title: The structural protein ODV-EC27 of Autographa californica nucleopolyhedrovirus is a multifunctional viral cyclin.
abstract: Two major characteristics of baculovirus infection are arrest of the host cell at G2/M phase of the cell cycle with continuing viral DNA replication. We show that Autographa californica nucleopolyhedrovirus (AcMNPV) encodes for a multifunctional cyclin that may partially explain the molecular basis of these important characteristics of AcMNPV (baculovirus) infection. Amino acids 80-110 of the viral structural protein ODV-EC27 (-EC27) demonstrate 25-30% similarity with cellular cyclins within the cyclin box. Immunoprecipitation results using antibodies to -EC27 show that -EC27 can associate with either cdc2 or cdk6 resulting in active kinase complexes that can phosphorylate histone H1 and retinoblastoma protein in vitro. The cdk6-EC27 complex also associates with proliferating cell nuclear antigen (PCNA) and we demonstrate that PCNA is a structural protein of both the budded virus and the occlusion-derived virus. These results suggest that -EC27 can function as a multifunctional cyclin: when associated with cdc2, it exhibits cyclin B-like activity; when associated with cdk6, the complex possesses cyclin D-like activity and binds PCNA. The possible roles of such a multifunctional cyclin during the life cycle of baculovirus are discussed, along with potential implications relative to the expression of functionally authentic recombinant proteins by using baculovirus-infected cells.
authors.affiliation: Department of Entomology, Texas A&M University, College Station, TX 77843-2475, USA.
authors.forename: M
authors.initials: M
authors.lastname: Belyavskyi
authors.forename: S C
authors.initials: SC
authors.lastname: Braunagel
authors.forename: M D
authors.initials: MD
authors.lastname: Summers
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016367:Baculoviridae / Q000378:metabolism; D016203:CDC2 Protein Kinase; D036022:Capsid Proteins; D002999:Clone Cells / Q000648:ultrastructure; D019926:Cyclin B / Q000378:metabolism; D056741:Cyclin D; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases; D016213:Cyclins / Q000737:chemistry* / Q000378:metabolism; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000737:chemistry*; D010766:Phosphorylation; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D018411:Spodoptera / Q000378:metabolism; D014764:Viral Proteins / Q000737:chemistry; D015678:Viral Structural Proteins / Q000737:chemistry*
chemical_list: C101553:Ac-odv-ec27 protein, Autographa californica nucleopolyhedrovirus; D036022:Capsid Proteins; D019926:Cyclin B; D056741:Cyclin D; D016213:Cyclins; D018809:Proliferating Cell Nuclear Antigen; D014764:Viral Proteins; D015678:Viral Structural Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D016203:CDC2 Protein Kinase; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases