title: Orgyia pseudotsugata baculovirus p10 and polyhedron envelope protein genes: analysis of their relative expression levels and role in polyhedron structure.
abstract: To investigate the regulation of p10 and polyhedron envelope protein (PEP) gene expression and their role in polyhedron development, Orgyia pseudotsugata multinucleocapsid nuclear polyhedrosis viruses lacking these genes were constructed. Recombinant viruses were produced, in which the p10 gene, the PEP gene or both genes were disrupted with the beta-glucuronidase (GUS) or beta-galactosidase (lacZ) genes. GUS activity under the control of the PEP protein promoter was observed later in infection and its maximal expression was less than 10% the level for p10 promoter-GUS constructs. Tissues from O. pseudotsugata larvae infected with these recombinants were examined by electron microscopy. Cells from insects infected with the p10- viruses lacked p10-associated fibrillar structures, but fragments of polyhedron envelope-like structures were observed on the surface of some polyhedra. Immunogold labelling of cells infected with the p10-GUS+ virus with an antibody directed against PEP showed that the PEP was concentrated at the surface of polyhedra. Although polyhedra produced by p10 and PEP gene deletion mutants demonstrated what appeared to be a polyhedron envelope by transmission electron microscopy, scanning electron microscopy showed that they had irregular, pitted surfaces that were different from wild-type polyhedra. These data suggested that both p10 and PEP are important for the proper formation of the periphery of polyhedra.
authors.affiliation: Department of Agricultural Chemistry, Agricultural & Life Sciences 1007, Oregon State University, Corvallis 97331-7301.
authors.forename: C H
authors.initials: CH
authors.lastname: Gross
authors.forename: R L
authors.initials: RL
authors.lastname: Russell
authors.forename: G F
authors.initials: GF
authors.lastname: Rohrmann
mesh_terms: D000818:Animals; D001483:Base Sequence; D015967:Gene Expression Regulation, Viral; D005814:Genes, Viral / Q000235:genetics; D005966:Glucuronidase / Q000096:biosynthesis / Q000235:genetics; D007181:Inclusion Bodies, Viral / Q000502:physiology* / Q000648:ultrastructure; D007313:Insecta / Q000382:microbiology; D007814:Larva / Q000382:microbiology; D008855:Microscopy, Electron, Scanning; D016253:Microscopy, Immunoelectron; D008869:Microtubule-Associated Proteins / Q000502:physiology*; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D000077183:Occlusion Body Matrix Proteins; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D014764:Viral Proteins / Q000502:physiology*; D015678:Viral Structural Proteins
chemical_list: D008869:Microtubule-Associated Proteins; D000077183:Occlusion Body Matrix Proteins; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D015678:Viral Structural Proteins; C009829:polyhedrin protein, Nucleopolyhedrovirus; C078072:p10 protein, Baculovirus; D005966:Glucuronidase