MODULATION OF BOVINE PAPILLOMAVIRUS DNA-REPLICATION BY PHOSPHORYLATION OF THE VIRAL E1 PROTEIN

E1 is the DNA replication origin recognition protein for bovine papill omavirus (BPV), and it carries out enzymatic functions required for in itiation of viral DNA replication. Cellular mechanisms likely play a r ole in regulating BPV DNA replication. We are investigating the role o f phosphorylation of E1 on viral replication in vivo and on E1 activit y in vitro. Serine 109 is a phosphoacceptor in vivo and is targeted by protein kinase A and protein kinase C in vitro. A viral genome carryi ng a serine 109 to alanine mutation replicates more efficiently than w ild-type in vivo in a transient replication assay. Furthermore, purifi ed mutant protein, while having wild-type levels of ATPase activity, i s able to bind more origin-containing DNA than wild-type E1. Phosphory lation therefore appears to play a selective role in modulating a spec ific E1 function during viral DMA replication. (C) 1997 Academic Press .