Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4.
J Struct Biol. 2012 Jan;177(1):90-8. doi: 10.1016/j.jsb.2011.11.006. Epub 2011 Nov 12.
Baculoviruses are one of the largest viruses that replicate in the nucleus of their host cells. During an infection the capsid, containing the DNA viral genome, is released into the cytoplasm and delivers the genome into the nucleus by a mechanism that is largely unknown. Here, we used capsids of the baculovirus Autographa californica multiple nucleopolyhedrovirus in combination with electron microscopy and discovered this capsid crosses the NPC and enters into the nucleus intact, where it releases its genome. To better illustrate the existence of this capsid through the NPC in its native conformation, we reconstructed the nuclear import event using electron tomography. In addition, using different experimental conditions, we were able to visualize the intact capsid interacting with NPC cytoplasmic filaments, as an initial docking site, and midway through the NPC. Our data suggests the NPC central channel undergoes large-scale rearrangements to allow translocation of the intact 250-nm long baculovirus capsid. We discuss our results in the light of the hypothetical models of NPC function.
杆状病毒是在宿主细胞核内复制的最大病毒之一。在感染过程中，包含 DNA 病毒基因组的衣壳被释放到细胞质中，并通过一种很大程度上未知的机制将基因组输送到细胞核中。在这里，我们使用杆状病毒 Autographa californica 多角体病毒的衣壳，结合电子显微镜，发现这种衣壳穿过 NPC 并完整地进入细胞核，在那里释放其基因组。为了更好地说明这种衣壳以其天然构象穿过 NPC 的存在，我们使用电子断层摄影术重建了核输入事件。此外，使用不同的实验条件，我们能够可视化完整的衣壳与 NPC 细胞质丝相互作用，作为初始对接位点，并在 NPC 中途。我们的数据表明，NPC 中央通道经历了大规模的重排，以允许完整的 250nm 长杆状病毒衣壳的易位。我们根据 NPC 功能的假设模型讨论了我们的结果。
