title: Role of bovine adenovirus-3 33K protein in viral replication.
abstract: The L6 region of bovine adenovirus type (BAdV)-3 encodes a nonstructural protein named 33K. To identify and characterize the 33K protein, rabbit polyclonal antiserum was raised against a 33K-GST fusion protein expressed in bacteria. Anti-33K serum immunoprecipitated a protein of 42 kDa in in vitro translated and transcribed mRNA of 33K. However, three proteins of 42, 38, and 33 kDa were detected in BAdV-3 infected cells. To determine the role of this protein in virus replication, a recombinant BAV-33S1 containing insertional inactivation of 33K (a stop codon created at the seventh amino acid of 33K ORF) was constructed. Although BAV-33S1 could be isolated, the mutant showed a severe defect in the production of progeny virus. Inactivation of the 33K gene showed no effect on early and late viral gene expression in cells infected with BAV-33S1. However, formation of mature virions was significantly reduced in cells infected with BAV-33S1. Surprisingly, insertional inactivation of 33K at amino acid 97 (pFBAV-33.KS2) proved lethal for virus production. Although expression of early or late genes was not affected, no capsid formation could be observed in mutant DNA-transfected cells. These results suggest that 33K is required for capsid assembly and efficient DNA capsid interaction.
authors.affiliation: Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E3.
authors.forename: Vikas
authors.initials: V
authors.lastname: Kulshreshtha
authors.forename: Lorne A
authors.initials: LA
authors.lastname: Babiuk
authors.forename: Suresh K
authors.initials: SK
authors.lastname: Tikoo
mesh_terms: D000818:Animals; D001483:Base Sequence; D002213:Capsid / Q000378:metabolism; D002417:Cattle; D002460:Cell Line; D017921:Mastadenovirus / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity / Q000502:physiology*; D008969:Molecular Sequence Data; D011817:Rabbits; D011995:Recombination, Genetic; D014162:Transfection; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*; D019065:Virus Assembly; D014779:Virus Replication / Q000502:physiology*
chemical_list: D017361:Viral Nonstructural Proteins