Bideshi D K, Hice R H, Ge B, Federici B A
Graduate Program in Genetics, University of California, Riverside 92521, USA.
J Gen Virol. 1998 May;79 ( Pt 5):1309-19. doi: 10.1099/0022-1317-79-5-1309.
A putative DNA helicase gene from the granulovirus of Trichoplusia ni (TnGV) was cloned, sequenced, and compared with the corresponding gene of several multinucleocapsid nucleopolyhedroviruses (MNPVs) including those from Autographa californica (AcMNPV), Orgyia pseudotsugata (OpMNPV), Bombyx mori (BmNPV), and Spodoptera exigua (SeMNPV). The TnGV helicase gene (p137) encoded a helicase of 1158 amino acids with a predicted mass of 137 kDa. Comparison of p137 with AcMNPV p143 revealed 44.5% identity at the nucleotide level, and, respectively, 28.6% identity and 53.0% similarity at the amino acid level. Similar levels of identity and similarity were obtained when TnGV p137 was compared with the corresponding helicase genes of BmNPV, OpMNPV and SeMNPV. Using an antisense probe made from an internal 1.6 kb region of p137, a major transcript of approximately 3600 nt was detected by Northern blot analysis in fat body tissue from TnGV-infected larvae of T. ni. As both TnGV and AcMNPV replicate efficiently in larvae of T. ni, these results demonstrate that baculovirus putative DNA helicases which have diverged markedly can function efficiently in the same host. Three genes flanking TnGV p137, designated ORF68, ORF219 and ORF157, corresponded in order and orientation with AcMNPV ORFs 93, 94 and 96. However, the amino acid similarity between corresponding genes ranged from only 50.4 to 62.5%, providing further evidence that related baculovirus proteins which have diverged markedly can function efficiently in the same host.
克隆并测序了来自粉纹夜蛾颗粒体病毒（TnGV）的一个假定的DNA解旋酶基因，并将其与几种多核衣壳核多角体病毒（MNPV）的相应基因进行了比较，这些病毒包括苜蓿银纹夜蛾核多角体病毒（AcMNPV）、云杉芽卷叶蛾核多角体病毒（OpMNPV）、家蚕核多角体病毒（BmNPV）和甜菜夜蛾核多角体病毒（SeMNPV）。TnGV解旋酶基因（p137）编码一个由1158个氨基酸组成的解旋酶，预测分子量为137 kDa。p137与AcMNPV p143在核苷酸水平上的同一性为44.5%，在氨基酸水平上的同一性分别为28.6%，相似性为53.0%。当将TnGV p137与BmNPV、OpMNPV和SeMNPV的相应解旋酶基因进行比较时，也获得了相似水平的同一性和相似性。使用由p137内部1.6 kb区域制备的反义探针，通过Northern印迹分析在TnGV感染的粉纹夜蛾幼虫的脂肪体组织中检测到一个约3600 nt的主要转录本。由于TnGV和AcMNPV都能在粉纹夜蛾幼虫中高效复制，这些结果表明，已显著分化的杆状病毒假定DNA解旋酶可以在同一宿主中高效发挥功能。位于TnGV p137侧翼的三个基因，分别命名为ORF68、ORF219和ORF157，在顺序和方向上与AcMNPV的ORF93、ORF94和ORF96相对应。然而，相应基因之间的氨基酸相似性仅在50.4%至62.5%之间，这进一步证明，已显著分化的相关杆状病毒蛋白可以在同一宿主中高效发挥功能。
