title: Cloning of the IgM heavy chain of the bottlenose dolphin (Tursiops truncatus), and initial analysis of VH gene usage.
abstract: Clones encoding the dolphin IgM heavy (micro) chain gene were isolated from a cDNA library of peripheral blood leukocytes. Genomic Southern blot analyses showed that the dolphin IGHM gene is most likely present in a single copy, and its sequence shows greatest similarity to those of the IGHM gene of the sheep, pig and cow, evolutionarily related artiodactyls. The transmembrane (TM) form of the IGHM chain was isolated by 3' RACE. While showing similarities to the TM regions of other mammalian IGHM chains, the highly conserved Ser residue of the CART motif is substituted with a Gly in the dolphin. In contrast to the pig and cow, which utilize only a single VH family, the dolphin expresses at least two distinct VH families, belonging to the mammalian VH clans I and III. At least two JH genes were identified in the dolphin. Some CDR3 regions of the dolphin VH are long (up to 21 amino acids), and contain multiple Cys residues, hypothesized to stabilize the CDR3 structure through disulfide bond formation.
authors.affiliation: Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Avenue, P.O. Box 250509, Charleston, SC 29425, USA.
authors.forename: Mats L
authors.initials: ML
authors.lastname: Lundqvist
authors.forename: Kathleen E
authors.initials: KE
authors.lastname: Kohlberg
authors.forename: Holly A
authors.initials: HA
authors.lastname: Gefroh
authors.forename: Philippe
authors.initials: P
authors.lastname: Arnaud
authors.forename: Darlene L
authors.initials: DL
authors.lastname: Middleton
authors.forename: Tracy A
authors.initials: TA
authors.lastname: Romano
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Warr
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D018076:DNA, Complementary / Q000737:chemistry; D004289:Dolphins / Q000235:genetics / Q000276:immunology*; D015723:Gene Library; D005803:Genes, Immunoglobulin / Q000235:genetics*; D007143:Immunoglobulin Heavy Chains / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D007075:Immunoglobulin M / Q000235:genetics* / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D008969:Molecular Sequence Data; D010802:Phylogeny; D012313:RNA / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D007135:Immunoglobulin Variable Region; D012313:RNA