Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA.
Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida, USA.
J Virol. 2018 May 14;92(11). doi: 10.1128/JVI.00173-18. Print 2018 Jun 1.
Herpes simplex virus 1 (HSV-1) establishes a lifelong latent infection in host peripheral neurons, including the neurons of the trigeminal ganglia (TG). HSV-1 can reactivate from neurons to cause recurrent infection. During latency, the insulator protein CTCF occupies DNA binding sites on the HSV-1 genome, and these sites have been previously characterized as functional enhancer-blocking insulators. Previously, CTCF was found to be dissociated from wild-type virus postreactivation but not in mutants that do not reactivate, indicating that CTCF eviction may also be an important component of reactivation. To further elucidate the role of CTCF in reactivation of HSV-1, we used recombinant adeno-associated virus (rAAV) vectors to deliver a small interfering RNA targeting CTCF to peripheral neurons latent with HSV-1 in rabbit TG. Our data show that CTCF depletion resulted in long-term and persistent shedding of infectious virus in the cornea and increased ICP0 expression in the ganglia, indicating that CTCF depletion facilitates HSV-1 reactivation. Increasing evidence has shown that the insulator protein CTCF regulates gene expression of DNA viruses, including the gammaherpesviruses. While CTCF occupation and insulator function control gene expression in DNA viruses, CTCF eviction has been correlated to increased lytic gene expression and the dissolution of transcriptional domains. Our previous data have shown that in the alphaherpesvirus HSV-1, CTCF was found to be dissociated from the HSV-1 genome postreactivation, further indicating a global role for CTCF eviction in the transition from latency to reactivation in HSV-1 genomes. Using an rAAV8, we targeted HSV-1-infected peripheral neurons for CTCF depletion to show that CTCF depletion precedes the shedding of infectious virus and increased lytic gene expression , providing the first evidence that CTCF depletion facilitates HSV-1 reactivation.
单纯疱疹病毒 1（HSV-1）在宿主外周神经元中建立终身潜伏感染，包括三叉神经节（TG）的神经元。HSV-1 可以从神经元中重新激活，导致复发性感染。在潜伏期间，绝缘子蛋白 CTCF 占据 HSV-1 基因组上的 DNA 结合位点，这些位点以前被表征为功能性增强子阻断绝缘子。先前发现，在再激活后的野生型病毒中，CTCF 与病毒分离，但在不重新激活的突变体中则没有，这表明 CTCF 逐出也可能是再激活的一个重要组成部分。为了进一步阐明 CTCF 在 HSV-1 再激活中的作用，我们使用重组腺相关病毒（rAAV）载体将靶向 CTCF 的小干扰 RNA 递送到兔 TG 中潜伏的 HSV-1 外周神经元。我们的数据表明，CTCF 耗竭导致角膜中传染性病毒的长期和持续释放，并增加了神经节中的 ICP0 表达，表明 CTCF 耗竭促进了 HSV-1 的再激活。越来越多的证据表明，绝缘子蛋白 CTCF 调节包括γ疱疹病毒在内的 DNA 病毒的基因表达。虽然 CTCF 占据和绝缘子功能控制 DNA 病毒中的基因表达，但 CTCF 逐出已与裂解基因表达的增加和转录域的溶解相关。我们之前的数据表明，在α疱疹病毒 HSV-1 中，发现 CTCF 在再激活后与 HSV-1 基因组分离，这进一步表明 CTCF 逐出在 HSV-1 基因组从潜伏到再激活的转变中具有全局作用。我们使用 rAAV8 靶向 HSV-1 感染的外周神经元进行 CTCF 耗竭，以表明 CTCF 耗竭先于传染性病毒的释放和裂解基因表达的增加，这首次提供了 CTCF 耗竭促进 HSV-1 再激活的证据。
