments will need to determine exactly how SPARC acts on the IPCs, whether it binds a specific receptor on these cells, modulates their secretory machinery, or acts through intermediate signals in the hemolymph. It will also be important to establish whether the SPARC-dependent pathway responds to specific nutrients and how it integrates with other known fat-body-derived signals that influence insulin release and growth. For now, the study stands as a vivid example of modern genetics at work: a systematic in vivo screen, a rigorous validation pipeline, and a mechanistic story that connects a secreted matrix protein in the fat body to insulin granules in the brain and, ultimately, to the size of the adult fly. In doing so, it transforms our picture of how a growing animal counts its calories and converts them into body mass, and it plants a flag for SPARC in a territory where few would have thought to look.

Subject of Research: Fat body-derived SPARC signaling in the regulation of insulin release and systemic larval growth in Drosophila

Article Title: Fat body secreted SPARC promotes Ilp2 release and systemic growth in Drosophila larvae

Article References: Carreno, O., Gallant, M., Grund-Müller, K., Liessem, S., Gramlich, G., Trilla, M. P., Baluapuri, A., Ghoreishi, Y., Gerlach, J., Ache, J. M., Wegener, C., & Gallant, P. (2026). Fat body secreted SPARC promotes Ilp2 release and systemic growth in Drosophila larvae. BMC Biology. https://doi.org/10.1186/s12915-026-02761-x

Image Credits: AI Generated

DOI: 10.1186/s12915-026-02761-x

Keywords: Drosophila, SPARC, insulin signaling, fat body, Ilp2, incretin, larval growth, inter-organ communication, genetic screen, nutrient signaling, insulin-producing cells, BMC Biology

Opsins are the protein workhorses of photoreception across the animal kingdom. Each opsin cradles a light-absorbing molecule derived from vitamin A, and the precise amino acid sequence of the protein tunes the wavelength of light that the complex absorbs most strongly. When a photon is captured, the opsin changes shape and triggers a cascade of chemical reactions inside the photoreceptor cell. Because opsins belong to the vast family of G-protein-coupled receptors, the downstream cascade matters enormously: some visual pigments activate cascades that break down cyclic AMP, a ubiquitous cellular messenger, while others raise it, and the choice of pathway fundamentally shapes how a cell responds to light. Understanding which pathway a given opsin uses is therefore essential to understanding what that opsin actually does for the animal, a point the new study places at the center of opsin evolution research.

The evolutionary backdrop is the teleost whole-genome duplication, often abbreviated TGD, a doubling of the entire genome that occurred in the ancestor of most living ray-finned fish. Genome duplications create spare copies of every gene, and those spare copies are free to mutate, acquire new functions, or fade away. For opsins, the TGD has clearly left its mark: duplicated paralogs of parapinopsin, vertebrate ancient opsin, and the long wavelength-sensitive opsin are known to differ from one another in absorption spectra, in where they are expressed, or in both. Yet, as the authors emphasize, the detailed evolutionary processes and mechanisms by which the TGD drove opsin diversification have remained poorly resolved. Most studies have focused on spectral tuning, the easiest property to measure, while the signaling behavior of duplicated opsins has been largely unexplored territory.

The team’s starting point was a survey of opsin genes across characins, the order of fish that includes piranhas, tetras, and their relatives. Several characins, they found, have retained two TGD-derived paralogs of parietopsin, which the researchers designated PT1 and PT2. This is unusual. Most teleosts, including the laboratory workhorse zebrafish, possess only PT1, while the Mexican tetra, Astyanax mexicanus, and various catfishes carry only PT2. The patchy distribution suggests that different fish lineages have kept different copies of this duplicated gene pair over tens of millions of years, a pattern that raises immediate questions about whether the two paralogs do different jobs and why some lineages abandoned one copy while others kept the other.

To answer those questions, the researchers characterized the two piranha proteins on three fronts: the wavelengths of light they absorb, the intracellular signaling pathways they engage, and the cells in which their genes are switched on. Measuring absorption spectra required expressing the proteins, reconstituting them with their light-sensitive chromophore, and spectroscopically probing the purified pigments. The results showed that the two paralogs are spectrally close but not identical. Red piranha PT1 absorbs maximally at 517 nanometers, in the green part of the spectrum, while red piranha PT2 peaks at 528 nanometers, a modest red-shift. Mexican tetra PT2 peaks at 517 nanometers, matching piranha PT1, and the PT2 of the Japanese catfish, Silurus asotus, absorbs at approximately 535 nanometers, the most red-shifted of the group.

The signaling experiments delivered the study’s most striking result. Using a heterologous cell-based assay, in which the fish opsins are expressed in cultured cells equipped with sensitive reporters, the team found that red piranha PT1 and PT2 couple to opposite signaling directions. When illuminated, PT1 increased the level of cyclic AMP in the cells, whereas PT2 decreased it. Neither parainopsin paralog, notably, produced a clear calcium response under the conditions tested. In practical terms, two proteins that descended from a single ancestral gene, absorb nearly the same green light, and sit in the same cells, push cellular chemistry in opposite directions when the lights come on. This kind of functional divergence, invisible to any study that measures only absorption spectra, is precisely what the authors argue has been missing from the picture of how genome duplication fueled opsin diversification.

The expression analysis added a further layer of surprise. Using fluorescence in situ hybridization, a technique that reveals exactly which cells contain specific messenger RNAs, the researchers showed that piranha PT1 and PT2 are co-expressed in the same pineal cells. Even more intriguingly, both are also co-expressed with parapinopsin 1, another pineal opsin whose duplicated teleost paralogs are known to have diversified. The pineal gland of the piranha therefore appears to be a densely multiplexed light-sensing tissue, packing at least three opsins, including two with opposing signaling polarities, into the same photoreceptive cells. How the cell integrates light signals that simultaneously raise and lower cyclic AMP is now an open and tantalizing question, one that could reshape assumptions about how simple, non-visual light detection works in fish.

