蓖麻蚕核型多角体病毒解旋酶基因的克隆和序列分析

为了解柞蚕核型多角体病毒(Antheraea pernyinucleopolyhedrovirus,ApNPV)和蓖麻蚕核型多角体病毒(Philosamia cynthia riciniNPV,PcrNPV)在感染性及基因水平上的差别,克隆了PcrNPV解旋酶基因helicase,对该基因进行了测序及同源性分析。感染性试验表明,ApNPV对柞蚕和蓖麻蚕的感染率分别为78%和57%;而PcrNPV对蓖麻蚕的感染率为79%,但几乎不感染柞蚕。对PcrNPVhelicase分析的结果表明,该基因长度为3 639 bp,编码1 212个氨基酸(登录号:EU143371)。基因的同源性分析表明,PcrNPVhelicase与ApNPVhelicase的同源性最高,达98.6%,与苜蓿银纹夜蛾NPV(Autographa califorlicaNPV,AcNPV)helicase和家蚕NPV(BombyxmoriNPV,BmNPV)helicase的同源性最低,分别为58%和58.8%。PcrNPV和ApNPV的helicase基因7个保守功能域上的氨基酸序列均相同,仅在靠近DNA结合区螺旋-转角-螺旋结构处的第974位上有1个氨基酸不同,推测该位点可能与宿主域范围有关。

Cloning and Sequence Analysis of helicase Gene of Philosamia cynthia ricini nucleopolyhedrovirus

In order to identify the difference on the infection and genes between Antheraea pernyi nucleopolyhedrovirus(ApNPV) and Philosamia cynthia ricini NPV(PcrNPV),we carried out these experiments.The results of infection experiments indicated that ApNPV can infect both Antheraea pernyi and Philosamia cynthia ricini larvae,with the infectivity of 78% and 57%,respectively.However,PcrNPV can infect Philosamia cynthia ricini,with the infectivity of 79% and had almost no infectivity to the larva of Antheraea pernyi.The cloned PcrNPV helicase gene was 3 639 bp long and encoded a protein of 1 212 amino acids(Aceession number: EU143371).The homologous analysis results showed that PcrNPV helicase had the highest identity(98.6%) to that of ApNPV,and had the lowest identity to that of Autographa califorlica multiple NPV(AcMNPV) and Bombyx mori NPV(BmNPV),with the identity of 58% and 58.8%,respectively.The seven conserved motifs of ApNPV and PcrNPV helicase gene were completely ideutical,while only at the amino acid position 974,a different amino acid near the Ia motif and helix-turn-helix motif was found,suggesting that this position might be related with the host range.