State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, 510275, China.
Sci Rep. 2017 Aug 10;7(1):7823. doi: 10.1038/s41598-017-08437-5.
Baculovirus nucleocapsids egress from the nucleus primarily via budding at the nuclear membrane. The nuclear lamina underlying the nuclear membrane represents a substantial barrier to nuclear egress. Whether the nuclear lamina undergoes disruption during baculovirus infection remains unknown. In this report, we generated a clonal cell line, Sf9-L, that stably expresses GFP-tagged Drosophila lamin B. GFP autofluorescence colocalized with immunofluorescent anti-lamin B at the nuclear rim of Sf9-L cells, indicating GFP-lamin B was incorporated into the nuclear lamina. Meanwhile, virus was able to replicate normally in Sf9-L cells. Next, we investigated alterations to the nuclear lamina during baculovirus infection in Sf9-L cells. A portion of GFP-lamin B localized diffusely at the nuclear rim, and some GFP-lamin B was redistributed within the nucleus during the late phase of infection, suggesting the nuclear lamina was partially disrupted. Immunoelectron microscopy revealed associations between GFP-lamin B and the edges of the electron-dense stromal mattes of the virogenic stroma, intranuclear microvesicles, and ODV envelopes and nucleocapsids within the nucleus, indicating the release of some GFP-lamin B from the nuclear lamina. Additionally, GFP-lamin B phosphorylation increased upon infection. Based on these data, baculovirus infection induced lamin B phosphorylation and disruption of the nuclear lamina.
杆状病毒核衣壳主要通过核膜出芽从细胞核中逸出。核膜下的核板是核出芽的一个主要障碍。杆状病毒感染过程中核板是否会发生破坏尚不清楚。在本报告中，我们生成了一个稳定表达 GFP 标记的果蝇 lamin B 的克隆细胞系 Sf9-L。GFP 自发荧光与 Sf9-L 细胞核周的抗 lamin B 免疫荧光共定位，表明 GFP-lamin B 被整合到核板中。同时，病毒能够在 Sf9-L 细胞中正常复制。接下来，我们研究了杆状病毒感染期间 Sf9-L 细胞中核板的变化。一部分 GFP-lamin B 在核周弥散定位，而在感染后期 GFP-lamin B 在内核中重新分布，表明核板部分被破坏。免疫电子显微镜显示 GFP-lamin B 与病毒质基质的电子致密边缘、核内微泡以及核内 ODV 包膜和核衣壳之间存在关联，表明部分 GFP-lamin B 从核板中释放出来。此外，感染后 GFP-lamin B 的磷酸化增加。基于这些数据，杆状病毒感染诱导 lamin B 磷酸化和核板破坏。
