Morey A L, Ferguson D J, Fleming K A
Nuffield Department of Pathology and Bacteriology, University of Oxford, John Radcliffe Hospital, UK.
Histochem J. 1995 Jan;27(1):46-53. doi: 10.1007/BF00164171.
Parvovirus B19 is a single-stranded DNA virus with a specific tropism for human erythroid precursor cells. The virus codes for two overlapping structural (capsid) proteins and one non-structural protein which is thought to perform essential functions in viral replication, transcription and packaging. The ultrastructural localization of these proteins was achieved in cultured haemopoietic cells derived from fetal liver which had been infected in vitro and subsequently embedded in LR White acrylic resin. Postembedding immunogold detection of B19 structural and non-structural proteins was combined with localization of viral nucleic acid by in situ hybridization using a digoxigenin-labelled probe and different sized gold labels. The majority of the B19 capsid protein and DNA present in cells harvested 48 hours post-infection co-localized within the centri-nuclear region of erythroid cells demonstrating characteristic chromatin margination. Relatively little DNA hybridization signal was present over paracrystalline inclusions strongly labelled with anti-capsid protein monoclonal antibody R92F6. Viral DNA and capsid protein were co-localized in apparent egress from the nucleus through nuclear pores. B19 non-structural protein was detected in association with both nuclear and cytoplasmic arrays of capsids, supporting the view that this protein plays an important role in viral packaging and remains associated with the complete viral particle until its release from the cell. Co-localization of viral nucleic acid and proteins at the ultrastructural level is a flexible, rapid and highly specific tool for examination of viral life-cycles within cells.
细小病毒B19是一种单链DNA病毒，对人类红系前体细胞具有特异性嗜性。该病毒编码两种重叠的结构（衣壳）蛋白和一种非结构蛋白，后者被认为在病毒复制、转录和包装过程中发挥重要作用。这些蛋白的超微结构定位是在体外感染后从胎肝中分离培养的造血细胞中实现的，随后将这些细胞包埋在LR White丙烯酸树脂中。通过使用地高辛标记探针和不同大小的金标进行原位杂交来定位病毒核酸，将其与B19结构蛋白和非结构蛋白的包埋后免疫金检测相结合。感染后48小时收获的细胞中，大多数B19衣壳蛋白和DNA共定位于红系细胞的核周区域，呈现出特征性的染色质边缘化现象。在用抗衣壳蛋白单克隆抗体R92F6强烈标记的副结晶包涵体上，DNA杂交信号相对较少。病毒DNA和衣壳蛋白在通过核孔从细胞核明显逸出的过程中共定位。检测到B19非结构蛋白与核内和胞质内的衣壳阵列相关，这支持了该蛋白在病毒包装中起重要作用并在病毒颗粒从细胞释放之前一直与其相关的观点。在超微结构水平上病毒核酸和蛋白的共定位是研究细胞内病毒生命周期的一种灵活、快速且高度特异的工具。
