The infected cell protein No. 0 (ICP0) is a 775 amino acid multifunctional protein that plays a very important role in the human biology of herpes simplex viruses 1 and 2 (HSV-1 and 2). ICP0 is encoded by 3 exons. ICP0 is encoded by 3 exons. The protein has been reported to play a major role in reactivation from latency and in productive infection it is essential for ythe manifestations of pathologies associated with HSV infection. In this application for renewed support we propose to continue the research conducted over the past 4 years. Specifically: (1) Recent studies from this laboratory have shown that HSV-1 ICP0 acts in in vitro assays as an ubiquitin ligase with rather unique properties: thus the ubiquitin- conjugating enzymes (E2) UbcH5a and UbcH6 interact with sequences encoded by exon 2 whereas the UbcH3 (cdc34) interacts with sequences encoded by exon 3. One target of the ubiquitin ligase is cdc34, a ubiquiting conjugating enzyme responsible for the turnover of D cyclins. The objectives of AIM 1 is to investigate the role of ICP0 as a ubiquitin ligase. Specifically, the objectives are to map and characterize the E3 ubiquitin ligase site in exon 3 and to define the cellular proteins that are the targets of this ICP0 ubiquitin ligase. (2) A comparison of wild-type virus with a mutant in which ICP0 has been replaced by a cDNA copy showed that in rabbit skin cells the onset of accumulation of early (?) and later (? and ?) proteins can be delayed by as much as 6 to 8 hrs although ultimately the cells synthesize equal amounts of key proteins and yield equivalent amounts of infectious virus. Yet the data clearly show that HSV-1 DNA has been delivered to the nucleus. The fact that none of the viral genes are expressed until several hours after infection and that the mutation maps to the transcribed domain of ICP0 raises the possibility that ICP0 plays a critical role in the initiation of expression of viral genes in a cell-type dependent manner. The objective of AIM 2 is to investigate the role of ICP0 at very early stages of infection. (3) We and other laboratories has assigned functions to the exon 2 and the carboxyl-terminal half of exon 3. A 200+ amino acid stretch in the amino terminal domain of ICP0 is uncharted and no functions have been ascribed to it. We have made a series of linker insertion mutants and have identified small regions of sequences conserved in HSV-1 and HSV-2. Linker insertions in two of the conserved sequences attenuate the virus. The objective of AIM 3 is to continue the investigation of the functions of the uncharted domains of ICP0. We expect that the proposed studies will help understand the role of ICP0 in the evolution of diseases caused by HSV-1 and HSV-2.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37CA078766-08
Application #
6892175
Study Section
Experimental Virology Study Section (EVR)
Program Officer
Daschner, Phillip J
Project Start
1998-07-29
Project End
2008-04-30
Budget Start
2005-05-01
Budget End
2006-04-30
Support Year
8
Fiscal Year
2005
Total Cost
$381,250
Indirect Cost
Name
University of Chicago
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
Du, Te; Zhou, Guoying; Roizman, Bernard (2013) Modulation of reactivation of latent herpes simplex virus 1 in ganglionic organ cultures by p300/CBP and STAT3. Proc Natl Acad Sci U S A 110:E2621-8
Gu, Haidong; Zheng, Yi; Roizman, Bernard (2013) Interaction of herpes simplex virus ICP0 with ND10 bodies: a sequential process of adhesion, fusion, and retention. J Virol 87:10244-54
Roizman, Bernard; Whitley, Richard J (2013) An inquiry into the molecular basis of HSV latency and reactivation. Annu Rev Microbiol 67:355-74
Zhou, Guoying; Du, Te; Roizman, Bernard (2013) The role of the CoREST/REST repressor complex in herpes simplex virus 1 productive infection and in latency. Viruses 5:1208-18
Zhou, Guoying; Du, Te; Roizman, Bernard (2013) HSV carrying WT REST establishes latency but reactivates only if the synthesis of REST is suppressed. Proc Natl Acad Sci U S A 110:E498-506
Mallon, Stephen; Wakim, Bassam T; Roizman, Bernard (2012) Use of biotinylated plasmid DNA as a surrogate for HSV DNA to identify proteins that repress or activate viral gene expression. Proc Natl Acad Sci U S A 109:E3549-57
Kalamvoki, Maria; Gu, Haidong; Roizman, Bernard (2012) Overexpression of the ubiquitin-specific protease 7 resulting from transfection or mutations in the ICP0 binding site accelerates rather than depresses herpes simplex virus 1 gene expression. J Virol 86:12871-8
Du, Te; Zhou, Guoying; Roizman, Bernard (2012) Induction of apoptosis accelerates reactivation of latent HSV-1 in ganglionic organ cultures and replication in cell cultures. Proc Natl Acad Sci U S A 109:14616-21
Roizman, Bernard (2011) The checkpoints of viral gene expression in productive and latent infection: the role of the HDAC/CoREST/LSD1/REST repressor complex. J Virol 85:7474-82
Roizman, Bernard; Zhou, Guoying; Du, Te (2011) Checkpoints in productive and latent infections with herpes simplex virus 1: conceptualization of the issues. J Neurovirol 17:512-7

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