DNA Polymerase Family B Reveals Novel Viral Diversity and Reflects Infection Strategy

• Zaina Punter, Applied Molecular Biology & Biotechnology, University of Delaware

• Shawn Polson, Computer & Information Sciences, University of Delaware

There are 10^30 bacteriophages (phages)—viruses that infect bacteria—in the world’s oceans, making them the most abundant biological entity on Earth. Phage maintain a singular central function of genome replication through lytic or temperate infection of their bacterial host, and the outcomes of phage infection significantly impact bacterial communities and nutrient cycling. The Viral Ecology and Informatics Laboratory uses phage replication proteins, such as DNA polymerases, as markers of bacteriophage lifestyle. DNA Polymerase B (PolB) exhibits potential as a viral marker gene, given that it is important to viral biology, is well-represented in publicly available databases, and is encoded by ecologically important groups, such as cyanophage, which infect photosynthetic cyanobacteria. This research project characterizes conserved domains and active sites in PolB and uses this knowledge to validate PolB in environmental samples. Putative PolB are retrieved from a collection of environmental viral genomes based on similarity to reference sequences and validated based on domains relating to PolB. Conserved domains and motifs are identified based on literature review and multi-sequence alignments. Analysis of co-occurring replication proteins reveals patterns between PolB classes.  Future research will explore the diversity and abundance of PolB-carrying viral populations and their impacts on host communities and ecosystems.