油桐尺蛾核型多角体病毒lef-8基因结构及系统进化分析

The Structural and Phylogenetic Analysis of Late Expression Factor 8( lef-8) Gene in Buzura suppressaria Nuclear Polyhedrosis Virus

lef-8基因作为杆状病毒重要的早期表达基因,编码病毒RNA聚合酶的最大亚基。本文通过对油桐尺蛾核型多角体病毒lef-8基因进行测序,对其基因结构及其在杆状病毒中的系统进化进行了分析。发现lef-8基因在油桐尺蛾核型多角体病毒中编码区长2 634 bp,编码877个氨基酸。在5’-UTR区具有可能为其启动子及转录起始位点的信号序列,在3’-UTR区具有加尾信号序列,但这些序列的具体功能还有待进一步研究。其蛋白序列与常见的模式NPV同源性较低,但具有共同的签名序列。通过对杆状病毒lef-8基因的系统进化分析,发现颗粒体病毒和核型多角体病毒明显分为两支,而核型多角体病毒中又明显分为4个分支,其进化关系在很大程度上与其寄主的进化关系相关。

Late expression factor 8 （lef-8） gene is an early polymerase in baculovirus. The authors sequenced the lef-8 （BsNPV）. It had 2 634 bp coding region and encoding 877 expression gene, and codes the largest subunit of RNA gene of Buzura suppressaria nuclear polyhedrosis virus amino acid residues. Some signal sequences were found in untranslated region （UTR） ： possible promoter and transcription initiation site were found in 5＇ -UTR, and a putative polyadenylation signal sequence was found in 3＇ -UTR. But whether they had substantial function needs further research. The protein sequence of lef-8 gene in BsNPV was low homologous to model NPYs. But they had nearly the same signal sequence. By phylogenetic analysis of lef-8 gene in baculovirus, it was found that the nuclear polyhedrosis ＂Arus （NPV） and the granulosis ,titus （GV） was separated ob,dously to two branches, while the NPV broke into 4 branches. And evolutionary relationship in baculovirus was largely associated with its host.