52 - The interaction between simian virus 40 and host DNA replication and repair proteins
Simian virus 40 is a small double-stranded DNA virus that relies upon mammalian host DNA replication proteins during the replication of its viral genome. Prior work has shown that during its replication, viral chromatin forms sub-nuclear replication foci which colocalize with many known host DNA repair proteins. Using immunofluorescence microscopy, Western blotting, and Southern blotting, we investigated the recruitment and activity of various host repair factors during viral replication. We found that while the protein recruitment of viral replication largely recapitulates that of host DNA replication, there are a few notable differences. In addition, we investigated the interaction between SV40 and the host DNA repair kinases ATM, ATR, and DNA-PKCS. During unperturbed viral replication, ATM and ATR (but not DNA-PKCS) kinase activity is required for successful replication. Inhibition of ATM kinase activity resulted in disrupted replication foci and differential protein recruitment, as well as the activation of DNA-PKCS. This work gives potential insight into the means by which mammalian cells may regulate the balance of their two main methods of double-strand break repair: homologous recombination and non-homologous end-joining, as well as increasing our understanding of SV40.