Characterization of gammaherpesvirus 68 gene 50 transcription
Characterization of gammaherpesvirus 68 gene 50 transcription
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DOI：
10.1128/jvi.74.4.2029-2037.2000
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发表时间：
2000-02-01
影响因子：
5.4
通讯作者：
Speck, SH
中科院分区：
文献类型：
--
作者：
Liu, SF;Pavlova, IV;Speck, SH
基因 50 是唯一在特征性的伽马疱疹病毒中保守的立即早期基因。最近已经证明，对于人类病毒EB病毒（EBV）和卡波西肉瘤相关疱疹病毒（KSHV），基因50编码产物在一些潜伏感染细胞系中的异位表达可以导致病毒复制的诱导，表明基因50很可能在调节伽马疱疹病毒重新激活中发挥关键作用。在这里，我们证明鼠伽马疱疹病毒 68 (伽马 HV68) 基因 50 是一种立即早期基因，并且伽马 HV68 基因 50 的转录导致基因 50 转录物的剪接和未剪接形式的产生。转录物在 5' 端附近的剪接用于延伸基因 50 开放阅读框，正如对于由 KSHV 和疱疹病毒 saimiri 编码的基因 50 转录物所观察到的那样（Whitehouse 等人，J. Virol. 71:2550-2554, 1997 ；Lukac 等人，Virology 252:304-312, 1998 ；Sun 等人，Proc.国家科学。美国 95：10866-10871，1998）。逆转录 PCR 分析与 S1 核酸酶保护测定相结合，提供了证据表明基因 50 转录起始于 γ HV68 基因组中 bp 66468 至 66502 区域内的多个位点。推定基因 50 转录起始位点上游区域的功能表征证明了方向依赖性启动子活性，并鉴定了编码推定基因 50 启动子的 110 bp 区域（bp 66442 至 66552）。最后，我们证明γ HV68：基因50可以反式激活γ HV68基因57启动子，这是其他γ疱疹病毒中基因50编码的反式激活子的已知早期基因靶标。这些研究表明，γ HV68 基因 50 与其他γ疱疹病毒中的基因 50 同源物具有几个重要的分子相似性，从而为未来研究分析γ HV68 基因 50 编码蛋白在体内急性病毒复制和潜伏期重新激活中的作用提供了动力。
Gene 50 is the only immediate-early gene that appears to be conserved among the characterized gammaherpesviruses. It has recently been demonstrated for the human viruses Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) that ectopic expression of the gene 50-encoded product in some latently infected cell lines can lead to the induction of virus replication, indicating that gene 50 is likely to play a pivotal role in regulating gammaherpesvirus reactivation. Here we demonstrate that the murine gammaherpesvirus 68 (gamma HV68) gene 50 is an immediate-early gene and that transcription of gamma HV68 gene 50 leads to the production of both spliced and unspliced forms of the gene 50 transcript. Splicing of the transcript near the 5' end serves to extend the gene 50 open reading frame, as has been observed for the gene 50 transcripts encoded by KSHV and herpesvirus saimiri (Whitehouse ct al., J. Virol. 71:2550-2554, 1997; Lukac et al., Virology 252:304-312, 1998; Sun et al., Proc. Natl. Acad. Sci. USA 95:10866-10871, 1998). Reverse transcription-PCR analyses, coupled with S1 nuclease protection assays, provided evidence that gene 50 transcripts initiate at several sites within the region from bp 66468 to 66502 in the gamma HV68 genome. Functional characterization of the region upstream of the putative gene 50 transcription initiation site demonstrated orientation-dependent promoter activity and identified a 110 bp region (bp 66442 to 66552) encoding the putative gene 50 promoter. Finally, we demonstrate that the gamma HV68: gene 50 can transactivate the gamma HV68 gene 57 promoter, a known early gene target of the gene 50-encoded transactivator in other gammaherpesviruses. These studies show that the gamma HV68 gene 50 shares several important molecular similarities with the gene 50 homologs in other gammaherpesviruses and thus provides an impetus for future studies analyzing the role of the gamma HV68 gene 50-encoded protein in acute virus replication and reactivation from latency in vivo.