The broader evolutionary implications reach well beyond piranhas. The retention patterns the team documented, with zebrafish keeping PT1, Mexican tetras and catfishes keeping PT2, and piranhas keeping both, illustrate that the fate of duplicated genes has played out differently across teleost lineages. Where both copies survive, functional divergence, in signaling if not in spectra, may be what allows them to coexist without redundant competition. Where only one copy survives, the lost paralog’s function may have been absorbed or rendered unnecessary. The study thus provides a concrete case study in a general principle: after genome duplication, the diversification of gene function can proceed through changes in signaling biochemistry, not merely through shifts in the physical properties of the protein’s light-sensitive pocket.

There is also a methodological lesson embedded in the findings. Had the researchers stopped at spectral measurements, PT1 and PT2 would have looked like near-identical twins, differing by a mere 11 nanometers in peak absorption. Only by assaying intracellular signaling did the deep functional split between the two paralogs come into view. The authors conclude that characterizing signaling properties is essential for understanding how the teleost genome duplication contributed to opsin diversification, and the implication for the field is clear: future surveys of duplicated opsins, in fish and beyond, will need to measure what these proteins do inside cells, not just what color of light they catch. As genome sequences accumulate from ever more fish species, studies of this kind promise to reveal how an ancient doubling of DNA, hundreds of millions of years ago, still shapes the way modern fish sense their world, from the green-lit shallows where tetras school to the murky rivers where piranhas swim with a light compass hidden in their brains.

Subject of Research: Functional diversification of duplicated parietopsin opsins after the teleost whole-genome duplication

Article Title: Two piranha parietopsins illuminate opsin diversification in teleosts

Article References: Sato, K., Yamashita, T., Sakai, K., Ohuchi, H., Kusakabe, T. G., & Gyoja, F. (2026). Two piranha parietopsins illuminate opsin diversification in teleosts. BMC Biology. https://doi.org/10.1186/s12915-026-02759-5

Image Credits: AI Generated

DOI: 10.1186/s12915-026-02759-5

Keywords: parietopsin, opsin, teleost whole-genome duplication, red piranha, pineal gland, photoreception, cyclic AMP, G-protein-coupled receptor, Mexican tetra, catfish, fluorescence in situ hybridization, BMC Biology

The factor in question is DAF-16, the nematode worm Caenorhabditis elegans equivalent of the mammalian FOXO family of transcription factors. DAF-16 sits at the bottom of the insulin/IGF signalling pathway, a nutrient-sensing cascade whose reduction reliably extends lifespan across the animal kingdom. When insulin-like signals are low, DAF-16 accumulates in the nucleus and switches on batteries of genes involved in stress resistance, detoxification and metabolic remodelling. Because DNA repair is an energetically expensive undertaking, biologists have long suspected that it must be coordinated with the metabolic state of the cell, and the insulin pathway was an obvious candidate coordinator. What remained unclear was whether DAF-16 directly participates in maintaining genomic integrity or merely influences it indirectly through general stress physiology.

To answer that question, the team subjected worms with altered insulin signalling to genotoxic stress, including ionising radiation, and then measured how well the animals repaired the resulting lesions. The results were striking. Under conditions of reduced insulin/IGF signalling, when DAF-16 is active, the expression of DNA damage response repair genes was maintained at a higher level, and damaged DNA was repaired more promptly. Using chromatin immunoprecipitation-style approaches to examine promoter occupancy, the researchers found that activated DAF-16 binds directly to the regulatory regions of DDR genes, demonstrating that the transcription factor is not a passive bystander but an active, sequence-specific regulator of the repair programme.

This direct promoter binding is the mechanistic heart of the study. It means that when insulin signalling drops, DAF-16 enters the nucleus and physically parks itself on the genes encoding repair proteins, holding them in a state of readiness. Should a double-strand break or other lesion occur, the repair machinery is already being produced at elevated levels, allowing the cell to respond without the delay that would otherwise be required to ramp up gene expression from scratch. In effect, low insulin signalling pre-arms the genome’s emergency response, a configuration that makes evolutionary sense for an organism facing starvation or other stresses that also increase the risk of DNA damage.

One of the study’s most important findings concerns where in the animal DAF-16 operates. C. elegans contains two broadly distinct cellular compartments: the mitotic and meiotic germ cells that produce sperm and eggs, and the post-mitotic somatic cells that make up the body. The researchers determined that DAF-16 functions in both. In the soma, its activity supports the integrity of cells that can no longer divide and must simply endure damage for the remainder of the animal’s life. In the germline, its role is arguably even more critical, because the genome passed to the next generation must be protected from mutations that would become permanent heritable changes. The finding that a single nutrient-responsive transcription factor safeguards both compartments suggests that the insulin pathway coordinates genome maintenance across the entire organism rather than in a tissue-specific fashion.

The study then drilled down into the molecular fine print of DAF-16 itself. Like its mammalian FOXO cousins, DAF-16 exists as several protein isoforms generated by alternative splicing, each with slightly different sequence features and, presumably, different regulatory targets. When the team tested these isoforms individually, they discovered a clear division of labour: the DAF-16(d/f) isoform, but not the DAF-16(a) isoform, is essential for maintaining germline genome integrity. This isoform specificity is more than a technical curiosity. It implies that the different FOXO variants carved out by evolution are not interchangeable generalists but specialised tools, and it offers a potential explanation for why mammals maintain multiple FOXO genes with overlapping yet distinct functions in stress responses, metabolism and tumour suppression.

