Robertson A T, Caughman G B, Gray W L, Baumann R P, Staczek J, O'Callaghan D J
Department of Microbiology and Immunology, Louisiana State University Medical Center, Shreveport 71130-3932.
Virology. 1988 Oct;166(2):451-62. doi: 10.1016/0042-6822(88)90516-8.
Equine herpesvirus type 1 (EHV-1) gene expression is coordinately regulated in an alpha, beta, gamma fashion. Viral alpha gene products include a 6.0-kb immediate early (IE) mRNA species (W. L. Gray et al., 1987, Virology 158, 79-87) and at least four closely related IE polypeptides (IEPs) (G.B. Caughman et al., 1985, Virology 145, 49-61). In this report, we describe results obtained from a series of in vitro translation experiments which were performed in an effort to characterize the IEPs and identify the mechanism by which individual IE protein species are generated. Our data indicate that a family of IEPs is generated in vitro from the 6.0-kb mRNA size class and that these IEPs correspond in overall size and antigenicity to those synthesized in infected cells. Using time-course/pulse-chase analyses, we show that production of three of the major IEPs [IE1' (193 kDa), IE3' (166 kDa), and IE4' (130 kDA)] occurs concomitantly, that none of these protein species can be chased completely into another, and that at least two additional minor species appear to be processed following synthesis. Finally, we show that the 6.0-kb mRNA species isolated during early or late stages of the infection cycle can be translated to yield all of the major IE proteins, indicating that production of the family of IEPs is not dependent upon accumulation of the IE mRNA which occurs during a cycloheximide blocked infection cycle. The implications of these findings are discussed as they relate to the origin and production of the IEPs both in vivo and in vitro.
1型马疱疹病毒（EHV-1）的基因表达以α、β、γ方式协同调控。病毒α基因产物包括一种6.0 kb的立即早期（IE）mRNA种类（W. L. Gray等人，1987年，《病毒学》158卷，79 - 87页）以及至少四种密切相关的立即早期多肽（IEP）（G.B. Caughman等人，1985年，《病毒学》145卷，49 - 61页）。在本报告中，我们描述了一系列体外翻译实验的结果，这些实验旨在对IEP进行表征，并确定产生单个IE蛋白种类的机制。我们的数据表明，在体外从6.0 kb mRNA大小类别中产生了一族IEP，并且这些IEP在总体大小和抗原性上与在感染细胞中合成的IEP相对应。使用时间进程/脉冲追踪分析，我们表明三种主要的IEP [IE1'（193 kDa）、IE3'（166 kDa）和IE4'（130 kDa）]的产生是同时发生的，这些蛋白种类中没有一种可以完全转变为另一种，并且至少有另外两种较小的种类似乎在合成后会被加工。最后，我们表明在感染周期早期或晚期分离的6.0 kb mRNA种类可以被翻译产生所有主要的IE蛋白，这表明IEP家族的产生不依赖于在放线菌酮阻断的感染周期中发生的IE mRNA的积累。讨论了这些发现与体内和体外IEP的起源及产生的关系。
