title: Proteolytic Cleavage of Bovine Adenovirus 3-Encoded pVIII.
abstract: Proteolytic maturation involving cleavage of one nonstructural and six structural precursor proteins including pVIII by adenovirus protease is an important aspect of the adenovirus life cycle. The pVIII encoded by bovine adenovirus 3 (BAdV-3) is a protein of 216 amino acids and contains two potential protease cleavage sites. Here, we report that BAdV-3 pVIII is cleaved by adenovirus protease at both potential consensus protease cleavage sites. Usage of at least one cleavage site appears essential for the production of progeny BAdV-3 virions as glycine-to-alanine mutation of both protease cleavage sites appears lethal for the production of progeny virions. However, mutation of a single protease cleavage site of BAdV-3 pVIII significantly affects the efficient production of infectious progeny virions. Further analysis revealed no significant defect in endosome escape, genome replication, capsid formation, and virus assembly. Interestingly, cleavage of pVIII at both potential cleavage sites appears essential for the production of stable BAdV-3 virions as BAdV-3 expressing pVIII containing a glycine-to-alanine mutation of either of the potential cleavage sites is thermolabile, and this mutation leads to the production of noninfectious virions.IMPORTANCEHere, we demonstrated that the BAdV-3 adenovirus protease cleaves BAdV-3 pVIII at both potential protease cleavage sites. Although cleavage of pVIII at one of the two adenoviral protease cleavage sites is required for the production of progeny virions, the mutation of a single cleavage site of pVIII affects the efficient production of infectious progeny virions. Further analysis indicated that the mutation of a single protease cleavage site (glycine to alanine) of pVIII produces thermolabile virions, which leads to the production of noninfectious virions with disrupted capsids. We thus provide evidence about the requirement of proteolytic cleavage of pVIII for production of infectious progeny virions. We feel that our study has significantly advanced the understanding of the requirement of adenovirus protease cleavage of pVIII.
authors.affiliation: VIDO-InterVac, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.|Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Amit
authors.initials: A
authors.lastname: Gaba
authors.affiliation: VIDO-InterVac, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.|Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Lisanework
authors.initials: L
authors.lastname: Ayalew
authors.affiliation: VIDO-InterVac, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Niraj
authors.initials: N
authors.lastname: Makadiya
authors.affiliation: VIDO-InterVac, University of Saskatchewan, Saskatoon, Saskatchewan, Canada Suresh.tik@usask.ca.|Department of Veterinary Microbiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.|Vaccinology and Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Suresh
authors.initials: S
authors.lastname: Tikoo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D036022:Capsid Proteins / Q000737:chemistry / Q000378:metabolism*; D002417:Cattle; D002460:Cell Line; D004261:DNA Replication; D017921:Mastadenovirus / Q000201:enzymology* / Q000378:metabolism* / Q000502:physiology; D010447:Peptide Hydrolases / Q000378:metabolism; D059748:Proteolysis; D014764:Viral Proteins / Q000378:metabolism; D019065:Virus Assembly; D014779:Virus Replication
chemical_list: D036022:Capsid Proteins; D014764:Viral Proteins; D010447:Peptide Hydrolases
keywords: BAdV-3; adenovirus protease; pVIII; proteolytic cleavage; thermolabile