Critical Role for the Human Cytomegalovirus Major Immediate Early Proteins in Recruitment of RNA Polymerase II and H3K27Ac To an Enhancer-Like Element in OriLyt. Microbiol Spectr 2023 Feb 14;11(1):e0314422
Date
01/17/2023Pubmed ID
36645269Pubmed Central ID
PMC9927211DOI
10.1128/spectrum.03144-22Scopus ID
2-s2.0-85148092420 (requires institutional sign-in at Scopus site)Abstract
Human cytomegalovirus (HCMV) is an opportunistic pathogen that infects most of the population. The complex 236 kbp genome encodes more than 170 open reading frames, whose expression is temporally regulated by both viral transcriptional regulators and cellular factors that control chromatin and transcription. Here, we have used state of the art genomic technologies to investigate the viral transcriptome in conjunction with 2 key transcriptional regulators: Pol II and H3K27Ac. Although it is well known that the major immediate early (IE) proteins activate early gene expression through both direct and indirect interactions, and that histone modifications play an important role in regulating viral gene expression, the role of the IE proteins in modulating viral chromatin is not fully understood. To address this question, we have used a virus engineered for conditional expression of the IE proteins combined with RNA and Chromatin immunoprecipitation (ChIP) analyses to assess the role of these proteins in modulating both viral chromatin and gene expression. Our results show that (i) there is an enhancer-like element in OriLyt that is extraordinarily enriched in H3K27Ac; (ii) in addition to activation of viral gene expression, the IE proteins play a critical role in recruitment of Pol II and H3K27Ac to this element. IMPORTANCE HCMV is an important human pathogen associated with complications in transplant patients and birth defects. The complex program of viral gene expression is regulated by both viral proteins and host factors. Here, we have investigated the role of the immediate early proteins in regulating the viral epigenome. Our results show that the viral immediate early proteins bring about an enormous enrichment of H3K27Ac marks at the OriLyt RNA4.9 promoter, concomitant with an increase in RNA4.9 expression. This epigenetic characteristic adds importantly to the view that OriLyt has structural and functional characteristics of a strong enhancer that, we now discover, is regulated by IE proteins.
Author List
Forte E, Li M, Ayaloglu Butun F, Hu Q, Borst EM, Schipma MJ, Piunti A, Shilatifard A, Terhune SS, Abecassis M, Meier JL, Hummel MAuthor
Scott Terhune PhD Professor in the Microbiology and Immunology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
ChromatinCytomegalovirus
Gene Expression Regulation, Viral
Humans
Immediate-Early Proteins
RNA Polymerase II
Viral Proteins
