title: CR3 complement receptor: cloning and characterization in rainbow trout.
abstract: The beta 2 integrin CR3 is a leukocyte adhesion heterodimeric glycoprotein which functions both as receptor for iC3b and in several cell-cell and cell-substrate adhesion interactions. In order to elucidate the molecular evolution of the CR3 receptor, here we report the cloning and characterization of its beta2 (CD18) and aM (CD11b) subunits in rainbow trout (Oncorhynchus mykiss). The predicted polypeptide sequences of trout CD18 and CD11b-like exhibit 50, 49, or 61% and 25, 25, or 30% identity with human, mouse, and zebrafish orthologs, respectively. The 'domain' architecture of trout CD18 and CD11b-like subunits retains several characteristics of the mammalian ortholog proteins, such as cysteine-rich regions, N-linked glycosylation sites and several proposed domains and signal sequences (von Willebrand factor type A, Integrin alpha, Integrin B tail, EGF, and Transmembrane domain). The tissue expression profiles of trout CR3 subunits diverge from those of mammalian counterparts, showing the kidney as the main source of the trout CD18 and CD11b-like mRNA transcripts. This is the first report of cloning and characterization of the CR3 receptor in low vertebrates.
authors.affiliation: Department of Biology, School of Medicine, University of Patras, Patras, Greece.
authors.forename: Angeliki
authors.initials: A
authors.lastname: Mikrou
authors.forename: Dimitra
authors.initials: D
authors.lastname: Marioli
authors.forename: Anastasios D
authors.initials: AD
authors.lastname: Papanastasiou
authors.forename: Ioannis K
authors.initials: IK
authors.lastname: Zarkadis
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D039481:CD11b Antigen / Q000235:genetics; D018821:CD18 Antigens / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D023061:Gene Order; D016177:Macrophage-1 Antigen / Q000235:genetics*; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000235:genetics* / Q000378:metabolism*; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment
chemical_list: D039481:CD11b Antigen; D018821:CD18 Antigens; D018076:DNA, Complementary; D016177:Macrophage-1 Antigen