Evgenii Protasov (@evgenii-protasov.bsky.social)

Cellular and viral RNA polymerases: evolutionary insights into eukaryotic origins Nucleocytoplasmic large DNA viruses (NCLDVs) encode multi-subunit RNA polymerases (msRNAPs) that challenge conventional views of viral evolution. Phylogenetic and structural studies reveal that NCLDV RNAP catalytic cores share deep evolutionary roots with eukaryotic counterparts, implicating ancient gene transfers that shaped the last eukaryotic common ancestor (LECA), underscoring NCLDVs’ pivotal role in eukaryotic origins. NCLDV RNAP retains the fundamental architecture of cellular RNAPs while evolving and adapting for viral gene regulation. This review summarizes structural and functional divergences between viral and cellular RNAPs, synthesizes evidence for virus-driven RNAP evolution, and evaluates emerging hypotheses of viral eukaryogenesis. Viewing viruses as evolutionary collaborators offers new insights into RNAP adaptability and bridges virology, evolutionary biology, and synthetic biology across diverse biological contexts. https://www.cell.com/trends/microbiology/abstract/S0966-842X(25)00335-X