Department of Molecular Genetics, Section of Virology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
J Gen Virol. 2010 May;91(Pt 5):1311-4. doi: 10.1099/vir.0.019307-0. Epub 2010 Jan 27.
Chandipura virus (CHPV) is an emerging human pathogen associated with acute encephalitis and is related closely to vesicular stomatitis virus (VSV), a prototype rhabdovirus. Here, we demonstrate that the RNA polymerase L protein of CHPV exhibits a VSV-like RNA:GDP polyribonucleotidyltransferase (PRNTase) activity, which transfers the 5'-monophosphorylated (p-) viral mRNA start sequence to GDP to produce a capped RNA, and that the conserved HR motif in the CHPV L protein is essential for the PRNTase activity. Interestingly, the CHPV L protein was found to form two distinct SDS-resistant complexes with the CHPV mRNA and leader RNA start sequences; mutations in the HR motif significantly reduced the formation of the former complex (a putative covalent enzyme-pRNA intermediate in the PRNTase reaction), but not the latter complex. These results suggest that the rhabdoviral L proteins universally use the active-site HR motif for the PRNTase reaction at the step of the enzyme-pRNA intermediate formation.
钱德普拉病毒（CHPV）是一种与急性脑炎相关的新兴人类病原体，与水疱性口炎病毒（VSV）密切相关，VSV 是一种典型的弹状病毒。在这里，我们证明 CHPV 的 RNA 聚合酶 L 蛋白表现出 VSV 样的 RNA：GDP 多聚核糖核苷酸转移酶（PRNTase）活性，将 5'-单磷酸化（p-）病毒 mRNA 起始序列转移到 GDP 上以产生加帽 RNA，并且 CHPV L 蛋白中的保守 HR 基序对于 PRNTase 活性是必不可少的。有趣的是，发现 CHPV L 蛋白与 CHPV mRNA 和前导 RNA 起始序列形成两种不同的 SDS 抗性复合物；HR 基序中的突变显著降低了前一种复合物的形成（PRNTase 反应中的假定共价酶-pRNA 中间物），但不降低后一种复合物的形成。这些结果表明，弹状病毒 L 蛋白普遍在酶-pRNA 中间物形成步骤中使用活性位点 HR 基序进行 PRNTase 反应。
