Our long-term goal is to determine how cellular transcription factors interface with the HSV-1 genome toachieve latent infections and to reactivate the genome. Eukaryotic genomes are regulated via post-translational modifications and alterations to histones and higher order chromatin structures. Because HSV-1replicates in a eukaryotic milieu, the virus is subject to chromatin-mediated effects. Our previous workdemonstrated that nucleosomes are present and activation-linked histone modifications are induced on theHSV-1 genome during acute infections. The objective of the current proposal is to investigate the role ofchromatin in regulation of HSV-1 acute infection, latency, and reactivation. We will explore how dynamicchanges between euchromatin and herochromatin regulate HSV-1. Our specific goals are to determinewhether specific cellular histone modification enzymes, histone variants, and ATP-dependent remodelingcomplexes promote acute HSV-1 infection and reactivation, and whether cellular heterochromaticmechanisms repress the genome during latency. We will also investigate the presence of possiblechromatin-based insulators to buffer the expressed LAT region during latency, to prevent enchroachment ofsurrounding heterochromatin. The work will interface with each of the additional Projects in the Programthrough (1) mapping of histone modifications on HSV-1 microarrays (with Project 1), (2) identification ofchromatin boundaries (with Project 2), examining the role of histone modifications in HSV^-1 regulation in thePC12 in vitro system (with Project 4). Our studies will provide the first comprehensive analysis of chromatinin stages of the HSV-1 viral life cycle. It is noteworthy that chromatin regulation has become a focus ofstrategies for intervention in human diseases. The research proposed here will reveal criticai Chromatisimodulating enzymes for HSV-1 latency and reactivation and in this way will provide new interventionpossibilities.
