Chromatin and Herpes Simplex Virus Latency

描述(申请人提供)：单纯疱疹病毒导致相当大的发病率和死亡率。它们在粘膜部位经历裂解的、有效的感染，并扩散到感觉神经节，在那里它们在宿主的一生中经历潜伏的感染。重新激活会导致反复感染和疾病。抗病毒药物已经被定义为抑制裂解感染周期，但还没有针对潜伏病毒的方法。我们已经确定了病毒基因产物如LAT和ICP0在裂解和潜伏感染过程中调节染色质结构的作用，但需要进一步的基本信息来发现针对HSV潜伏感染的治疗方法。在这一应用中，我们的具体目标是：a.检验假设，在急性感染和三叉神经节潜伏感染期间，HSV潜伏期相关转录本通过其可能的机制降低裂解基因的表达：a.在不同的HSV-1毒株中，Lat突变产生不同的表型。B.Lat作为一种长的非编码RNA，将组蛋白修饰复合体招募到病毒基因组中。C.Lat通过作为miRNA的前体导致染色质的变化，通过对miRNA突变病毒的研究，降低ICP0的表达。D.后期转录，而不是顺式作用的调控DNA序列，促进病毒裂解基因上的染色质。2.明确HSV ICP0蛋白在三叉神经节急性感染和潜伏感染过程中对染色质结构的调控机制。我们有令人兴奋的未发表的结果，ICP0突变病毒在潜伏感染期间在其基因组上有不同的染色质图谱。我们将测试ICP0通过将组蛋白修饰酶招募到病毒和细胞基因来改变染色质状态的假设。3.明确LAT和ICP0在HSV染色质调控中的相互作用。我们将通过突变ICP0启动子或突变ICP0翻译起始点，并通过构建LAT和ICP0双突变病毒来测试LAT与ICP0转录本形成双链RNA以招募组蛋白修饰酶的假设，以确定它们对潜伏感染和病毒染色质的组合作用。 公共卫生相关性：单纯疱疹病毒导致相当大的生殖器、眼部和神经系统疾病，生殖器疱疹增加了艾滋病毒感染的风险。有针对单纯疱疹病毒活跃生长的药物，但没有针对潜伏感染的药物。这项研究将确定单纯疱疹病毒潜伏感染的基本机制，并为潜在的药物治疗这些病毒的潜伏感染寻找新的靶点。

DESCRIPTION (provided by applicant): Herpes simplex viruses cause considerable morbidity and mortality. They undergo a lytic, productive infection at the mucosal sites and spread into sensory ganglia, where they undergo a latent infection for the life of the host. Reactivation leads to recurrent infection and disease. Antiviral drugs have been defined that inhibit the lytic infection cycle, but there are no approaches that target the latent virus. We hav defined the role of viral gene products such as LAT and ICP0 in modulating the chromatin structure during lytic and latent infection, but further basic information is needed about these mechanisms for discovery of therapeutics that target HSV latent infection. In this application our specific aims are: a. To test hypotheses for possible mechanisms by which the HSV latency-associated transcript reduces lytic gene expression during acute infection and during latent infection of trigeminal ganglia: a. LAT mutations give different phenotypes in different HSV-1 strains. b. LAT acts as a long noncoding RNA that recruits histone-modifying complexes to the viral genome. c. LAT leads to chromatin changes by serving as a precursor to an miRNA that reduces ICP0 expression through studies of miRNA mutant viruses. d. LAT transcription, rather than cis-acting regulatory DNA sequences, promotes chromatin on the viral lytic genes. 2. To define the mechanisms by which the HSV ICP0 protein regulates chromatin structure during acute infection and latent infection of trigeminal ganglia. We have exciting unpublished results that ICP0 mutant viruses have a different chromatin profile on their genome during latent infection. We will test the hypothesis that ICP0 acts to alter the chromatin state by recruiting histone modification enzymes to viral and cellular genes. 3. To define Interactions between LAT and ICP0 in regulating HSV chromatin. We will test the hypothesis that LAT forms duplex RNA with ICP0 transcripts to recruit histone modifying enzymes by mutating the ICP0 promoter or mutating the ICP0 translational initiation site and by constructing LAT and ICP0 double mutant viruses to determine their combinatorial effects on latent infection, and viral chromatin. PUBLIC HEALTH RELEVANCE: Herpes simplex viruses cause considerable genital, ocular and nervous system disease, and genital herpes increases the risk of HIV infection. There are drugs that target the active growth of herpes simplex virus but none that target the latent infection. This research will define basic mechanisms of herpes simplex virus latent infection and new targets for potential drugs to treat the latent infection of these viruses