Molecular Characterization of 33K Protein of Bovine Adenovirus Type 3
Date
2003-10
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ORCID
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Degree Level
Masters
Abstract
The objective of the present study was to characterize the 33K protein of Bovine Adenovirus type 3 (BAV3). BAV3, a member of adenoviridae subgroup 1, encodes a non-structural 33K protein of 274 amino-acids during the late phase (L6) of virus replication. 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 from in vitro translated and transcribed mRNA. However, three proteins of 42kDa, 38kDa and 33kDa were immunoprecipitated in BAV3 infected cells. To determine the role of this protein in virus replication, a recombinant BAV3 (BAV33KS1) containing inactivated of 33K (a stop codon SI was created at the 7th amino acid of the 33K ORF) was constructed. Although BAV33KS1 could be isolated, mutant virus showed a severe defect in the production of progeny virus. The analysis of infected cells indicates that there appears to be no effect of this protein inactivation on early & late viral gene expression and capsid formation. However, the formation of mature capsids was significantly reduced in BAV33KS1 infected cells. The reduced titer of mutant BAV3 virus may be attributed to the defect in virus assembly. Surprisingly, the lethality of the virus was observed upon transfecting the viral DNA containing a stop codon (S2) created at amino-acid 97 in the 33K ORF. Taken together, our results suggest that the 33K protein of BAV3 plays a role in virus assembly including DNA encapsidation.
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Degree
Master of Science (M.Sc.)
Department
Veterinary Microbiology
Program
Veterinary Microbiology