de Bruyn Kops A, Uprichard S L, Chen M, Knipe D M
Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
Virology. 1998 Dec 5;252(1):162-78. doi: 10.1006/viro.1998.9450.
Herpesviral transcription, DNA synthesis, and capsid assembly occur within the infected cell nucleus. To further define the spatial relationship among these processes, we have examined the intranuclear distributions of viral DNA replication, gene regulatory, and capsid proteins using dual label immunofluorescence and confocal microscopy. We observed that several of the viral DNA replication proteins localize preferentially to punctate structures within replication compartments while the major transcriptional activator, ICP4, and the ICP27 regulatory protein show a more diffuse distribution within replication compartments. The viral proteins that show a punctate distribution in replication compartments redistribute from these compartments to prereplicative sites when viral DNA replication is inhibited, whereas viral proteins that show a diffuse distribution remain within replication compartments when viral DNA replication is inhibited. Thus the sites of viral DNA replication and late transcription appear to be distinct but codistribute within the boundaries of replication compartments. The major capsid protein, ICP5, also localizes initially to a diffuse distribution within replication compartments, but during the time of maximal progeny virus assembly, ICP5 becomes localized to punctate structures within replication compartments that are often near the punctate structures occupied by viral DNA replication proteins. Hence the processes of viral DNA replication, late transcription, and capsid assembly show a general overlapping distribution within replication compartments but appear to be located at distinct sites within these regions of the infected cell nucleus.
疱疹病毒转录、DNA合成和衣壳组装均在受感染的细胞核内发生。为了进一步明确这些过程之间的空间关系，我们利用双标记免疫荧光和共聚焦显微镜检查了病毒DNA复制、基因调控和衣壳蛋白在核内的分布。我们观察到，几种病毒DNA复制蛋白优先定位于复制区室内的点状结构，而主要转录激活因子ICP4和ICP27调控蛋白在复制区室内分布更为弥散。当病毒DNA复制受到抑制时，在复制区室内呈点状分布的病毒蛋白会从这些区域重新分布到复制前位点，而呈弥散分布的病毒蛋白在病毒DNA复制受抑制时仍留在复制区室内。因此，病毒DNA复制和晚期转录位点似乎是不同的，但在复制区室边界内共分布。主要衣壳蛋白ICP5最初也定位于复制区室内的弥散分布，但在子代病毒组装达到最大值时，ICP5定位于复制区室内的点状结构，这些结构通常靠近被病毒DNA复制蛋白占据的点状结构。因此，病毒DNA复制、晚期转录和衣壳组装过程在复制区室内呈现出总体重叠分布，但似乎位于受感染细胞核这些区域内的不同位点。