How, mechanically, does DAF-16 enhance the DNA damage response? The researchers found that the bulk of the enhancement flows through the canonical DDR components themselves, the conserved sensor and effector proteins such as the ATM-like kinases and the downstream repair pathways including homologous recombination and non-homologous end joining that mend double-strand breaks. By keeping the expression of these core components elevated, DAF-16 strengthens the primary repair machinery. Interestingly, however, the analysis revealed a secondary contribution from apoptosis, the programmed suicide of severely damaged cells. In the germline, cells whose genomes are too badly damaged to repair are normally eliminated as a failsafe, and DAF-16 activation appears to support this clearance pathway as well, albeit to a lesser extent than direct repair. Genome maintenance, in other words, is achieved through a two-pronged strategy: fix what can be fixed, and remove what cannot.

The evolutionary implications of the work are considerable. FOXO transcription factors are among the most conserved regulators of longevity known, operating in organisms from fruit flies to humans, and mammalian FOXO proteins have previously been implicated in DNA repair and tumour suppression. By establishing a direct, mechanistic role for DAF-16 in the DDR of C. elegans, the New Delhi team demonstrates that this function is conserved across the evolutionary divide separating worms and mammals. The study thus closes a conceptual loop in the biology of ageing: the same nutrient-sensing pathway that determines how long an animal lives also determines how faithfully its cells preserve the genetic instructions that make life possible in the first place. Longevity and genome stability, it turns out, are two faces of the same coin.

There are also practical horizons. Because reduced insulin/IGF signalling is a proven longevity intervention, and because DAF-16/FOXO sits at its downstream end, the new findings suggest that some of the health benefits of dampening insulin signalling may derive not from metabolic changes alone but from a strengthened capacity to repair DNA. In humans, where genomic instability underlies cancers, premature ageing syndromes and age-related tissue decline, understanding how FOXO activity could be tuned to bolster the DDR without unwanted side effects becomes an attractive pharmacological goal. The worm, with its transparent body, rapid life cycle and precisely mapped cell lineages, remains the ideal proving ground for such ideas.

For now, the study stands as a reminder that the molecules biologists thought they had categorised often harbour unexpected day jobs. DAF-16 earned its fame as a lifespan determinant, a switch that, when flipped by scarcity, extends life in the nematode. The new work shows that the same switch also keeps the genome intact under assault from radiation and other genotoxic insults, in both the cells of the body and the cells destined to become the next generation. In linking the insulin pathway, transcriptional regulation and the DNA damage response into a single coherent circuit, Devendran, Rautela, Sarkar, Mukhopadhyay and their colleagues have provided mechanistic insight into how an animal balances the energy demands of repair with the imperative of survival, and how evolution has wired the perception of nutrients directly into the defence of the genetic code itself.

Subject of Research: Role of DAF-16/FOXO in maintaining genome integrity through the DNA damage response in C. elegans

Article Title: DAF-16/FOXO maintains genome integrity following genotoxic stress

Article References: Devendran, O., Rautela, U., Sarkar, G. C., Ranjisha, K., Mittal, R., Bala, R., Goyala, A., & Mukhopadhyay, A. (2026). DAF-16/FOXO maintains genome integrity following genotoxic stress. BMC Biology. https://doi.org/10.1186/s12915-026-02755-9

Image Credits: AI Generated

DOI: 10.1186/s12915-026-02755-9

Keywords: DAF-16, FOXO, DNA damage response, genome integrity, C. elegans, insulin/IGF signalling, DNA repair, germline, ageing, genotoxic stress, BMC Biology, maintains

The challenge that motivated the work is rooted in the physics of nanopore sequencing. As an RNA or DNA molecule threads through a protein pore, the sequencer records characteristic disruptions in ionic current, and basecalling algorithms translate those disruptions into sequence. Homopolymer runs, long stretches of a single base such as the adenines in a poly(A) tail, produce nearly identical current signals base after base, making it hard to count exactly how many adenines are present. On top of that, the 3′ ends of transcripts are architecturally complex: the boundary between the end of the transcript proper and the start of the tail can be fuzzy, alternative polyadenylation sites can generate multiple transcript isoforms from a single gene, and repetitive elements, including remnants of endogenous retroviruses, can complicate the identification of where a transcript truly terminates.

PolyAnalysis tackles these problems at the signal level rather than working from basecalled sequence alone. The framework combines a convolutional neural network with a bidirectional long short-term memory network, a pairing commonly abbreviated as CNN–BiLSTM, to classify regions of the raw signal as poly(A)-proximal or otherwise. It then applies a multi-task connectionist temporal classification decoding scheme, adapted from speech recognition, to infer the boundaries of the poly(A)-proximal region and the tail length itself. Crucially, the authors built adenine-aware training and decoding into the pipeline: the loss function used during training weights adenine-related errors differently, and the decoding step is biased toward A-rich interpretations, reflecting the biological expectation that the region of interest is dominated by adenines.

Benchmarking was carried out against three established tools: Nanopolish, tailfindr, and Dorado. The evaluation used controlled datasets generated with both RNA002 and RNA004 nanopore chemistries, allowing the team to assess performance across sequencing generations. According to the study, PolyAnalysis achieved tail-length accuracy that was competitive with the existing methods while delivering high callability, meaning it produced usable estimates for a larger fraction of reads. The authors stress that tail-length estimation is the most extensively validated output of the framework, and they are careful not to overstate the maturity of the other analyses the tool offers.

To understand which components of the model actually mattered, the researchers performed component-wise ablation experiments, systematically removing or altering parts of the pipeline and measuring the effect on performance. They also ran bias-control analyses. The results indicated that the region classification module, the multi-task optimization objective, the adenine-weighted loss, and the A-rich decoding strategy each contributed to the overall performance, suggesting that the design choices were not arbitrary but jointly responsible for the accuracy gains. This kind of ablation work is increasingly expected in machine learning applied to genomics, where it is easy to attribute improvements to a single flashy component when in fact the benefit comes from an interplay of design decisions.

