title: The Autographa californica multiple nucleopolyhedrovirus ORF78 is essential for budded virus production and general occlusion body formation.
abstract: ORF78 (ac78) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a baculovirus core gene of unknown function. To determine the role of ac78 in the baculovirus life cycle, an AcMNPV mutant with ac78 deleted, Ac78KO, was constructed. Quantitative PCR analysis revealed that ac78 is a late gene in the viral life cycle. After transfection into Spodoptera frugiperda cells, Ac78KO produced a single-cell infection phenotype, indicating that no infectious budded viruses (BVs) were produced. The defect in BV production was also confirmed by both viral titration and Western blotting. However, viral DNA replication was unaffected, and occlusion bodies were formed. An analysis of BVs and occlusion-derived viruses (ODVs) revealed that AC78 is associated with both forms of the virions and is an envelope structural protein. Electron microscopy revealed that AC78 also plays an important role in the embedding of ODV into the occlusion body. The results of this study demonstrate that AC78 is a late virion-associated protein and is essential for the viral life cycle.
authors.affiliation: Department of Agricultural Biotechnology, College of Agriculture and Life Science, Seoul National University, Seoul, South Korea.
authors.forename: Xue Ying
authors.initials: XY
authors.lastname: Tao
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Kim
authors.forename: Joo Hyun
authors.initials: JH
authors.lastname: Lee
authors.forename: Qin
authors.initials: Q
authors.lastname: Liu
authors.forename: Song Eun
authors.initials: SE
authors.lastname: Kim
authors.forename: Saes Byeol
authors.initials: SB
authors.lastname: An
authors.forename: Seok Hee
authors.initials: SH
authors.lastname: Lee
authors.forename: Soo Dong
authors.initials: SD
authors.lastname: Woo
authors.forename: Byung Rae
authors.initials: BR
authors.lastname: Jin
authors.forename: Yeon Ho
authors.initials: YH
authors.lastname: Je
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure / Q000821:virology; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics; D017353:Gene Deletion; D020869:Gene Expression Profiling; D020043:Genes, Essential; D045586:Intranuclear Inclusion Bodies / Q000378:metabolism / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D017924:Nucleopolyhedroviruses / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D017422:Sequence Analysis, DNA; D061987:Sf9 Cells; D018411:Spodoptera; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D057074:Virus Release; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D014764:Viral Proteins