Cytomegalovirus UL91 Is Essential for Transcription of Viral True Late (?2) Genes

• Type of Material: Article
• Authors: Shinya Omoto, Emory University; Edward S Mocarski, Emory University
• Language: English
• Date: 2013-08
• Publisher: American Society for Microbiology
• Publication Version: Final Published Version
• Copyright Statement: © 2013, American Society for Microbiology. All Rights Reserved.
• Final Published Version (URL): http://jvi.asm.org/content/87/15/8651
• Title of Journal or Parent Work: Journal of Virology
• ISSN: 0022-538X
• Volume: 87
• Issue: 15
• Start Page: 8651
• End Page: 8664
• Grant/Funding Information: Public Health Service grant RO1 AI020211 funded this research.
• Research Categories: Health Sciences, Immunology

Abstract

Human cytomegalovirus-encoded UL91 is a betagamma gene that is essential for viral replication. Here we show that the 111-amino-acid (aa) UL91 protein controls accumulation of true-late (γ2) viral transcripts. The primate betaherpesvirus conserved N-terminal region from aa 1 to 71 is sufficient to fully reconstitute function. Evaluation of viral DNA, RNA, and antigen revealed that UL91 protein is expressed with leaky-late (γ1) kinetics, localizes in the nucleus without influencing viral DNA synthesis, and must be present from 48 h postinfection to support full expression of late viral transcripts and proteins. In the absence of UL91, viral capsid assembly in the nucleus of infected cells is significantly reduced, and mature, cytoplasmic virions fail to form. Taken together, the evidence shows that UL91 regulates late viral gene expression by a mechanism that is apparently conserved in betaherpesviruses and gammaherpesviruses.