title: Expansion and diversification of the signaling capabilities of the CD2/SLAM family in Xenopodinae amphibians.
abstract: We studied the evolution of the CD2 family in tetrapods by extracting and analyzing CD2-like genes from the genome of the amphibian species Silurana (Xenopus) tropicalis. An exhaustive analysis of the genomic and cDNA databases resulted in the identification of at least 70 CD2-like genes. The predicted receptors mostly maintain the typical VC2 ectodomains, but are highly diverse in their C-termini, which suggests a broad range of signaling capacities. Apart from the presumed monomeric receptors with ITSM and/or ITIM motifs, the Silurana family includes secreted proteins. Furthermore, a fraction of the receptors contain a conserved TM subtype with the NxxR motif that is known to promote an association with the FcRγ subunit and that was previously found in the members of the FcR- and KIR-related receptors. The expression analysis of a sample of the genes showed broad tissue distribution and gene-specific expression patterns. Phylogenetic analysis predicted that the CD58, CD150/SLAM, and SLAMF8 genes were maintained as single-copy genes in both mammals and amphibians, while others expanded/contracted in a lineage-specific manner.
authors.affiliation: Laboratory of Immunogenetics, Department of Molecular and Cellular Biology, Institute of Chemical Biology and Fundamental Medicine, Prospekt Lavrentyeva 8, Novosibirsk, 630090, Russia. sguselnikov@mcb.nsc.ru
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Guselnikov
authors.forename: Petr P
authors.initials: PP
authors.lastname: Laktionov
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Najakshin
authors.forename: Konstantin O
authors.initials: KO
authors.lastname: Baranov
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Taranin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000145:classification / Q000235:genetics*; D018801:CD2 Antigens / Q000145:classification / Q000235:genetics*; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D011956:Receptors, Cell Surface / Q000145:classification / Q000235:genetics*; D016415:Sequence Alignment; D015398:Signal Transduction; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1; D014981:Xenopus / Q000235:genetics / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D018801:CD2 Antigens; D011956:Receptors, Cell Surface; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1