title: Autographa californica multiple nucleopolyhedrovirus ORF11 is essential for budded-virus production and occlusion-derived-virus envelopment.
abstract: ORF11 (ac11) of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a highly conserved gene with unknown function. To determine the role of ac11 in the baculovirus life cycle, an ac11 knockout mutant of AcMNPV, Ac11KO, was constructed. Northern blot and 5' rapid amplification of cDNA ends (RACE) analyses revealed that ac11 is an early gene in the life cycle. Microscopy, titration assays, and Western blot analysis revealed that budded viruses (BVs) were not produced in Ac11KO-transfected Sf9 cells. However, quantitative PCR (qPCR) analysis demonstrated that the deletion of ac11 did not affect viral DNA replication. Furthermore, electron microscopy revealed that there was no nucleocapsid in the cytoplasm or plasma membrane of Ac11KO-transfected cells, which demonstrates that the defect in BV production in Ac11KO-transfected cells is due to the inefficient egress of nucleocapsids from the nucleus to the cytoplasm. In addition, electron microscopy observations showed that the nucleocapsids in the nucleus were not enveloped to form occlusion-derived viruses (ODVs) and that their subsequent embedding into occlusion bodies (OBs) was also blocked in Ac11KO-transfected cells, demonstrating that ac11 is required for ODV envelopment. These results therefore demonstrate that ac11 is an early gene that is essential for BV production and ODV envelopment.
  
  
  OBJECTIVE
  Baculoviruses have been extensively used not only as specific, environmentally benign insecticides but also as helper-independent protein expression vectors. Although the function of baculovirus genes in viral replication has been studied by using gene knockout technology, the functions of more than one-third of viral genes, which include some highly conserved genes, are still unknown. In this study, ac11 was proven to play a crucial role in BV production and ODV envelopment. These results will lead to a better understanding of baculovirus infection cycles.
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, China Jiangxi-OAI Joint Research Institute, Nanchang University, Nanchang, China.
authors.forename: Xue Ying
authors.initials: XY
authors.lastname: Tao
authors.affiliation: Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea.
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Choi
authors.affiliation: Department of Agricultural Biotechnology, College of Agriculture and Life Science, Seoul National University, Seoul, South Korea.
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Kim
authors.affiliation: Department of Agricultural Biotechnology, College of Agriculture and Life Science, Seoul National University, Seoul, South Korea.
authors.forename: Saes Byeol
authors.initials: SB
authors.lastname: An
authors.affiliation: Department of Agricultural Biotechnology, College of Agriculture and Life Science, Seoul National University, Seoul, South Korea.
authors.forename: Qin
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Agricultural Biotechnology, College of Agriculture and Life Science, Seoul National University, Seoul, South Korea.
authors.forename: Song Eun
authors.initials: SE
authors.lastname: Kim
authors.affiliation: Department of Agricultural Biotechnology, College of Agriculture and Life Science, Seoul National University, Seoul, South Korea.
authors.forename: Seok Hee
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Agricultural Biotechnology, College of Agriculture and Life Science, Seoul National University, Seoul, South Korea.
authors.forename: Jong Hoon
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju, South Korea.
authors.forename: Soo Dong
authors.initials: SD
authors.lastname: Woo
authors.affiliation: College of Natural Resources and Life Science, Dong-A University, Pusan, South Korea.
authors.forename: Byung Rae
authors.initials: BR
authors.lastname: Jin
authors.affiliation: Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, South Korea Department of Agricultural Biotechnology, College of Agriculture and Life Science, Seoul National University, Seoul, South Korea btrus@snu.ac.kr.
authors.forename: Yeon Ho
authors.initials: YH
authors.lastname: Je
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000821:virology; D003593:Cytoplasm / Q000821:virology; D055786:Gene Knockout Techniques; D008854:Microscopy, Electron; D019251:Nucleocapsid / Q000648:ultrastructure; D017924:Nucleopolyhedroviruses / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D060888:Real-Time Polymerase Chain Reaction; D061987:Sf9 Cells; D018411:Spodoptera; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D019065:Virus Assembly; D057074:Virus Release; D014779:Virus Replication
chemical_list: D014764:Viral Proteins