Vaccinia virus has a genome of about 185,000 base pairs that encodes approximately 200 polypeptides. These genes are expressed within the cytoplasm in a coordinated fashion, so that some polypeptides are made before, and others after, DNA replication. Enzymes and factors needed for early transcription are packaged within the infectious particle, while those needed for late transcription are present in the cytoplasm of infected cells.
The aim of this project is to determine the mechanisms regulating gene expression. Progress in understanding early and late transcription has been made this past year. Several viral genes required for transcription were identified. These include an RNA polymerase subunit of 18,000 daltons, both subunits of the early transcription factor VETF, and three transactivators of late gene expression. Evidence was obtained for a cascade mechanism of gene regulation in which the early transcription factors are made late during the previous infection cycle and packaged in virions, the intermediate factors are made early in infection, and the late factors are made at intermediate times. The DNA present in the infecting virus particle serves as a template for transcription of early genes but naked or newly replicated DNA is required as a template for intermediate and late genes.

National Institute of Health (NIH)
National Institute of Allergy and Infectious Diseases (NIAID)
Intramural Research (Z01)
Project #
Application #
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
United States
Zip Code
De Silva, Frank S; Paran, Nir; Moss, Bernard (2009) Products and substrate/template usage of vaccinia virus DNA primase. Virology 383:136-41
Katsafanas, George C; Moss, Bernard (2007) Colocalization of transcription and translation within cytoplasmic poxvirus factories coordinates viral expression and subjugates host functions. Cell Host Microbe 2:221-8
Parrish, Susan; Moss, Bernard (2007) Characterization of a second vaccinia virus mRNA-decapping enzyme conserved in poxviruses. J Virol 81:12973-8
Hebben, Matthias; Brants, Jan; Birck, Catherine et al. (2007) High level protein expression in mammalian cells using a safe viral vector: modified vaccinia virus Ankara. Protein Expr Purif 56:269-78
Parrish, Susan; Resch, Wolfgang; Moss, Bernard (2007) Vaccinia virus D10 protein has mRNA decapping activity, providing a mechanism for control of host and viral gene expression. Proc Natl Acad Sci U S A 104:2139-44
Garcia, Alonzo D; Otero, Joel; Lebowitz, Jacob et al. (2006) Quaternary structure and cleavage specificity of a poxvirus holliday junction resolvase. J Biol Chem 281:11618-26
Parrish, Susan; Moss, Bernard (2006) Characterization of a vaccinia virus mutant with a deletion of the D10R gene encoding a putative negative regulator of gene expression. J Virol 80:553-61
Domi, Arban; Moss, Bernard (2005) Engineering of a vaccinia virus bacterial artificial chromosome in Escherichia coli by bacteriophage lambda-based recombination. Nat Methods 2:95-7
De Silva, Frank S; Moss, Bernard (2005) Origin-independent plasmid replication occurs in vaccinia virus cytoplasmic factories and requires all five known poxvirus replication factors. Virol J 2:23
Katsafanas, George C; Moss, Bernard (2004) Vaccinia virus intermediate stage transcription is complemented by Ras-GTPase-activating protein SH3 domain-binding protein (G3BP) and cytoplasmic activation/proliferation-associated protein (p137) individually or as a heterodimer. J Biol Chem 279:52210-7

Showing the most recent 10 out of 25 publications