棉铃虫多核型多角体病毒v-cath同源基因的克隆及序列分析

为获得棉铃虫多核衣壳型多角体病毒(Helicoverpa armigera multiple nucleocapsid nucleopolyhedrovirus)基因组序列,采用随机克隆方法,建立HearMNPV的质粒基因文库,并通过对插入片段进行克隆鉴定和序列分析,获得编码组织蛋白酶基因v-cath。该基因阅读框为1026bp,共编码341个氨基酸。核苷酸和氨基酸同源性比较结果表明:HearMNPV的v-cath基因与蓓带夜蛾核型多角体病毒B(Mamestra configurata NPV-B)的同源性最高,而与苹果皮小卷蛾颗粒体病毒(Cydiapomonella GV CpGV)同源性最低,由此认为,杆状病毒科的v-cath基因在进化上存在2种进化方式:一类以点突变为主,基因长度变化不明显;另一类突变以小片段的碱基增减为特征。

Cloning and sequence analysis of v-cath gene of Helicoverpa armigera multiple nucleocapsid nucleopolyhedrovirus

In order to obtain the whole genome sequence of Helicoverpa armigera multiple nucleocapsid nucleopolyhedrovirus(HearMNPV),the genomic DNA of HearMNPV was partially digested by Sau3A I,and the plasmid vector pUC19 was fully digested by SalⅠ,and subsequently filled in by the Klenow fragment.After ligation and transformation,the inserted sequence showing high identity with that of the v-cath gene was acquired and identified.Its open reading frame(ORF)has 1 026 base pairs,encoding 341 amino acids.In comparison of its nucleotide and amino acid sequences with those of other baculovirus,HearMNPV v-cath shows the highest homology with that of Mamestra configurata NPV-B(MacoNPV-B),but the lowest homology with that of Cydia pomonella GV(CpGV).It is therefore suggested that HearMNPV v-cath had two ways of evolution:one is point mutation and the other is short nucleotide sequences.