Viruses use a wide spectrum of molecular mechanisms to favor their own gene expression in the complex environment of an infected host cell. Recent advances suggest that viral regulation of cellular RNA decay pathways is more common than previously appreciated. For example, several factors in the Kaposi's sarcoma-associated herpesvirus (KSHV) have been demonstrated to regulate host or viral RNA turnover rates. In this proposal, a role for the KSHV ORF57 protein in viral transcript stability is examined. ORF57 is a lytic phase protein that is essential for viral replication and has been reported to affect a wide variety of nuclear events in mRNA biogenesis, but its molecular mechanisms remain unknown. The experiments in this proposal are designed to test the hypothesis that ORF57 binds to nuclear RNAs and protects them from cellular RNA decay pathways. Specifically, the studies described here will elucidate the molecular mechanisms of ORF57 nuclear function by examining 1) the effects of ORF57 on nuclear stability of viral mRNAs, 2) the relationship between RNA binding and ORF57 function, and 3) the roles of ORF57 RNA-binding and stability activities in the context of viral lytic infection. Understanding the molecular mechanism of ORF57 is fundamental to understanding the biology of KSHV, the causative agent for Kaposi's sarcoma, primary effusion lymphoma (PEL), and some types of multicentric Castleman's disease (MCD). An appreciation of ORF57 molecular mechanisms may lead to novel therapeutic approaches and bolster knowledge of the pathways important for controlling tumorigenesis. Thus, by revealing the mechanisms of ORF57 function, these studies will provide molecular insights into this important human pathogen and into the biology of its human host cells.

Public Health Relevance

Kaposi's sarcoma-associated herpesvirus (KSHV) causes several malignancies including Kaposi's sarcoma and certain lymphoproliferative disorders. This proposal examines specific mechanisms of KSHV gene regulation essential for viral replication. A deeper understanding of KSHV gene regulation will lead to a more complete knowledge of this important human pathogen and may reveal aspects of gene regulation in its human host cell.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI081710-05
Application #
8663175
Study Section
Virology - A Study Section (VIRA)
Program Officer
Beisel, Christopher E
Project Start
2010-06-01
Project End
2015-05-31
Budget Start
2014-06-01
Budget End
2015-05-31
Support Year
5
Fiscal Year
2014
Total Cost
$330,244
Indirect Cost
$122,125
Name
University of Texas Sw Medical Center Dallas
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
800771545
City
Dallas
State
TX
Country
United States
Zip Code
75390
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Bresson, Stefan M; Conrad, Nicholas K (2013) The human nuclear poly(a)-binding protein promotes RNA hyperadenylation and decay. PLoS Genet 9:e1003893
Hunter, Olga V; Sei, Emi; Richardson, R Blake et al. (2013) Chromatin immunoprecipitation and microarray analysis suggest functional cooperation between Kaposi's Sarcoma-associated herpesvirus ORF57 and K-bZIP. J Virol 87:4005-16
Grammel, Markus; Hang, Howard; Conrad, Nicholas K (2012) Chemical reporters for monitoring RNA synthesis and poly(A) tail dynamics. Chembiochem 13:1112-5
Stubbs, Sarah H; Hunter, Olga V; Hoover, Ashley et al. (2012) Viral factors reveal a role for REF/Aly in nuclear RNA stability. Mol Cell Biol 32:1260-70
Sei, Emi; Conrad, Nicholas K (2011) Delineation of a core RNA element required for Kaposi's sarcoma-associated herpesvirus ORF57 binding and activity. Virology 419:107-16