title: Autographa californica multiple nucleopolyhedrovirus gene ac81 is required for nucleocapsid envelopment.
abstract: Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is a highly pathogenic Baculoviridae that targets insects, whose core gene, ac81, has an unknown function. To determine the role of ac81 in the life cycle of AcMNPV, an ac81-knockout (Ac-81KO-GP) was constructed through homologous recombination in Escherichia coli. We determined that no budded virions were produced in Ac-81KO-GP-transfected Sf9 cells, while there was no effect on viral DNA replication. Electron microscopy (EM) analysis revealed that occlusion-derived virions (ODVs) envelopment and the subsequent embedding of virions into occlusion bodies (OBs) were aborted due to ac81 deletion. Interestingly, confocal microscopy and immunofluorescence analysis revealed that Ac81 was predominantly localized to the ring zone of nuclei during the late phase of infection. In addition, Ac81 was localized to the mature and premature ODVs in virus-infected cells within the ring zone as revealed by immuno-electron microscopy (IEM) analysis. Furthermore, we determined that Ac81 contained a functional hydrophobic transmembrane (TM) domain, whose deletion resulted in a phenotype similar to that of Ac-81KO-GP. These results suggest that Ac81 might be a TM protein that played an important role in nucleocapsid envelopment.
authors.affiliation: School of Life Science, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Dong
authors.affiliation: School of Life Science, Sun Yat-Sen University, Guangzhou 510275, China. Electronic address: wangjinw@mail.sysu.edu.cn.
authors.forename: Jinwen
authors.initials: J
authors.lastname: Wang
authors.affiliation: School of Life Science, Sun Yat-Sen University, Guangzhou 510275, China.
authors.forename: Riqiang
authors.initials: R
authors.lastname: Deng
authors.affiliation: School of Life Science, Sun Yat-Sen University, Guangzhou 510275, China. Electronic address: wxz@mail.sysu.edu.cn.
authors.forename: Xunzhang
authors.initials: X
authors.lastname: Wang
mesh_terms: D000818:Animals; D055786:Gene Knockout Techniques; D005814:Genes, Viral; D017924:Nucleopolyhedroviruses / Q000235:genetics* / Q000502:physiology*; D061987:Sf9 Cells; D018411:Spodoptera; D014759:Viral Envelope Proteins / Q000378:metabolism*; D014771:Virion / Q000378:metabolism; D019065:Virus Assembly
chemical_list: D014759:Viral Envelope Proteins
keywords: Budded virions; Core gene; Envelopment; Nucleocapsid; Occlusion-derived virions; ac81