Zanardi T A, Stanley C M, Saville B M, Spacek S M, Lentz M R
Department of Biochemistry and Biophysics, Texas A&M University, College Station 77843-2128, USA.
Virology. 1997 Feb 3;228(1):1-10. doi: 10.1006/viro.1996.8375.
E1 is the DNA replication origin recognition protein for bovine papillomavirus (BPV), and it carries out enzymatic functions required for initiation of viral DNA replication. Cellular mechanisms likely play a role in regulating BPV DNA replication. We are investigating the role of phosphorylation of E1 on viral replication in vivo and on E1 activity 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 carrying a serine 109 to alanine mutation replicates more efficiently than wild-type in vivo in a transient replication assay. Furthermore, purified mutant protein, while having wild-type levels of ATPase activity, is able to bind more origin-containing DNA than wild-type E1. Phosphorylation therefore appears to play a selective role in modulating a specific E1 function during viral DNA replication.
E1是牛乳头瘤病毒（BPV）的DNA复制起始识别蛋白，它执行病毒DNA复制起始所需的酶促功能。细胞机制可能在调节BPV DNA复制中发挥作用。我们正在研究E1磷酸化在体内病毒复制和体外E1活性中的作用。丝氨酸109在体内是磷酸化位点，在体外被蛋白激酶A和蛋白激酶C靶向作用。在瞬时复制试验中，携带丝氨酸109突变为丙氨酸的病毒基因组在体内比野生型复制更有效。此外，纯化的突变蛋白虽然具有野生型水平的ATP酶活性，但比野生型E1能结合更多含起始位点的DNA。因此，磷酸化似乎在病毒DNA复制过程中调节特定E1功能方面发挥着选择性作用。
