title: Identification and functional characterization of an Rbx1 in an invertebrate Haliotis diversicolor supertexta.
abstract: Rbx1 (RING box1) is an evolutionarily conserved RING-H2 finger protein and belongs to the RING-finger family of Ubiquitin ligase E3, which determines the substrate specificity of ubiquitination and regulates a variety of biological processes. We report here the identification and functional characterization of an Rbx1 homologue in abalone, which we named ab-Rbx1. Ab-Rbx1 contains conserved cysteine/histidine residues which are the characteristics of Rbx proteins. Phylogenetic tree analysis further demonstrated that ab-Rbx1 belongs to the Rbx1 family other than Rbx2 family. Real-time PCR analysis revealed that ab-Rbx1 was ubiquitously expressed in all examined tissues of abalone and the expression level of ab-Rbx1 was significantly induced by mitogenic situation. Immunohistochemical and immunofluorescent staining showed that the ab-Rbx1 was expressed predominantly in epithelial cells and localized both in the cytoplasmic and nuclear compartment. Ubiquitination assay demonstrated that ab-Rbx1 had ubiquitin ligase activity and could auto-ubiquitinated itself. These results suggest that ab-Rbx1 is an Rbx1 homologue and may be indirectly involved in the immune response of abalone through ubiquitination.
authors.affiliation: College of Agronomy, Henan Agricultural University, 63 Nongye Road, Zhengzhou 450002, PR China.
authors.forename: Liuji
authors.initials: L
authors.lastname: Wu
authors.forename: Xinzhong
authors.initials: X
authors.lastname: Wu
authors.forename: Li
authors.initials: L
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D049851:Gastropoda / Q000145:classification / Q000235:genetics* / Q000276:immunology*; D005786:Gene Expression Regulation; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D011994:Recombinant Proteins; D016415:Sequence Alignment
chemical_list: D002352:Carrier Proteins; D011994:Recombinant Proteins