In recent years it has become increasingly clear that transcription elongation is an important control point for regulation of eucaryotic gene expression. Our recent work demonstrates that postreplicative gene transcription elongation is regulated during vaccinia virus infection. A study of this regulation is important for understanding regulation of vaccina virus gene expression in particular, and the system may prove to be an important model for study of regulation of transcription elongation in eucaryotes in general. The goal of this project is to understand the regulation of vaccinia virus postreplicative (intermediate and late) gene transcription elongation. The project centers on two vaccinia genes, G2R and A18R, which seem to regulate postreplicative gene transcription elongation with complementing activities. Genetic experiments indicate that the A18R gene product, a DNA helicase, restricts the processivity of the viral RNA polymerase and therefore acts as negative transcription elongation factor, while the G2R gene product enhances the processivity of the viral RNA polymerase and therefore acts as a positive transcription elongation factor. Biochemical and genetic experiments implicate several other viral gene products in the regulation of postreplicative transcription elongation, including a viral late transcription initiation factor (H5R), a viral poly A polymerase subunit (J3R), and two viral RNA polymerase subunits (J4R and A24R). Our working hypothesis is that these gene products work together, perhaps as a transcription elongation complex, to regulate formation of 3' ends of intermediate and late vaccinia viral mRNAs. We propose to test, refine, and extend this hypothesis through 1) an in vitro transcription elongation assay, 2) phenotypic analysis of existing virus mutants defective in transcription elongation, and 3) isolation and characterization of additional elongation defective mutants.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Research Project (R01)
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Experimental Virology Study Section (EVR)
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Meegan, James M
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University of Florida
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Tate, Jessica; Boldt, Rachel L; McFadden, Baron D et al. (2016) Biochemical analysis of the multifunctional vaccinia mRNA capping enzyme encoded by a temperature sensitive virus mutant. Virology 487:27-40
D'Costa, Susan M; Bainbridge, Travis W; Kato, Sayuri E et al. (2010) Vaccinia H5 is a multifunctional protein involved in viral DNA replication, postreplicative gene transcription, and virion morphogenesis. Virology 401:49-60
Shatzer, Amber N; Kato, Sayuri E M; Condit, Richard C (2008) Phenotypic analysis of a temperature sensitive mutant in the large subunit of the vaccinia virus mRNA capping enzyme. Virology 375:236-52
D'Costa, Susan M; Bainbridge, Travis W; Condit, Richard C (2008) Purification and properties of the vaccinia virus mRNA processing factor. J Biol Chem 283:5267-75
Cresawn, Steven G; Condit, Richard C (2007) A targeted approach to identification of vaccinia virus postreplicative transcription elongation factors: genetic evidence for a role of the H5R gene in vaccinia transcription. Virology 363:333-41
Cresawn, Steven G; Prins, Cindy; Latner, Donald R et al. (2007) Mapping and phenotypic analysis of spontaneous isatin-beta-thiosemicarbazone resistant mutants of vaccinia virus. Virology 363:319-32
D'Costa, Susan M; Antczak, James B; Pickup, David J et al. (2004) Post-transcription cleavage generates the 3' end of F17R transcripts in vaccinia virus. Virology 319:1-11
Kato, Sayuri E M; Strahl, Audra L; Moussatche, Nissin et al. (2004) Temperature-sensitive mutants in the vaccinia virus 4b virion structural protein assemble malformed, transcriptionally inactive intracellular mature virions. Virology 330:127-46
Lackner, Cari A; D'Costa, Susan M; Buck, Charles et al. (2003) Complementation analysis of the dales collection of vaccinia virus temperature-sensitive mutants. Virology 305:240-59
Latner, Donald R; Thompson, Joseph M; Gershon, Paul D et al. (2002) The positive transcription elongation factor activity of the vaccinia virus J3 protein is independent from its (nucleoside-2'-O-) methyltransferase and poly(A) polymerase stimulatory functions. Virology 301:64-80

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