Architecture and biogenesis of plus-strand RNA virus replication factories

Plus-strand RNA virus replication occurs in tight association with cytoplasmic host cell membranes. Both, viral and cellular factors cooperatively generate distinct organelle-like structures, designated viral replication factories. This compartmentalization allows coordination of the different steps of the viral replication cycle, highly efficient genome replication and protection of the viral RNA from cellular defense mechanisms. Electron tomography studies conducted during the last couple of years revealed the three dimensional structure of numerous plus-strand RNA virus replication compartments and highlight morphological analogies between different virus families. Based on the morphology of virusinduced membrane rearrangements, we propose two separate subclasses: the invaginated vesicle/spherule type and the double membrane vesicle type. This review discusses common themes and distinct differences in the architecture of plus-strand RNA virus-induced membrane alterations and summarizes recent progress that has been made in understanding the complex interplay between viral and co-opted cellular factors in biogenesis and maintenance of plus-strand RNA virus replication factories.

A cellular protein specifically binds to the 3' -terminal sequences of hepatitis C virus intermediate negative-strand RNA

Objective To study the mechanism of the cellular proteins involved in the process of replication of hepatitis C virus (HCV) negative-strand RNA.Methods Ultraviolet (UV) cross-linking was used to identify the cellular proteins that would bind to the 3' -end of HCV negative-strand RNA. Competition experiment was used to confirm the specificity of this binding, in which excess nonhomologous protein and RNA transcripts were used as competitors. The required binding sequence was determined by mapping, then the binding site was predicted through secondary structure analysis.Results A cellular protein of 45 kD (p45) was found to bind specifically to the 3' -end of HCV negative-strand RNA by UV cross-linking, nhomologous proteins and RNA transcripts could not compete out this binding, whereas the unlabeled 3' -end of HCV negative-strand RNA could. Mapping of the protein-binding site suggested that the 3' -end 131-278nt of HCV negative-strand RNA was the possible protein-binding region. Analysis of RNA secondary structure presumed that the potential binding site was located at 194-GAAAGAAC-201.Conclusion The cellular protein p45 could specifically bind to the secondary structure of the 3' -end of HCV intermediate negative-strand RNA, and may play an important role in HCV RNA replication.

形成丙型肝炎病毒负链复制体的相关蛋白的分析

【目的】确定丙型肝炎病毒 (HCV)非结构蛋白NS5B以及肝母细胞瘤株HepG2胞浆提取物中的宿主蛋白与HCV负链RNA 3′末端的特异性结合作用。【方法】用蛋白 核酸紫外交联试验分别检测NS5B以及HepG2胞浆提取物中的宿主蛋白与HCV负链RNA 3′末端的结合作用 ,用非同源RNA和非同源蛋白作为竞争物分析这种结合的特异性。【结果】NS5B以及宿主细胞内一约 4 5ku的蛋白质 (简称P4 5 )均可与HCV负链RNA 3′末端特异性结合。【结论】NS5B和P4 5是HCV负链RNA

丙型肝炎病毒NS3-5B转基因小鼠模型的构建

目的:构建表达丙型肝炎病毒(HCV)NS3-5B蛋白的转基因小鼠模型。方法:显微注射线性化p IRES2-EGFP-NS3-5B载体到小鼠受精卵,制备并传代筛选HCV NS3-5B转基因小鼠;通过血清谷丙转氨酶(ALT)、谷草转氨酶(AST)检测和肝脏HE染色,对6周龄转基因小鼠进行肝功能评价。结果:PCR、RT-PCR和Western印迹结果表明HCV NS3-5B转基因小鼠构建成功;6周龄部分转基因小鼠血清ALT和AST值升高,但差别无统计学意义,肝组织形态无改变。结论:构建了HCV NS3-5B转基因小鼠模型,为进一步在体研究HCV复制复合体建立了平台。