Affiliation:
1. Department of Molecular Microbiology
2. Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
Abstract
ABSTRACT
Cytokines regulate viral gene expression with important consequences for viral replication and pathogenesis. Gamma interferon (IFN-γ) is a key regulator of chronic murine gammaherpesvirus 68 (γHV68) infection and a potent inhibitor of γHV68 reactivation from latency. Macrophages are the cell type that is responsive to the IFN-γ-mediated control of γHV68 reactivation; however, the molecular mechanism of this IFN-γ action is undefined. Here we report that IFN-γ inhibits lytic replication of γHV68 in primary bone marrow-derived macrophages and decreases transcript levels for the essential lytic switch gene 50. Interestingly, IFN-γ suppresses the activity of the two known gene 50 promoters, demonstrating that an inflammatory cytokine can directly regulate the promoters for the γHV68 lytic switch gene. Stat1, but not IFN-α/β signaling, is required for IFN-γ action. Moreover, Stat1 deficiency increases basal γHV68 replication, gene 50 expression, and promoter activity. Together, these data identify IFN-γ and Stat1 as being negative regulators of the γHV68 lytic cycle and raise the possibility that γHV68 maintains IFN-γ/Stat1-responsive gene 50 promoters to facilitate cell-extrinsic control over the interchange between the lytic and latent cycles.
Publisher
American Society for Microbiology
Subject
Virology,Insect Science,Immunology,Microbiology
Cited by
42 articles.
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