title: Ubiquitin ligase activities of Bombyx mori nucleopolyhedrovirus RING finger proteins.
abstract: The genome of Bombyx mori nucleopolyhedrovirus (BmNPV) is predicted to contain six RING finger proteins: IAP1, ORF35, IAP2, CG30, IE2, and PE38. Several other members of the RING finger family have recently been shown to have the ubiquitin-ligase (E3) activity. We thus examined whether BmNPV RING finger proteins have the E3 activity. In vitro ubiquitination assay with the rabbit reticulocyte lysates and BmNPV RING finger proteins fused with maltose-binding protein (MBP) showed that four of them (IAP2, IE2, PE38, and CG30) were polyubiquitinated in the presence of zinc ion. Furthermore, MBP-IAP2, MBP-IE2, and MBP-PE38 were able to reconstitute ubiquitination activity in cooperation with the Ubc4/5 subfamily of ubiquitin-conjugating enzymes. Mutational analysis also showed that ubiquitination activity of MBP-IAP2, MBP-IE2, and MBP-PE38 were dependent on their RING finger motif. Therefore, these results suggest that IAP2, IE2, and PE38 may function as E3 enzymes during BmNPV infection.
authors.affiliation: Laboratory of Molecular Entomology and Baculovirology, Wako, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Imai
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Matsuda
authors.forename: Keiji
authors.initials: K
authors.lastname: Tanaka
authors.forename: Akihiko
authors.initials: A
authors.lastname: Nakano
authors.forename: Shogo
authors.initials: S
authors.lastname: Matsumoto
authors.forename: WonKyung
authors.initials: W
authors.lastname: Kang
mesh_terms: D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000821:virology*; D002352:Carrier Proteins / Q000378:metabolism*; D017931:DNA Primers; D008025:Ligases / Q000378:metabolism*; D017924:Nucleopolyhedroviruses / Q000201:enzymology*; D025801:Ubiquitin / Q000378:metabolism*; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D017931:DNA Primers; D025801:Ubiquitin; D014764:Viral Proteins; D008025:Ligases