title: The BIR and BIR-like domains of Bombyx mori nucleopolyhedrovirus IAP2 protein are required for efficient viral propagation.
abstract: The baculovirus Bombyx mori nucleopolyhedrovirus (BmNPV) possesses two genes, iap1 and iap2, which encode inhibitor of apoptosis (IAP) proteins. We previously showed that although both genes are dispensable for viral propagation, iap2 is required for efficient viral propagation in cultured cells. BmNPV IAP2 contains three putative functional domains: a baculovirus IAP repeat (BIR), a BIR-like (BIRL) domain, and a RING finger domain. To identify the domain affecting viral growth, we generated a series of BmNPV bacmids expressing iap2 derivatives lacking one or two domains, or possessing a single amino acid substitution to abolish IAP2 ubiquitin ligase activity. We examined their properties in both cultured cells and B. mori larvae. We found that either the BIR or BIRL domain of IAP2 plays an important role in BmNPV infection, and that the RING finger domain, which is required for ubiquitin ligase activity, does not greatly contribute to BmNPV propagation. This is the first study to identify functional domains of the baculovirus IAP2 protein.
authors.affiliation: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Hanako
authors.initials: H
authors.lastname: Ito
authors.affiliation: Laboratory of Applied Molecular Entomology, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan.
authors.forename: Hisanori
authors.initials: H
authors.lastname: Bando
authors.affiliation: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Shimada
authors.affiliation: Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan. Electronic address: katsuma@ss.ab.a.u-tokyo.ac.jp.
authors.forename: Susumu
authors.initials: S
authors.lastname: Katsuma
mesh_terms: D000818:Animals; D012831:Bombyx / Q000821:virology*; D002478:Cells, Cultured; D051034:Inhibitor of Apoptosis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017924:Nucleopolyhedroviruses / Q000254:growth & development* / Q000378:metabolism*; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
chemical_list: D051034:Inhibitor of Apoptosis Proteins; D014764:Viral Proteins; C086430:inhibitor of apoptosis, Nucleopolyhedrovirus
keywords: BIR; Baculovirus; BmNPV; IAP; RING finger; Ubiquitin ligase