Johnson Reed F, McCarthy Sarah E, Godlewski Peter J, Harty Ronald N
Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce St., Philadelphia, PA 19104, USA.
J Virol. 2006 Jun;80(11):5135-44. doi: 10.1128/JVI.01857-05.
The packaging of viral genomic RNA into nucleocapsids and subsequently into virions is not completely understood. Phosphoprotein (P) and nucleoprotein (NP) interactions link NP-RNA complexes with P-L (polymerase) complexes to form viral nucleocapsids. The nucleocapsid then interacts with the viral matrix protein, leading to specific packaging of the nucleocapsid into the virion. A mammalian two-hybrid assay and confocal microscopy were used to demonstrate that Ebola virus VP35 and VP40 interact and colocalize in transfected cells. VP35 was packaged into budding virus-like particles (VLPs) as observed by protease protection assays. Moreover, VP40 and VP35 were sufficient for packaging an Ebola virus minigenome RNA into VLPs. Results from immunoprecipitation-reverse transcriptase PCR experiments suggest that VP35 confers specificity of the nucleocapsid for viral genomic RNA by direct VP35-RNA interactions.
病毒基因组RNA包装进核衣壳以及随后包装进病毒粒子的过程尚未完全明确。磷蛋白（P）与核蛋白（NP）的相互作用将NP-RNA复合物与P-L（聚合酶）复合物相连，以形成病毒核衣壳。然后，核衣壳与病毒基质蛋白相互作用，导致核衣壳特异性地包装进病毒粒子。利用哺乳动物双杂交试验和共聚焦显微镜证明，埃博拉病毒VP35和VP40在转染细胞中相互作用并共定位。通过蛋白酶保护试验观察到，VP35被包装进出芽的病毒样颗粒（VLP）中。此外，VP40和VP35足以将埃博拉病毒微型基因组RNA包装进VLP。免疫沉淀-逆转录酶PCR实验结果表明，VP35通过VP35与RNA的直接相互作用赋予核衣壳对病毒基因组RNA的特异性。
