Zuidema D, Klinge-Roode E C, van Lent J W, Vlak J M
Department of Virology, Agricultural University, Wageningen, The Netherlands.
Virology. 1989 Nov;173(1):98-108. doi: 10.1016/0042-6822(89)90225-0.
An Autographa californica nuclear polyhedrosis virus (AcMNPV)-specific protein of 34 kDa (pp34) is shown to be involved in the morphogenesis of the polyhderal envelope of baculoviruses. The region of the AcMNPV genome encompassing EcoRI-H and -S (map positions 82.6-85.8) contains five open reading frames (ORFs) forming one transcriptional unit. The bacterial beta-galactosidase (lacZ) gene was inserted in phase with the N-terminal 12 amino acids of ORF3, thereby intervening this gene. A recombinant (AcMNPV/p34DZ5) was selected by the expression of lacZ (blue plaques). Protein analysis by SDS-PAGE and immunoblotting indicated that Spodoptera frugiperda cells infected with the recombinant lacked pp34. Electron microscopy of recombinant-infected cells showed that the electron-dense "spacers", normally present in wild-type AcMNPV-infected cells, were also absent. These results indicated that pp34 is dispensable for nonoccluded virus replication and is involved in the morphogenesis of the polyhedral envelope. The recombinants were infectious to fourth instar larvae of Spodoptera exigua. Recombinant polyhedra were more sensitive to weak alkali. This supports the hypothesis that the absence of the polyhedral envelope and the efficient release of occluded virions are responsible for the increased virulence of polyhedral envelope negative mutants.
一种34 kDa的苜蓿银纹夜蛾核型多角体病毒（AcMNPV）特异性蛋白（pp34）被证明参与杆状病毒多面体包膜的形态发生。AcMNPV基因组中包含EcoRI-H和-S的区域（图谱位置82.6 - 85.8）含有五个开放阅读框（ORF），形成一个转录单元。将细菌β-半乳糖苷酶（lacZ）基因与ORF3的N端12个氨基酸同相位插入，从而干扰该基因。通过lacZ的表达（蓝色噬菌斑）筛选出重组体（AcMNPV/p34DZ5）。通过SDS-PAGE和免疫印迹进行的蛋白质分析表明，感染重组体的草地贪夜蛾细胞缺乏pp34。对重组体感染细胞的电子显微镜观察表明，野生型AcMNPV感染细胞中通常存在的电子致密“间隔物”也不存在。这些结果表明，pp34对于非包涵体病毒复制是可有可无的，并且参与多面体包膜的形态发生。重组体对甜菜夜蛾四龄幼虫具有感染性。重组多面体对弱碱更敏感。这支持了以下假设：多面体包膜的缺失和包涵体病毒粒子的有效释放是多面体包膜阴性突变体毒力增加的原因。