Beyond tail length, PolyAnalysis links its per-read estimates to analyses of polyadenylation sites, alternative polyadenylation, and repetitive-element-associated 3′ ends. When applied to human cell-line datasets and vertebrate transcriptome datasets, the framework identified variation in tail-length distributions at the dataset level and heterogeneity at the gene level. It also found only weak associations between tail length and steady-state transcript abundance, a finding that adds nuance to the widely held expectation that longer tails should reliably predict more abundant or more translated transcripts. The relationship between tail length and expression, the data suggest, is more context-dependent than simple models imply.

One of the more distinctive features of the framework is its confidence-based filtering of polyadenylation sites. Rather than presenting all detected sites as equally reliable, PolyAnalysis separates them into database-matched high-confidence sites, novel candidates flagged with high confidence, and low-confidence calls. This tiered output acknowledges a persistent problem in 3′ end profiling: novel polyadenylation sites predicted from sequencing data can reflect genuine biology or merely artifacts of alignment, basecalling, or annotation gaps. By making confidence explicit, the tool gives downstream users a principled way to decide which calls to trust for follow-up experiments.

The treatment of endogenous retroviruses illustrates the same caution. Retroviral remnants scattered through the genome can supply polyadenylation signals to nearby genes, and distinguishing true locus-level evidence of such events from family-level patterns, where many similar retroviral sequences produce ambiguous signals, is genuinely difficult. PolyAnalysis applies ambiguity-aware analysis to separate these two levels of evidence, and the authors are explicit that the sequence-composition, polyadenylation-site, alternative-polyadenylation, and endogenous-retrovirus-related results all remain dependent on model assumptions, sequencing chemistry, and annotation quality, and require further orthogonal validation before being treated as established biology.

The significance of the work lies partly in its scope. Alternative polyadenylation is a major layer of gene regulation: by choosing a proximal or distal polyadenylation site, a cell can change the untranslated region of a transcript and thereby alter its stability, localization, and translation efficiency, with documented roles in development, immunity, and cancer. Tools that can profile these choices per read, on long-read platforms that capture full transcript molecules, offer a view that short-read sequencing cannot easily provide. By coupling tail-length estimation with polyadenylation-site analysis in a single signal-level framework, PolyAnalysis aims to make that view more accessible to laboratories that already run nanopore sequencers.

The study, a software contribution from researchers at Hunan University, Hunan University of Finance and Economics, and the University of Electronic Science and Technology of China, was supported by the National Natural Science Foundation of China and involved secondary analysis of publicly available datasets. The framework is published open access under a Creative Commons Attribution license, and the authors have released supplementary figures, tables, and numerical source data underlying the main results. For a field where poly(A) tail measurement has often been a bespoke, error-prone exercise, a benchmarked, confidence-aware pipeline that works across both RNA002 and RNA004 chemistries represents a practical step forward, even as the authors themselves caution that the most exploratory parts of their analysis, particularly the retrovirus-associated findings, should be treated as hypotheses awaiting independent confirmation rather than settled results.

Subject of Research: Deep learning-based estimation of poly(A) tail length and 3′-end regulation profiling from nanopore sequencing data

Article Title: PolyAnalysis: a deep learning–based framework for nanopore-based poly(A) tail estimation and 3′-end regulation profiling

Article References: Tian, Q., Song, B., Zou, Q., & Wang, Y. (2026). PolyAnalysis: a deep learning–based framework for nanopore-based poly(A) tail estimation and 3′-end regulation profiling. BMC Biology. https://doi.org/10.1186/s12915-026-02749-7

Image Credits: AI Generated

DOI: 10.1186/s12915-026-02749-7

Keywords: poly(A) tail, nanopore sequencing, deep learning, alternative polyadenylation, polyadenylation site, long-read transcriptomics, connectionist temporal classification, endogenous retrovirus, RNA sequencing, 3′ end regulation, Oxford Nanopore Technologies, BMC Biology

The research tackles a long-standing question in sensorimotor science. When we reach for an object, our grip force rises in anticipation of its weight, a phenomenon known as anticipatory grip force control. If the prediction is right, the lift feels smooth and effortless. If it is wrong, the object either slips from our fingers or jerks upward with comical force. Decades of work have shown that these predictions are built from two ingredients: visual cues, most obviously the apparent size or volume of the object, and the memory of recent lifting experience. A large-looking bottle is expected to be heavy; a bottle that felt heavy last time is expected to feel heavy again.

That second ingredient turns out to be surprisingly dominant. In the Durham experiments, when participants lifted objects with no informative visual cues at all, their grip force behaviour was strongly biased by whatever they had lifted on the previous trial. This serial dependence, the tendency of the most recent experience to colour the next prediction, has been documented in perception before, but the new results show it exerting a powerful pull on motor planning itself. Left to its own devices, the lifting system essentially assumes the world has not changed since the last interaction.

The team measured this bias using peak grip force rate, or PGFR, the speed at which grip force climbs during the initial phase of a lift. PGFR is a well-established window into the brain’s internal heaviness predictions because it reflects what the motor system expected before tactile information arrived. Participants performed a precision-grip lifting task in which objects came in three heaviness levels, and the researchers tracked how PGFR shifted across four experimental conditions: a no-cue baseline, a familiar cue, and two kinds of novel cues.

The familiar cue was visual volume, the everyday signal that bigger means heavier. The novel cues were deliberately arbitrary: patterns of line orientations printed on the surfaces of the objects, with no natural relationship to weight. Crucially, the researchers also split the novel cues by presentation format. In the intrinsic condition, the line patterns appeared physically on the objects themselves, much as a label might. In the extrinsic condition, participants saw diagrammatic depictions of the same objects and patterns on a screen, meaning the weight information was available only through an interpretive step rather than being directly attached to the thing being lifted.

