AcMNPV p95基因一段339 bp序列在病毒复制中的作用

杆状病毒苜蓿银纹夜蛾核型多角体病毒(AcMNPV)的p95基因编码的P95蛋白是病毒核衣壳的组成部分,也是虫体经口感染相关因子PIF(Per os Infectivity Factor)复合体的组成部分.前期研究表明,完整的P95蛋白对病毒的复制是非必需的,其中一段450bp的序列可以部分弥补p95基因的作用.本研究将p95基因一段339bp的片段(Core339,AcMNPV基因组位置:69 576~69 914bp)以正反两个方向分别插入到p95基因敲除的AcMNPV基因组中多角体位点的polyA之后,构建了两株重组病毒vP95K/EGFP/339+和vP95K/EGFP/339-.该两株病毒能在Sf9细胞中正常复制,复制水平与p95基因正常的AcEGFP相当,但复制速度较慢.重组病毒感染细胞的Western blot分析未检测到P95蛋白的表达.这一结果表明P95蛋白的缺失对病毒在细胞中的复制没有显著影响,但核心片段Core339对于病毒复制具有关键作用.

The Effect of a 339 bp-Sequence in AcMNPV p95 Gene on Virus Replication

The baculovirus Autographacalifornica multicapsid nucleopolyhedrovirus(AcMNPV) p95 gene encodes a protein that constitutes the virus nucleocapsid.It is also a component of the per os infectivity factor (PIF) complex,which is associated with viral infection of host insect.Early studies showed that the complete P95 protein is not essential for virus replication in vitro,and the presence of a 450 bp fragment could partially complement the function of p95.In this study,we identified a 339 bp fragment (Core339,69 576-69 914 bp in the AcMNPV genome),and inserted it in the downstream on the polyA signal sequence on the polyhedrin locus of the p95-deleted AcMNPV genome,to make recombinant viruses vP95K/EGFP/339 +-and vP95K/EGFP/339-.These viruses were capable to replicate normally,almost comparable to the control virus AcEGFP,though in a slower speed.Western blot analysis did not find any P95 protein in the infected cells.These results suggested that Core339 has an important role in virus replication in Sf9 cells while P95 protein itself was not essential in this respect.