title: The amphibians Xenopus laevis and Silurana tropicalis possess a family of activating KIR-related Immunoglobulin-like receptors.
abstract: In this study, we searched the amphibian species Xenopus laevis and Silurana (Xenopus) tropicalis for the presence of genes homologous to mammalian KIRs and avian CHIRs (KRIR family). By experimental and computational procedures, we identified four related ILR (Ig-like Receptors) genes in S. tropicalis and three in X. laevis. ILRs encode type I transmembrane receptors with 3-4 Ig-like extracellular domains. All predicted ILR proteins appear to be activating receptors. ILRs have a broad expression pattern, the gene transcripts were found in both lymphoid and non-lymphoid tissues. Phylogenetic analysis shows that the amphibian KRIR family receptors evolved independently from their mammalian and avian counterparts. The only conserved structural element of tetrapod KRIRs is the NxxR motif-containing transmembrane domain that facilitates association with FcRgamma subunit. Our findings suggest that if KRIRs of various vertebrates have any common function at all, such a function is activating rather than inhibitory.
authors.affiliation: Laboratory of Immunogenetics, Division of Molecular and Cellular Biology, Institute of Chemical Biology and Fundamental Medicine, Prospekt Lavrentyeva 8, Novosibirsk 630090, Russian Federation. sgus@bionet.nsc.ru
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Guselnikov
authors.forename: Evdokiya S
authors.initials: ES
authors.lastname: Reshetnikova
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Najakshin
authors.forename: Ludmila V
authors.initials: LV
authors.lastname: Mechetina
authors.forename: Jacques
authors.initials: J
authors.lastname: Robert
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Taranin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D015139:Blotting, Southern; D002645:Chickens; D057225:Data Mining; D005434:Flow Cytometry; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D054340:Receptors, KIR / Q000235:genetics* / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014981:Xenopus / Q000235:genetics* / Q000276:immunology*; D029867:Xenopus Proteins / Q000235:genetics* / Q000276:immunology*; D014982:Xenopus laevis
chemical_list: D054340:Receptors, KIR; D029867:Xenopus Proteins