Cellular and viral RNA polymerases: evolutionary insights into eukaryotic origins

Area of Science:

• Virology
• Evolutionary Biology
• Molecular Biology

Background:

• Nucleocytoplasmic large DNA viruses (NCLDVs) possess unique multi-subunit RNA polymerases (msRNAPs).
• These viral enzymes challenge traditional models of viral evolution and eukaryotic origins.
• Understanding NCLDV msRNAPs offers insights into the Last Eukaryotic Common Ancestor (LECA).

Purpose of the Study:

• To review the structural and functional characteristics of NCLDV msRNAPs.
• To synthesize evidence for virus-driven evolution of RNA polymerases.
• To evaluate hypotheses regarding the role of viruses in eukaryogenesis.

Main Methods:

• Phylogenetic analysis of NCLDV and eukaryotic RNA polymerases.
• Structural comparisons of viral and cellular RNA polymerase catalytic cores.
• Review of existing literature on viral gene regulation and eukaryogenesis.

Main Results:

• NCLDV msRNAP catalytic cores share ancient evolutionary origins with eukaryotic counterparts.
• Evidence suggests ancient gene transfers involving viruses shaped LECA.
• NCLDV RNAPs retain core cellular architecture but are adapted for viral needs.

Conclusions:

• NCLDVs are pivotal in understanding eukaryotic origins and evolution.
• Viral msRNAPs provide insights into enzyme adaptability and gene regulation.
• Viruses act as evolutionary collaborators, bridging virology, evolutionary biology, and synthetic biology.