Papanikolaou Eleni, Kouvatsis Vlassis, Dimitriadis Georgios, Inoue Naoki, Arsenakis Minas
Laboratory of General Microbiology, Section of Genetics, Developmental and Molecular Biology, School of Biology, Aristotle Universit, Thessaloniki 54006, Greece.
Virus Res. 2002 Oct;89(1):89-101. doi: 10.1016/s0168-1702(02)00126-0.
The human herpesvirus 6 (HHV-6) immediate early-A locus (IE-A) locates in the position analogous to the human cytomegalovirus (HCMV) major IE (MIE) locus that is well-known to play critical roles in viral infection. Similarly to HCMV MIE, HHV-6 IE-A consists of two genetic units, IE1 and IE2, corresponding to open reading frames U90-U89 and U90-U86/87, respectively. However, the HHV-6 IE-A locus exhibits limited sequence homology with the HCMV MIE locus. In this study, to characterize HHV-6 IE2 gene products, polyclonal antibodies against four domains of the U86/87 open reading frame were generated by immunization of rabbits with bacterially-expressed proteins. Three polypeptides derived from the U86/87 region with apparent molecular masses of 100, 85 and 55 kD were detected in HHV-6-infected cells 3 days after infection, while IE1 polypeptides with apparent molecular mass greater than 170 kD were detectable as early as 8 h. Mapping of the IE2 gene products with the antibodies suggests differential splicing and alternative translation initiation in the IE2 genetic unit. The IE2 products show a mixed cytoplasmic and nuclear localization pattern. In addition, the 437 amino acid carboxyl-terminus domain bound to a DNA fragment containing the putative IE-A promoter. These results suggest that HHV-6 IE2 plays a critical role in transcriptional regulation and viral growth as does HCMV IE2, although it is likely that HHV-6 IE2 has expression kinetics different from HCMV IE2.
人类疱疹病毒6型（HHV-6）即刻早期A基因座（IE-A）位于与人类巨细胞病毒（HCMV）主要即刻早期（MIE）基因座类似的位置，众所周知，该基因座在病毒感染中起关键作用。与HCMV MIE类似，HHV-6 IE-A由两个遗传单位IE1和IE2组成，分别对应于开放阅读框U90-U89和U90-U86/87。然而，HHV-6 IE-A基因座与HCMV MIE基因座的序列同源性有限。在本研究中，为了表征HHV-6 IE2基因产物，通过用细菌表达的蛋白免疫兔子，产生了针对U86/87开放阅读框四个结构域的多克隆抗体。感染后3天，在HHV-6感染的细胞中检测到来自U86/87区域的三种多肽，其表观分子量分别为100、85和55 kD，而表观分子量大于170 kD的IE1多肽早在8小时就可检测到。用抗体对IE2基因产物进行定位表明，IE2遗传单位存在差异剪接和可变翻译起始。IE2产物表现出细胞质和细胞核混合定位模式。此外，437个氨基酸的羧基末端结构域与一个含有推定IE-A启动子的DNA片段结合。这些结果表明，HHV-6 IE2与HCMV IE2一样，在转录调控和病毒生长中起关键作用，尽管HHV-6 IE2的表达动力学可能与HCMV IE2不同。