Before running the study, the authors had reasoned that the familiar volume cue might carry more predictive weight than an arbitrary pattern, simply because a lifetime of experience has calibrated the size-weight relationship. They also suspected that cues printed on the object might outperform cues shown on a screen, since intrinsic presentation requires no mapping between a display and the physical world. Neither prediction survived contact with the data. The familiar volume cue did not exert a stronger influence than the novel cues, and the intrinsic presentation offered no measurable advantage over the extrinsic one.

What did matter was simply having a cue at all. All three visual cue conditions significantly reduced the serial dependence bias compared with the no-cue baseline. In other words, any reliable visual signal about weight, whether natural or arbitrary, on-object or on-screen, was enough to loosen the grip of recent experience and let the motor system plan each lift on its own terms. The computational modelling accompanying the behavioural data, with individual cue-weighting parameters fitted for each participant, supported the same conclusion: novel cues were integrated into the heaviness prediction with weights comparable to those of the familiar cue.

The speed of this learning is the most striking aspect of the findings. Participants did not need weeks of training to make an arbitrary line orientation meaningful. The sensorimotor system, often portrayed as conservative and heavily reliant on long-term calibration, absorbed the new cue rapidly and deployed it in service of grip force planning without any apparent performance penalty. This suggests that the machinery of motor prediction is less wedded to specific cue types than theories emphasising learned cue familiarity might imply, and more open to whatever statistical regularities the environment currently offers.

The equivalence of intrinsic and extrinsic presentation carries equally interesting implications. Much of the emerging field of sensory augmentation assumes that information delivered through artificial channels, such as a display or a wearable device, will be harder to incorporate than information arriving through the body’s native senses. These results suggest that, at least for weight prediction in a controlled lifting task, the brain treats a diagrammatic on-screen cue as a perfectly serviceable predictor. The interpretive distance between a screen and an object did not dilute the cue’s influence on motor planning.

The practical implications extend beyond the laboratory. In industrial settings, medical environments, logistics and teleoperation, workers routinely handle objects whose weight cannot be judged by appearance, from sealed containers to virtual or robotic proxies. The findings suggest that equipping such environments with arbitrary visual markers, even simple line patterns shown on a monitor, could rapidly improve the safety and efficiency of manual handling by steadying grip force against the misleading pull of recent experience. For designers of augmented reality interfaces, the message is encouraging: the human motor system appears ready to trust whatever weight information you show it, almost immediately, and without demanding that the information be painted onto the object itself. As the authors note, the work highlights the flexibility of sensorimotor control and may inform manual interactions in environments with limited or unconventional weight predictors, a description that fits an increasing share of the technological world we now lift, carry and manipulate every day.

Subject of Research: How novel visual cues are learned to update internal predictions of object weight during lifting

Article Title: Learning a novel visual cue to update internal predictions of object weight

Article References: Kristiansen, O., Scheller, M., & Nardini, M. (2026). Learning a novel visual cue to update internal predictions of object weight. BMC Biology. https://doi.org/10.1186/s12915-026-02741-1

Image Credits: AI Generated

DOI: 10.1186/s12915-026-02741-1

Keywords: grip force, motor planning, visual cues, object weight, serial dependence, sensorimotor control, anticipatory control, precision grip, sensory augmentation, psychophysics, BMC Biology, Durham University

The traditional route to identifying a sex pheromone has always been laborious. Researchers must typically maintain live colonies of the target insect, collect and extract the chemicals emitted by females, and then sift through a complex mixture of dozens or even hundreds of volatile compounds to determine which ones actually attract males. The timing of pheromone production matters enormously, since many species release their signals only during narrow windows of the day or night, and missing that window can mean missing the signal entirely. Once candidate compounds are isolated, each must be tested for behavioural activity, often through wind-tunnel experiments or field trials, before the true pheromone can be confirmed. For rare species, invasive pests that have just appeared in a new region, or insects that are difficult to rear in captivity, this process can stall for years, leaving pest managers without the species-specific tools that pheromone-based control depends on.

The INRAE team, working within the EXPLOR’AE Programme funded through the project known as Invoria, chose to invert this logic entirely. Rather than starting with the emitter of the chemical signal, they started with the receiver: the male moth, and more specifically, the olfactory receptors housed in his antennae that are tuned to detect the female’s scent. Their study species was the lily moth, Spodoptera picta, a strikingly coloured insect whose sexual communication had never been described. The lily moth is what biologists call a non-model organism: it is not a standard laboratory species with a rich history of prior research, and this was precisely the point. If the method could work on a poorly studied insect with no established toolkit, the researchers reasoned, it could likely be extended to many other species that currently resist conventional analysis.

The first step of the reverse approach relied on genomics. By analysing the genes of the lily moth and comparing them with those of related species, the researchers narrowed down a catalogue of candidate olfactory receptors to two promising candidates. This comparative step matters because receptor genes evolve alongside the chemicals they detect; receptors in closely related species that respond to similar pheromones often share detectable similarities in their sequences. From this genetic starting material, the team turned to artificial intelligence. Machine-learning tools were used to predict the three-dimensional structures of the two candidate receptors, generating models of the protein shapes that sit in the membranes of sensory neurons and cradle odorant molecules as they arrive from the air.

With structural models in hand, the researchers applied molecular docking, a computational technique widely used in drug discovery, to predict which volatile molecules would fit and bind within the receptors’ binding pockets. Docking simulations evaluate how two molecules can interact spatially and energetically, scoring the likelihood that a given compound will make stable contact with a target protein. By screening a library of volatile compounds against the modelled receptors, the computational pipeline identified a specific molecule predicted to interact strongly with both candidate receptors: (Z,E)-9,11-tetradecadienyl acetate. In effect, the algorithm had proposed an answer to a question the insects had never been asked in the laboratory: what chemical does the female of this species use to signal her availability?

