Cohen Sarah, Panté Nelly
Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4.
J Gen Virol. 2005 Dec;86(Pt 12):3243-3252. doi: 10.1099/vir.0.80967-0.
Parvoviruses are small DNA viruses that replicate in the nucleus of their host cells. It has been largely assumed that parvoviruses enter the nucleus through the nuclear pore complex (NPC). However, the details of this mechanism remain undefined. To study this problem, the parvovirus Minute virus of mice (MVM) was microinjected into the cytoplasm of Xenopus oocytes and a transmission electron microscope was used to visualize the effect of the virus on the host cell. It was found that MVM caused damage to the nuclear envelope (NE) in a time- and concentration-dependent manner. Damage was predominantly to the outer nuclear membrane and was often near the NPCs. However, microinjection experiments in which the NPCs were blocked showed that NE damage induced by MVM was independent of the NPC. To address the question of whether this effect of MVM is specific to the NE, purified organelles were incubated with MVM. Visualization by electron microscopy revealed that MVM did not affect all intracellular membranes. These data represent a novel form of virus-induced damage to host cell nuclear structure and suggest that MVM is imported into the nucleus using a unique mechanism that is independent of the NPC, and involves disruption of the NE and import through the resulting breaks.
细小病毒是在宿主细胞核内复制的小型DNA病毒。人们大多认为细小病毒通过核孔复合体（NPC）进入细胞核。然而，这一机制的细节仍不明确。为研究该问题，将小鼠细小病毒（MVM）显微注射到非洲爪蟾卵母细胞的细胞质中，并使用透射电子显微镜观察病毒对宿主细胞的影响。结果发现，MVM以时间和浓度依赖的方式对核膜（NE）造成损伤。损伤主要发生在外核膜，且常靠近核孔复合体。然而，阻断核孔复合体的显微注射实验表明，MVM诱导的核膜损伤与核孔复合体无关。为解决MVM的这种作用是否对核膜具有特异性这一问题，将纯化的细胞器与MVM一起孵育。电子显微镜观察显示，MVM并不影响所有细胞内膜。这些数据代表了病毒诱导的宿主细胞核结构损伤的一种新形式，并表明MVM通过一种独立于核孔复合体的独特机制进入细胞核，该机制涉及核膜的破坏以及通过由此产生的破裂处进入细胞核。
