title: The Immunoglobulin G Heavy Chain (IGHG) genes of the Atlantic bottlenose dolphin, Tursiops truncatus.
abstract: Dolphin Immunoglobulin G Heavy Chain (IGHG) sequences were obtained by PCR amplification of cDNA from peripheral blood leukocytes using degenerate primers. Analysis of full-length sequences indicated the presence of two expressed isotypes, IGHG1 and IGHG2 that differ mainly in the hinge region of the molecule. Genomic Southern blot analysis indicated that the IGHG1 and IGHG2 genes are most likely present in single copies. The inferred amino acid sequences show greatest similarity between the dolphin and other closely related artiodactyl species. The genetic structure of the IGHG genes were deduced through genomic PCR and revealed that the hinge regions of both IGHG1 and IGHG2 are encoded by a single exon. The transmembrane region of the dolphin IGHG chain shows similarity to the transmembrane region of other mammalian IGHG chains with a canonical CART motif. This is in contrast to the unusual Ser to Gly substitution previously found in the dolphin IGHM transmembrane region, and the functional significance of this variation for B cell antigen-receptor dimer activation remains unknown.
authors.affiliation: Marine Biomedicine and Environmental Science Center, Medical University of South Carolina, Hollings Marine Laboratories, 331 Ft. Johnson Road, Charleston, SC, 29412, USA. mancia@musc.edu
authors.forename: Annalaura
authors.initials: A
authors.lastname: Mancia
authors.forename: Tracy A
authors.initials: TA
authors.lastname: Romano
authors.forename: Holly A
authors.initials: HA
authors.lastname: Gefroh
authors.forename: Robert W
authors.initials: RW
authors.lastname: Chapman
authors.forename: Darlene L
authors.initials: DL
authors.lastname: Middleton
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Warr
authors.forename: Mats L
authors.initials: ML
authors.lastname: Lundqvist
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D050681:Bottle-Nosed Dolphin / Q000235:genetics*; D018076:DNA, Complementary / Q000737:chemistry; D005091:Exons / Q000235:genetics; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D012313:RNA / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary
chemical_list: D018076:DNA, Complementary; D007143:Immunoglobulin Heavy Chains; D012313:RNA