Prediction alone, however, is never sufficient in biology, and the team followed the computational phase with a rigorous sequence of experimental validation. First, the selected olfactory receptors were tested directly against the predicted volatile molecules using electrophysiological methods, which measure the electrical responses of sensory cells or expressed receptor proteins when exposed to chemical stimuli. The receptors responded, confirming computationally predicted interactions with real physiological activity. Next, the researchers combined physicochemical analysis with electrophysiology to verify two crucial facts: that female lily moths actually secrete the predicted compound as their sex pheromone, and that male moths can detect the volatile molecule in the air. These analytical steps confirmed that the AI-guided prediction matched what the insects themselves were doing.

The final and most demanding test was behavioural. A molecule may be detected by an antenna, but detection does not guarantee attraction; only a behavioural response demonstrates that the compound functions as a genuine pheromone in the life of the animal. In behavioural assays, the identified compound attracted male lily moths and elicited sexual behaviour, completing the chain of evidence from gene to receptor to molecule to mating behaviour. Taken together, the results show that an unknown pheromone of a non-model species could be identified through a pipeline that begins with sequencing, passes through AI-predicted receptor structures and molecular docking, and ends with classical electrophysiology and behavioural experiments. Each stage filtered and focused the search, dramatically reducing the number of candidate chemicals that needed laboratory testing.

The significance of this proof of concept extends well beyond a single moth species. Current, emerging and invasive crop pests are precisely the organisms for which pheromone identification is most urgently needed and most often missing, because invasive populations can spread faster than conventional chemical ecology can characterise them. Once a species’ sex pheromone is known, two well-established biocontrol strategies become available. Mating disruption involves flooding an area, such as a crop field or orchard, with synthetic pheromone so that males become unable to locate females, crashing reproduction without any toxic chemical. Alternatively, pheromone-baited traps can be used to estimate population density, monitor invasions, or suppress populations through mass trapping. Both approaches are highly species-specific, sparing beneficial insects such as pollinators and natural enemies of pests, and both are compatible with the increasingly strict regulations governing pesticide use in gardens, parks and botanical collections.

The lily moth itself illustrates why such tools matter. The species is not found in mainland France and is therefore not considered a pest of concern there, which made it an ethically convenient and scientifically demanding test case. Yet elsewhere in the world, Spodoptera picta is a significant pest, particularly in private gardens, public parks and botanical gardens, settings where the use of conventional pest-control products is often tightly restricted and where ornamental plants suffer real damage. A validated pheromone-based method could give managers in those regions a targeted, low-toxicity option, and the study’s authors note that this work opens up the possibility of using pheromone-based methods to control the moth. In this sense, the research delivers both a general technique and a concrete practical outcome for a real agricultural problem.

There is also a deeper scientific payoff. Pheromones function as chemical signatures of species, and the molecules a species uses to communicate sexually contribute to reproductive isolation, helping to keep related species distinct. As a result, identifying the compounds that make up the pheromones of moths and other insects offers new insights into the evolutionary history of these lineages, revealing how chemical communication has diverged and shaped speciation. By making pheromone identification faster and less dependent on scarce live insects, the reverse chemical ecology approach demonstrated here could populate the field with many more of these chemical signatures, allowing biologists to reconstruct communication systems across entire groups of species. What began as a pest-management problem thus ends as a window onto evolution, powered by artificial intelligence, and a demonstration that sometimes the fastest way to understand a signal is to study the ear rather than the voice.

Subject of Research: AI-guided prediction of insect olfactory receptors to identify moth sex pheromones for crop protection

Article Title: Crop protection: a new method for understanding insect sexual communication

Article References: Crop protection: a new method for understanding insect sexual communication. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: pheromones, chemical ecology, olfactory receptors, Spodoptera picta, biocontrol, mating disruption, molecular docking, artificial intelligence, INRAE, BMC Biology, invasive pests, lily moth

The research, led by Lu-Yan Chan, Ming-Kin Wong, and Yong-Hong Yan as co-first authors in the laboratory of Zhongying Zhao at Hong Kong Baptist University, with collaborators at the National Institute of Biological Sciences in Beijing and the University of Science and Technology of China, focuses on CYL-1, the worm counterpart of cyclin L1. Cyclins are best known as the rhythmic partners of cyclin-dependent kinases, the enzymes that drive cells through the phases of the cell cycle. Yet a growing body of work has revealed that many cyclins moonlight in other processes, and cyclin L had previously been implicated in pre-mRNA splicing through its interaction with CDK-11 in cultured cell lines. What remained murky was whether this splicing connection mattered in a living, developing animal—and what else the protein might be doing there.

To find out, the team first established where and when CYL-1 operates. Fluorescently tagged versions of the protein revealed that CYL-1 is expressed ubiquitously, residing in cell nuclei throughout the entire course of worm development. That broad, persistent nuclear presence hinted that the protein is not a niche player confined to one tissue or stage, but a general component of the gene-expression machinery whose loss should ripple across the organism. The next step was to identify who CYL-1 actually works with inside those nuclei.

Using co-immunoprecipitation followed by mass spectrometry—a technique in which a bait protein is pulled down from worm extracts along with everything physically bound to it, and the captured partners are then identified by their peptide fingerprints—the researchers mapped CYL-1’s interaction network in vivo. The results confirmed that CYL-1 forms complexes with two worm CDK-11 isoforms, CDK-11.1 and CDK-11.2, and also identified a highly conserved protein called EELO-1, named for its association with early transcriptional elongation, as a core interactor. Together with the splicing-associated factor SAP30BP highlighted in the study’s title, these proteins define a complex that sits at the junction of transcription and RNA processing.

