The Baculoviridae is a large family of pathogens that are infectious for arthropods, particularly insects of the Lepidoptera. Nucleopolyhedroviruses (NPVs), a genus of Baculoviridae, have a large circular, supercoiled, and double-stranded DNA genome packaged into rod-shaped virions. The Bombyx mori NPV (BmNPV), an NPV pathogenic for B. mori, is known to potentially encode 136 proteins. Using the B. mori genome information, we found that 15 of 136 BmNPV proteins (11%) show significant similarity to the B. mori proteins. Among them, genes encoding nine proteins can be deleted in B. mori cultured cell line BmN by homologous recombination, indicating that these genes are dispensable for normal virus production. Interestingly, most of non-essential auxiliary genes encode proteins controlling host physiology at cellular and/or organismal levels: ecdysteroid UDP-glucosyltransferase inactivates an insect molting hormone ecdysone, protein tyrosine phosphatase is involved in wandering behavior at the late stage of infection, fibroblast growth factor induces host cell chemotaxis, and chitinase and cathepsin are required for postmortem host liquefaction. Deletion analysis of other non-essential genes also showed that three of them are viral pathogenicity factors for B. mori. These findings suggest that the modern lepidopteran baculovirus may have acquired auxiliary genes from an ancestral host insect to control host physiology and to increase the efficiency of virus transmission in nature.

中文翻译：

---

使用Bombyx基因组序列进行杆状病毒宿主同源物的全基因组调查。

杆状病毒科是对节肢动物，尤其是鳞翅目昆虫具有传染性的大量病原体。杆状病毒科的核多角体病毒（NPV）具有包装成杆状病毒体的大型圆形，超螺旋和双链DNA基因组。家蚕NPV（BmNPV）是一种导致家蚕致病的NPV，已知可能编码136种蛋白质。使用桑蚕芽孢杆菌基因组信息，我们发现136个BmNPV蛋白中有15个（11％）与桑蚕芽孢杆菌蛋白具有显着相似性。其中，编码9种蛋白质的基因可通过同源重组在桑蚕培养的细胞系BmN中缺失，这表明这些基因对于正常病毒的产生是可有可无的。有趣的是，大多数非必需的辅助基因都编码在细胞和/或生物水平上控制宿主生理的蛋白质：蜕皮甾体UDP-葡萄糖基转移酶使昆虫蜕皮激素蜕皮激素失活，蛋白酪氨酸磷酸酶在感染后期参与游荡行为，成纤维细胞生长因子诱导宿主细胞趋化，验尸宿主液化需要几丁质酶和组织蛋白酶。其他非必需基因的缺失分析也表明，其中三个是桑蚕的病毒致病因子。这些发现表明，现代鳞翅目杆状病毒可能已经从祖先的宿主昆虫中获得了辅助基因，以控制宿主的生理并提高病毒在自然界中的传播效率。成纤维细胞生长因子诱导宿主细胞趋化性，验尸宿主液化需要几丁质酶和组织蛋白酶。其他非必需基因的缺失分析也表明，其中三个是桑蚕的病毒致病因子。这些发现表明，现代鳞翅目杆状病毒可能已经从祖先的宿主昆虫中获得了辅助基因，以控制宿主的生理并提高病毒在自然界中的传播效率。成纤维细胞生长因子诱导宿主细胞趋化性，验尸宿主液化需要几丁质酶和组织蛋白酶。其他非必需基因的缺失分析也表明，其中三个是桑蚕的病毒致病因子。这些发现表明，现代鳞翅目杆状病毒可能已经从祖先的宿主昆虫中获得了辅助基因，以控制宿主的生理并提高病毒在自然界中的传播效率。