ROLE OF THE LAT-ICP0 LOCUS IN REGULATING HSV LATENCY

描述(由申请人提供)：单纯疱疹病毒(HSV)反复感染是一个重要的临床问题。了解复发性疱疹的本质的基础是准确地确定HSV如何在其双重生命周期的两个阶段之间交替，即潜伏期和生产性感染的重新激活。LAT-ICP0基因座在HSV-1潜伏期和重新激活的调节中起着核心作用。编码潜伏期相关转录本(LAT)和感染细胞多肽0(ICP0)的基因在HSV基因组的重复区域形成一个连续的位点。明确地说，LAT和ICP0基因位于单纯疱疹病毒1型S双链基因组的相反链上，并且有显著的重叠。因此，丰富的LAT可以与ICP0 mRNA中0.75kb的互补序列杂交。虽然LAT-ICP0基因座的反义排列早已被认识到，但LAT RNAs作为ICP0基因表达的“反义抑制物”的假说还没有得到严格的分析。LAT和ICP0基因的并列反映了它们在潜伏期中的相反作用。虽然LAT RNA有助于维持HSV潜伏期，但ICP0的表达是诱导HSV-1重新激活的必要条件和充分条件。相反，不表达ICP0非常有利于HSV基因组进入转录抑制状态。因此，反义抑制ICP0 mRNA的翻译是LAT促进潜伏期维持的一种机制。这项研究计划的目的是评估LAT RNAs和ICP0形成一对相互依赖的、相反的调节因子的概念，这些调节因子是HSV潜伏期的阴阳。具体地说，将获得遗传证据来检验这样的假设：在三叉神经节细胞培养模型中，所有诱导HSV-1重新激活的病毒蛋白都通过(A)诱导ICP0，(B)抑制LAT转录，或(C)两者兼而有之而实现这种表型。

DESCRIPTION (provided by applicant): Recurrent infections with herpes simplex viruses (HSV) are a significant clinical problem. Fundamental to understanding the nature of recurrent herpetic disease is determining precisely how HSV alternates between the two phases of its dual life cycle, latency and reactivation of productive infection. The LAT-ICP0 locus plays a central role in the regulation of HSV-1 latency and reactivation. The genes that encode for the latency-associated transcripts (LATs) and infected cell polypeptide 0 (ICP0) form a continuous locus in the repeated regions of the HSV genome. Specifically, the LAT and ICP0 genes lie on opposite strands of HSV-1's double-stranded DNA genome and share a significant overlap. Thus, the abundant LATs can hybridize to 0.75 kilobases of complementary sequence in ICP0 mRNA. While the antisense arrangement of the LAT-ICP0 locus has long been recognized, the hypothesis that LAT RNAs serve as "antisense repressors" of ICP0 gene expression has not been rigorously analyzed. The juxtaposition of the LAT and ICP0 genes mirrors their opposing roles in latency. While LAT RNAs facilitate the maintenance of HSV latency, expression of ICP0 is necessary and sufficient to induce HSV-1 reactivation. Conversely, failure to express ICP0 is highly conducive to HSV genomes entering a transcriptionally repressed state. Thus, antisense repression of ICP0 mRNA translation is one mechanism by which LATs may facilitate the maintenance of latency. The goal of this research proposal is to evaluate the concept that LAT RNAs and ICP0 form a pair of mutually dependent, opposite regulators that are the yin and yang of HSV latency. Specifically, genetic evidence will be obtained to test the hypothesis that "All viral proteins that induce HSV-1 reactivation in the trigeminal ganglion cell culture model achieve this phenotype via (a) induction of ICP0, (b) suppression of LAT transcription, or (c) both."