Department of Cancer Biology, 314 Biomedical Research Building, 421 Curie Blvd., School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6142, USA.
J Virol. 2010 Jul;84(14):7005-17. doi: 10.1128/JVI.00719-10. Epub 2010 May 19.
The process of assembly and egress of human cytomegalovirus (HCMV) virions requires significant morphological alterations of the nuclear and cytoplasmic architecture. In the studies presented we show that the nuclear periphery is dramatically altered, especially near the cytoplasmic assembly compartment, where the nuclear lamina is specifically rearranged, the outer nuclear membrane is altered, and the nucleus becomes permeable to large molecules. In addition, the tethering of the inner and outer nuclear membranes is lost during infection due to a decrease in levels of the SUN domain proteins. We previously demonstrated that the endoplasmic reticulum protein BiP functions as a component of the assembly compartment and disruption of BiP causes the loss of assembly compartment integrity. In this study we show that the depletion of BiP, and the loss of assembly compartment integrity, results in the loss of virally induced lamina rearrangement and morphology of the nucleus that is characteristic of HCMV infection. BiP functions in lamina rearrangement through its ability to affect lamin phosphorylation. Depletion of BiP and disruption of the assembly compartment result in the loss of lamin phosphorylation. The dependency of lamin phosphorylation on BiP correlates with an interaction between BiP and UL50. Finally, we confirm previous data (S. V. Indran, M. E. Ballestas, and W. J. Britt, J. Virol. 84:3162-3177, 2010) suggesting an involvement of dynein in assembly compartment formation and extend this observation by showing that when dynein is inhibited, the nuclear morphology characteristic of an HCMV infection is lost. Our data suggest a highly integrated assembly-egress continuum.
人类巨细胞病毒(HCMV)病毒粒子的组装和出芽过程需要细胞核和细胞质结构的显著形态改变。在本研究中,我们表明核周区域发生了巨大变化,特别是在细胞质组装隔室附近,核板层被特异性重排,外核膜发生改变,核变得可通透大分子。此外,由于 SUN 结构域蛋白水平降低,感染过程中外核膜与内核膜的连接丢失。我们之前证明内质网蛋白 BiP 作为组装隔室的组成部分发挥作用,BiP 的破坏导致组装隔室完整性的丧失。在这项研究中,我们表明 BiP 的耗竭以及组装隔室完整性的丧失,导致病毒诱导的板层重排和 HCMV 感染特征性核形态的丧失。BiP 通过影响核纤层蛋白磷酸化来调节板层重排。BiP 的耗竭和组装隔室的破坏导致核纤层蛋白磷酸化的丧失。依赖 BiP 的核纤层蛋白磷酸化与 BiP 和 UL50 之间的相互作用相关。最后,我们证实了先前的数据(S. V. Indran、M. E. Ballestas 和 W. J. Britt,J. Virol. 84:3162-3177, 2010)表明 dynein 参与组装隔室的形成,并通过显示当 dynein 被抑制时,丧失了 HCMV 感染的典型核形态,扩展了这一观察结果。我们的数据表明存在高度整合的组装-出芽连续体。