Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
Virus Res. 2021 Jan 2;291:198200. doi: 10.1016/j.virusres.2020.198200. Epub 2020 Oct 17.
A molecular chaperone heat shock protein 90 (Hsp90) is required for efficient infection by several viruses. Hsp90 has been recently implicated in baculovirus infection, but its exact role remains obscure. This study investigated the effect of 17-N-allylamino-17-demethoxygeldanamycin (17-AAG), an Hsp90-specific inhibitor, on Bombyx mori nucleopolyhedrovirus (BmNPV) infection. The 17-AAG treatment significantly decreased the production of budded viruses and occlusion bodies in BmNPV-infected Bombyx mori cultured cells. Immunoblot and SDS-PAGE analyses showed that the expression of early and delayed early gene products, DBP and BRO, was delayed and dysregulated, and the very late gene product POLH was almost completely diminished. RT-qPCR experiments revealed that 17-AAG treatment did not affect initiation of the immediate early gene ie-1 expression, but the expression decreased by ∼50 % during the late stage of infection. 17-AAG treatment also decreased ie-1 promoter activity by ∼50 %. In addition, the expression of delayed early and late genes was dysregulated and inhibited, respectively. These results indicated that Hsp90 function is required for stable ie-1 transcription. Inhibiting Hsp90 function negatively affects ie-1 expression, resulting in dysregulation of delayed early genes and a severe decrease in late and very late gene expression.
一种分子伴侣热休克蛋白 90（Hsp90）对于几种病毒的有效感染是必需的。Hsp90 最近被牵连到杆状病毒感染，但它的确切作用仍不清楚。本研究调查了 17-N-烯丙基-17-去甲氧基格尔德霉素（17-AAG），一种 Hsp90 特异性抑制剂，对家蚕核型多角体病毒（BmNPV）感染的影响。17-AAG 处理显著降低了 BmNPV 感染家蚕细胞中芽生病毒和包埋体的产量。免疫印迹和 SDS-PAGE 分析表明，早期和延迟早期基因产物 DBP 和 BRO 的表达被延迟和失调，非常晚期基因产物 POLH 几乎完全消失。RT-qPCR 实验表明，17-AAG 处理不影响立即早期基因 ie-1 的表达起始，但在感染后期表达下降约 50%。17-AAG 处理还使 ie-1 启动子活性降低约 50%。此外，延迟早期和晚期基因的表达分别失调和受到抑制。这些结果表明 Hsp90 功能对于稳定的 ie-1 转录是必需的。抑制 Hsp90 功能会对 ie-1 表达产生负面影响，导致延迟早期基因失调和晚期和非常晚期基因表达严重下降。