Genetic analysis then revealed how essential this machinery is. When the researchers interfered with cyl-1, cdk-11.1, cdk-11.2, or eelo-1 using RNA interference, embryos failed to develop normally, and the two CDK-11 paralogs were shown to act redundantly: knocking down either alone was survivable to a degree, but compromising both sharply reduced embryonic viability. This redundancy is a classic signature of duplicated genes that share a critical function, and it means the worm tolerates losing one copy of the kinase only because the other can carry the load. The four proteins, in other words, are not optional accessories but load-bearing pillars of mRNA biogenesis during embryogenesis.

The mechanistic heart of the study lies in what those pillars actually do to RNA. Immunostaining assays, which use antibodies to visualize the location of specific molecular marks on proteins, showed that loss of CYL-1 disrupts events at the very start of the transcription cycle, affecting transcriptional initiation and the elongation of RNA polymerase along the gene body. RNA sequencing of embryos depleted of each complex member added a genome-wide view: beyond changes in overall transcript levels, the researchers documented widespread defects in pre-mRNA splicing, with alternative splicing patterns shifting substantially and differently depending on which of the four genes—cyl-1, cdk-11.1, cdk-11.2, or eelo-1—had been silenced. That last detail matters. If the four proteins were simply interchangeable parts of one machine, depleting any of them would produce the same splicing fingerprint. Instead, each leaves a distinct signature, suggesting partially specialized roles within a shared complex.

Perhaps the most striking finding came from asking a developmental question rather than a biochemical one. Using established cell fate markers—reporter constructs that fluoresce only when a cell has committed to a particular identity—the team demonstrated that CDK-11.1, CDK-11.2, and EELO-1 are involved in regulating cell fate specification during development. In an embryo, every cell carries the same genome; what distinguishes a muscle cell from a neuron is which subset of genes is transcribed and how those transcripts are processed. A complex that influences both transcriptional output and splicing is therefore ideally positioned to shape that decision, and the new data indicate that it does. The result reframes splicing factors not merely as editors of genetic text but as participants in the regulatory logic that assigns identities to embryonic cells.

Importantly, the study also uncovers an asymmetry within the complex. While CYL-1 is required for transcriptional initiation, elongation, and splicing, its partners CDK-11.1, CDK-11.2, and EELO-1 carry the additional responsibility of governing cell fate determination—a role that CYL-1 itself did not show in these assays. This differential division of labor between a cyclin and its interactors adds a nuanced twist to cyclin biology. It suggests that the familiar cyclin-CDK pairing can be modular: the kinase and its associated factors may perform functions beyond, and independent of, the cyclin that helps recruit or activate them. For an organism as experimentally tractable as C. elegans, whose transparent embryos allow researchers to watch every cell division in real time, such a system offers a powerful platform for dissecting how those roles are partitioned at the molecular level.

The evolutionary implications extend well beyond worms. CDK-11 and cyclin L are conserved across metazoans, including mammals, where CDK11 has been implicated in cell cycle control, apoptosis, and RNA processing, and where splicing deregulation is increasingly recognized as a driver of developmental disorders and cancer. EELO-1’s conservation means the worm findings likely illuminate a broadly shared architecture of gene expression. If a CDK-11-containing complex couples transcriptional elongation and splicing to cell fate decisions in nematodes, the same coupling may operate in vertebrate embryos, stem cells, and disease states where differentiation goes awry. The study does not test these possibilities directly, but it establishes the in vivo framework that such future work in other organisms can build upon.

What makes the work resonate beyond its immediate field is the picture it paints of gene expression as a single, physically continuous process rather than a relay of disconnected stages. The RNA polymerase that reads a gene, the factors that splice its transcript, and the regulatory network that decides a cell’s destiny are, in this emerging view, held together in one macromolecular assembly. A defect anywhere in that assembly—an underactive kinase, a missing cyclin, an absent elongation factor—can propagate outward from a biochemical glitch to a developmental outcome: an embryo that fails to survive, or a cell that adopts the wrong identity. By grounding that logic in the concrete genetics of a living animal, the Hong Kong-led team has turned a splicing complex into a lens on one of biology’s deepest questions—how a genome becomes an organism—and provided a molecular handle that researchers studying development, RNA biology, and disease will now be eager to pull.

Subject of Research: The role of a CYL-1/CDK-11/EELO-1 complex in pre-mRNA splicing and cell fate specification during C. elegans development

Article Title: A CDK-11/SAP30BP/CYL-1 complex links pre-mRNA splicing to developmental cell fate decisions

Article References: Chan, L.-Y., Wong, M.-K., Yan, Y.-H., Ho, V. W. S., Ma, Y., Xie, D., Ye, P., Zeng, J., Dong, M.-Q., Guang, S., & Zhao, Z. (2026). A CDK-11/SAP30BP/CYL-1 complex links pre-mRNA splicing to developmental cell fate decisions. BMC Biology. https://doi.org/10.1186/s12915-026-02734-0

Image Credits: AI Generated

DOI: 10.1186/s12915-026-02734-0

Keywords: CYL-1, CDK-11, EELO-1, pre-mRNA splicing, cell fate determination, C. elegans, embryogenesis, cyclin-dependent kinase, transcriptional elongation, developmental genetics, mRNA biogenesis, BMC Biology

The team, led by Diogo Coutinho-Lima and Raquel Godinho of the University of Porto’s CIBIO research centre, together with colleagues in Spain, set out to solve a puzzle that has long intrigued canine geneticists. Iberia is home to an impressive array of livestock working dogs, from massive livestock guarding breeds such as the Spanish Mastiff and the Estrela Mountain dog to nimble herding specialists like the Basque, Castilian, Leonese and Galician sheepdogs. These dogs were bred for fundamentally different jobs: guarding dogs protect flocks from predators, while herding dogs control and move them. On the surface, such strong selection for distinct tasks should have driven the two groups apart genetically. Yet when the researchers examined the dogs’ genomes, that is not what they found.

