In the realm of modern medicine, RNA molecules have rapidly ascended to a position of paramount significance, underpinning breakthroughs from vaccines and diagnostics to cutting-edge gene-based therapies. Despite their critical role, a persistent technical hurdle has constrained the full exploitation of RNA’s potential: the swift, precise, and adaptable synthesis of RNA strands. Addressing this challenge is essential for the advancement of next-generation biomedical applications, where customized and chemically modified RNA molecules play a pivotal role. Recently, a multidisciplinary research team led by Professor John Chaput at the University of California, Irvine, has made a landmark advance by engineering a novel enzyme capable of synthesizing RNA with unprecedented efficiency and fidelity.
This breakthrough centers on an engineered polymerase enzyme, dubbed C28, which fundamentally redefines the boundaries of RNA synthesis technology. Unlike natural DNA polymerases that are evolutionarily programmed to reject RNA templates due to structural incompatibilities, C28 exhibits a remarkable capacity to generate RNA at speeds comparable to those found in biological systems while sustaining exceptional accuracy. The capacity to copy lengthy RNA sequences reliably without plethora of errors is critical in biotechnological applications ranging from mRNA vaccine production to synthetic biology and therapeutic development.
What sets this discovery apart is the innovative method employed to create C28. Traditional enzyme engineering often focuses on rational design, targeting the enzyme’s active site directly to alter substrate specificity. However, Chaput’s team eschewed this conventional strategy, opting instead for directed evolution—a process mimicking natural selection in the laboratory. By leveraging a high-throughput, single-cell screening platform capable of evaluating millions of polymerase variants concurrently, the researchers facilitated the emergence of C28, an enzyme characterized by dozens of mutations dispersed throughout its entire protein structure rather than concentrated in the active site.
The engineering strategy was anchored in homologous recombination, combining genes from related polymerases to generate a vast diversity of enzyme variants. This method enabled the capture of synergistic mutations enhancing overall enzyme function. After just a few rounds of iterative selection, the process yielded C28, an enzyme whose performance defied existing paradigms. The evolved polymerase not only synthesizes RNA at near-natural speeds but also excels in reverse transcription—efficiently copying RNA back into complementary DNA strands—making it a dual-function enzyme with versatile research and clinical applications.
Moreover, C28 is adept at producing hybrid DNA-RNA molecules via standard polymerase chain reaction (PCR) techniques, a capability that broadens its utility in nucleic acid manipulation and molecular diagnostics. Significantly, the enzyme readily accepts chemically modified nucleotides—building blocks used in state-of-the-art mRNA vaccines and RNA-based therapeutic modalities—without compromising efficiency or accuracy. This tolerance for modified substrates enhances its relevance for pharmaceutical manufacturing processes, where chemical modifications improve RNA stability and functionality in vivo.
The implications of the C28 polymerase extend beyond practical uses. This achievement robustly exemplifies the power of directed evolution as a tool to transcend inherent biological limitations and harness enzyme plasticity. The work underscores a profound insight that enzyme structures possess a latent adaptability greater than traditionally anticipated, affording researchers the ability to discover novel molecular functionalities through non-intuitive evolutionary pathways rather than solely relying on prior biochemical knowledge.
John Chaput emphasizes the transformative nature of this capability, highlighting that directed evolution can produce molecular machines with tailored properties, unlocking fresh opportunities within RNA biology, synthetic biology, and biomedical innovation. This shift introduces a new era of molecular tools that can accelerate discovery and development processes in life sciences, particularly where synthetic RNA molecules are central.
The journey to create C28 also showcases the integration of cutting-edge technologies, including single-cell screening that allows exhaustive sampling of mutational landscapes, thereby accelerating the evolutionary search for optimal enzyme variants. This approach enhances reproducibility and scalability, positioning it as an indispensable method for future enzyme engineering campaigns targeting a wide range of molecular functions previously deemed intractable.
Beyond its immediate scientific contributions, the C28 polymerase exemplifies a societal impact dimension by underpinning advancements in vaccine technology development pipelines, expanding diagnostic tools, and enabling next-generation nucleic acid therapeutics. The increased accessibility to robust, versatile RNA polymerases can catalyze cost reductions and efficiency improvements in manufacturing, ultimately benefiting public health worldwide.
Supporting this pioneering research, the U.S. National Science Foundation provided critical funding, underscoring the importance of sustained investment in fundamental biomedical research and innovative technologies. The multidisciplinary efforts engaged scientists specialized in pharmaceutical sciences, molecular biology, and evolutionary biochemistry, symbolizing the collaborative nature of contemporary scientific breakthroughs.
The University of California, Irvine, home to this research, continues to reinforce its reputation as a leader in academic excellence and innovation, fostering an environment where theoretical concepts can be translated into transformative technologies. Professor Chaput’s team exemplifies this dynamic, achieving not only a technical triumph in enzyme engineering but also inspiring future avenues for synthetic biomolecular design.
In summary, the engineered RNA polymerase C28 represents a transformative leap forward in molecular biotechnology, combining evolutionary ingenuity with practical applicability. Its capacity to synthesize RNA efficiently and accurately, accept modified substrates, and perform multiple nucleic acid synthesis functions positions it as a cornerstone tool for the accelerating fields of RNA research and therapeutic development. As RNA continues to shape the frontier of biomedical science, innovations such as C28 will likely serve as catalysts driving breakthroughs across drug development, synthetic biology, and personalized medicine.
Subject of Research:
Enzyme engineering for RNA synthesis; development of a novel polymerase capable of RNA synthesis, reverse transcription, and DNA-RNA hybrid generation.
Article Title:
Rapid evolution of a highly efficient RNA polymerase by homologous recombination
News Publication Date:
February 9, 2026
Web References:
https://www.nature.com/articles/s41589-025-02124-7
References:
Chaput, J., et al. Rapid evolution of a highly efficient RNA polymerase by homologous recombination. Nature Chemical Biology, Published January 7, 2026.
Keywords:
RNA synthesis, enzyme engineering, directed evolution, RNA polymerase, homologous recombination, RNA therapeutics, mRNA vaccines, reverse transcription, synthetic biology, molecular biotechnology
