title: Polycomb repressive complex 2 targets murine cytomegalovirus chromatin for modification and associates with viral replication centers.
abstract: Regulation of viral transcription by chromatin structure has emerged as a fundamental determinant in the establishment of lytic and latent herpesvirus infections. The Polycomb group (PcG) of epigenetic repressors promotes heterochromatin formation by trimethylating histone H3 on lysine-27 (H3K27me3) and regulates development, stem cell renewal and differentiation and the cell cycle. These cellular processes are tightly coupled to the molecular switch between lytic and latent herpesvirus infections. Using chromatin immunoprecipitation analysis, we observed enrichment of H3K27me3 at the major immediate-early (MIE) locus of murine cytomegalovirus (MCMV) very early following infection of permissive fibroblasts. As lytic replication progressed, we observed a loss of H3K27me3 enrichment concomitant with the appearance of H3K4me3. However, late during infection, as viral replication centers are established, we observed a significant increase in PcG protein association with chromatin. Additionally, in co-immunofluorescence assays using confocal microscopy, we detected strong enrichments for PcG protein within the viral replication compartment, suggesting an association between viral DNA synthesis machinery and PcG proteins. Together, our results suggest a novel, dynamic interaction between PcG epigenetic repressors and MCMV genomes.
authors.affiliation: Department of Microbiology, University of Colorado School of Medicine, Aurora, Colorado, United States of America.
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Abraham
authors.forename: Caroline A
authors.initials: CA
authors.lastname: Kulesza
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000166:cytology; D000071221:Enhancer of Zeste Homolog 2 Protein; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism / Q000821:virology; D005455:Fluorescent Antibody Technique; D011495:Histone-Lysine N-Methyltransferase / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D054884:Host-Pathogen Interactions; D008239:Lysine / Q000378:metabolism; D008745:Methylation; D018146:Muromegalovirus / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D063151:Polycomb Repressive Complex 2; D063146:Polycomb-Group Proteins; D011485:Protein Binding; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014779:Virus Replication
chemical_list: D002843:Chromatin; C107275:Eed protein, mouse; D006657:Histones; D063146:Polycomb-Group Proteins; D012097:Repressor Proteins; C494163:Suz12 protein, mouse; D000071221:Enhancer of Zeste Homolog 2 Protein; C498410:Ezh2 protein, mouse; D011495:Histone-Lysine N-Methyltransferase; D063151:Polycomb Repressive Complex 2; D008239:Lysine