title: Genes of the constant regions of functional immunoglobulin heavy chain of Japanese flounder, Paralichthys olivaceus.
abstract: IgM and IgD genes of the Japanese flounder were cloned and characterized from a genomic bacterial artificial chromosome (BAC) library. The micro gene contained four constant region exons (Cmi1-Cmi4), and two transmembrane exons (miTM1 and miTM2), which conforms to the organizational pattern of all other vertebrate micro-chain genes examined so far. In the same BAC clone, the delta gene, which is homologous to the IgD gene in mammals and teleost fish, was found immediately (0.9 kb) downstream of the IgM gene. This gene encoded seven exons (Cdelta1-Cdelta7) and two deltaTM exons (deltaTM1 and deltaTM2) and had no duplication of Cdelta1-Cdelta2, as found in Atlantic cod, or Cdelta2-Cdelta3-Cdelta4, as found in Atlantic salmon and channel catfish. Phylogenetic and sequence analyses strongly suggest that teleost delta is more closely related to non-IgM isotypes than IgM isotypes. The heavy chain (IgH) locus of Japanese flounder, which encodes microm, micros and deltam, was found to be fully functional.
authors.affiliation: Laboratory of Genome Science, Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Konan 4-5-7, Minato 108-8477, Tokyo, Japan.
authors.forename: Prapansak
authors.initials: P
authors.lastname: Srisapoome
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Ohira
authors.forename: Ikuo
authors.initials: I
authors.lastname: Hirono
authors.forename: Takashi
authors.initials: T
authors.lastname: Aoki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern / Q000662:veterinary; D022202:Chromosomes, Artificial, Bacterial; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry*; D005432:Flounder / Q000235:genetics / Q000276:immunology*; D015870:Gene Expression / Q000235:genetics; D007127:Immunoglobulin Constant Regions / Q000235:genetics*; D007072:Immunoglobulin D / Q000737:chemistry / Q000235:genetics*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007075:Immunoglobulin M / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny
chemical_list: D018076:DNA, Complementary; D007127:Immunoglobulin Constant Regions; D007072:Immunoglobulin D; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M