小菜蛾颗粒体病毒晚期表达因子基因的功能分析

小菜蛾颗粒体病毒(Plutella xylostella granulovirus,PlxyGV)基因组含有15个杆状病毒晚期表达因子(Lateexpression factor,lef)基因同源物。PlxyGV的14个lef基因(不包括ie-0)预期编码产物与苜蓿银纹夜蛾核多角体病毒(Autographa californica multicapsid nucleopolyhedrovirus,AcMNPV)LEF蛋白的序列相似度为13%～53%。其中,LEF-8、LEF-9和P47在两种病毒之间的相似度较高,分别为49%、53%和46%。为了研究不同杆状病毒种间lef基因的功能相关性,验证PlxyGVlef基因的功能,本文利用AcMNPV的一个瞬时表达实验系统测试PlxyGVlef基因在Sf9细胞中激活AcMNPV晚期启动子控制的报告基因表达的能力。实验结果显示,在其它AcMNPVlef基因都存在的情况下,PlxyGVlef-2能够部分替代AcMNPVlef-2的活性。序列对比结果显示Plx-yGV LEF-2的C端末比其它GV和鳞翅目NPV的LEF-2分别多出约100aa和70aa。

Functional Analysis of the Late Expression Factor Genes of Plutella Xylostella Granulovirus

Plutella xylostella granulovirus(PlxyGV) contains homologs of 15 Autographa californica MNPV(AcMNPV) late expression factor(lef) genes.The prospective products of 14 PlxyGV lef genes(ie-0 is not included) share 13%~53% amino acid similarity with their corresponding homologs of AcMNPV,among which LEF-9,LEF-8 and P47,three subunits of the virus-encoded RNA polymerase,share 49%,53% and 46% sequence identity,respectively.In this study,an established transient expression system was used to test the ability of the PlxyGV LEFs to activate an AcMNPV vp39 promoter-driven reporter gene in SF9 cells.It was shown that PlxyGV lef-2 replaced the corresponding AcMNPV gene and exhibited partial activity in the context of the remaining set of AcMNPV lefs.PlxyGV LEF-2 was found to contain additional 100aa and 70aa at the C-terminus in comparison with the LEF-2 of other GVs and lepidopteran NPVs respectively.