Transient Viral DNA Replication and Repression of Viral Transcription Are Supported by the C-Terminal Domain of the Bovine Papillomavirus Type 1 E1 Protein

The bovine papillomavirus type 1 E1 protein is important for viral DNA replication and transcriptional repression. It has been proposed that the full-length E1 protein consists of a small N-terminal and a larger C-terminal domain. In this study, it is shown that an E1 polypeptide containing residues 132 to 605 (which represents the C-terminal domain) is able to support transient viral DNA replication, although at a level lower than that supported by the wild-type protein. This domain can also repress E2-mediated transactivation from the P89 promoter as well as the wild-type E1 protein can.

牛乳头瘤病毒1型（bovine papillomavirus type 1）E1蛋白在病毒DNA复制与转录抑制过程中发挥关键作用。现有研究提出，全长E1蛋白由一个小型N端结构域与一个较大的C端结构域组成。本研究证实，包含132至605位氨基酸残基（对应该C端结构域）的E1多肽可支持瞬时病毒DNA复制，尽管其复制水平低于野生型E1蛋白所支持的程度。该结构域同样能够抑制E2介导的P89启动子反式激活，其效果与野生型E1蛋白相当。