家蚕浓核病毒DNV-3（中国株）的VD2基因组序列分析

浓核病毒BmDNV-3(中国株)基因组中含有两种不同的单链线形DNA分子(VD1,VD2)。该病毒的VD2被分离、纯化、克隆到pUC119载体上,并完成了VD2全基因组序列的测定。序列分析显示:VD2全基因组长为6022个核苷酸,末端拥有524个核苷酸反向重复序列(ITRs)。VD2基因组正链含有2个大的开放阅读框,负链含有1个小的开放阅读框。计算机分析推测该基因组正链上开放阅读框(ORF1)及负链上开放阅读框(ORF3)主要编码病毒的非结构蛋白,而正链上开放阅读框(ORF2)主要编码病毒的结构蛋白。比较BmDNV-3 VD2和BmDNV-2(Yamanashiisolate)VD2基因组全序列,两者同源性达97.7%,并且有132个碱基的替代1、1个碱基的删除和2个碱基插入。研究结果显示BmDNV-3 VD2和BmDNV-2 VD2有很近的亲缘关系,但也发生一定的变异,这为更好地理解浓核病毒种类的多样性,也为研究家蚕浓核病毒进化提供了有益的线索。

Complete nucleotide sequence analysis of Bombyx mori densonucleosis virus type 3 VD2(China isolate)

The genome of Bombyx mori densonucleosis virus type 3(China isolate) contains two kinds different single-stranded linear DNA molecules(VD_1,VD_2).The VD_2 was purified and cloned into the pUC119 vector,and the complete nucleotide sequence of VD_2 was determined.Sequence analysis showed that the VD_2 genome sequence consisted of 6022 nts,including inverted terminal repeats(ITRs) of 524 nts.In the viral genome,two major open reading frames(ORF1 and ORF2) in the plus strand and one minor ORF(ORF3) in the complementary strand were identified.Computer analysis suggested the plus stand ORF1 and the minus strand ORF3 most likely encode the major nonstructural protein,while the plus stand ORF2 most likely encodes the major structural protein.Comparing the complete genome sequence of BmDNV-3 VD_2 with that of BmDNV-2 VD_2(Yamanashi isolate) demonstrated that they shared 97.7% genome sequence in the VD_2 region,with substitutions of 132 nucleotides,deletions of 11 nucleotides and insertions of 2 nucleotides in the VD_2 region of BmDNV-3.The results suggested that BmDNV-3 is closely related to BmDNV-2,but with some differences,giving a better understanding about the variation of the viruses and providing clues to their evolution.