To probe the question, the team assembled an unusually rich dataset. They combined Y-linked and autosomal microsatellite markers, which are short tandem repeats scattered across the genome that are useful for tracking recent ancestry, with genome-wide single nucleotide polymorphism data, or SNPs, which capture variation across hundreds of thousands of positions in the DNA. The 445 sampled Iberian livestock dogs were compared with village dogs, wolves and a global panel of modern dog breeds, allowing the researchers to place the Iberian animals in a worldwide context. Analytical tools included principal component analysis, PHATE and UMAP dimensionality reduction, ADMIXTURE clustering, analysis of molecular variance, fixation index comparisons, haplotype sharing tests, and migration models that infer historical gene flow between populations.

The first major result was reassuring for the health of these breeds: Iberian livestock dogs retain high genetic diversity and generally low levels of inbreeding. Measures such as expected heterozygosity, allelic richness and haplotype diversity were comparatively high, while inbreeding coefficients and signals of homozygosity by descent were modest. This stands in contrast to many modern pedigree breeds, which have often experienced intense bottlenecks and closed studbooks that concentrate harmful recessive variants. The researchers also inferred recent effective population size trajectories, which suggested that these working populations have historically been large enough to avoid the erosion of diversity that plagues many registered breeds.

The second and more surprising finding concerned population structure. Despite the clear behavioural and morphological gulf between guarding and herding dogs, the genome-wide data showed little evidence of differentiation between the two working types. Genetic structure instead tracked breed identity and geography more strongly than function. In other words, a Spanish Mastiff was genetically more similar to nearby herding breeds than its guarding role alone would predict, and the strongest genetic divides followed regional and pedigree lines rather than the split between dogs that guard and dogs that herd. Analysis of molecular variance confirmed that most genetic variation resided within, rather than between, the working types.

The explanation, the authors argue, lies in the traditional pastoral practices of the Iberian Peninsula, above all transhumance. Transhumance is the seasonal movement of livestock between summer pastures in the mountains and winter lowlands, a practice that in Iberia dates back many centuries and once moved enormous flocks along dedicated droving roads called cañadas. Shepherds, flocks and dogs from different regions met regularly along these routes, creating repeated opportunities for dogs to be traded, loaned, mated or simply to travel between communities. Over generations, this mobility acted as a powerful gene flow engine, connecting dog populations across the peninsula and preventing any single region or working type from becoming genetically isolated.

The migration analyses bore this out. The researchers detected widespread signatures of historical gene flow among breeds, including gene flow that crossed the boundary between guarding and herding types. Haplotype sharing tests revealed significant shared ancestry between Iberian livestock dogs and other modern breeds, consistent with a history of exchange rather than isolation. Models of inferred migration events fitted the genetic data better than a strict tree-like divergence history, indicating that the breeds’ relationships are better described as a network of connected populations than as separate branches that split cleanly from a common ancestor.

Importantly, the study does not claim that breed differences are illusory. The data do show genetic structure associated with breed identity, meaning that the recognizable breeds of Iberia are real genetic entities to a meaningful degree. But the pattern suggests that this differentiation is relatively recent, layered on top of a deep background of shared diversity. The authors propose that traditional pastoral mobility maintained long-term genetic connectivity across the peninsula, while more recent breed formation, likely tied to the rise of formal breeding and closed studbooks in the modern era, produced the differentiation we see today. The genomic signature of that history persists even though transhumance has declined dramatically over the past century.

The broader implication is conceptually significant for evolutionary biology and conservation genetics alike. Specialization for distinct working roles, the study concludes, does not necessarily produce strong genome-wide divergence when population connectivity is maintained. Selection can shape behaviour, morphology and temperament without carving the genome into sharply separated clusters, provided that gene flow continues to mix variants across the population. This challenges a common assumption that functional specialization inevitably leads to reproductive isolation or deep genetic splits. It also highlights domestic animals as living archives of human cultural practices: the droving roads of medieval and early modern Iberia are still legible in the SNP patterns of dogs alive today.

For breeders and conservationists, the results carry practical weight. The high diversity and low inbreeding of Iberian livestock dogs suggest that these landraces are valuable reservoirs of genetic variation, both for their own long-term viability and potentially for the health of related breeds worldwide. Preserving the remaining traditional pastoral systems, the authors suggest, is not only a matter of cultural heritage but also of maintaining the ecological and genetic processes that shaped these animals. As wolves return to parts of Iberia and livestock guarding dogs regain practical importance, the dogs that once walked the cañadas may find their ancient jobs, and their ancient genes, newly relevant once more. The study, published open access in BMC Biology under DOI 10.1186/s12915-026-02744-y, stands as a striking reminder that genomes remember where people, and their dogs, have been.

Subject of Research: Population genomics of Iberian livestock guarding and herding dogs and the genetic legacy of historical pastoralism

Article Title: Genomic signatures of historical pastoralism in Iberian livestock dogs

Article References: Coutinho-Lima, D., Meneses-Ribeiro, M., Villegas, B., Alcaraz, L., López-Bao, J. V., Doadrio, I., & Godinho, R. (2026). Genomic signatures of historical pastoralism in Iberian livestock dogs. BMC Biology. https://doi.org/10.1186/s12915-026-02744-y

Image Credits: AI Generated

DOI: 10.1186/s12915-026-02744-y

Keywords: Iberian livestock dogs, population genetics, transhumance, pastoralism, livestock guarding dogs, herding dogs, gene flow, genetic diversity, microsatellites, SNPs, BMC Biology, dog breeds