Cloning and expression of the turtle (Trachemys scripta) immunoglobulin joining (J)-chain cDNA

Academic Article

Abstract

  • The J-chain protein is a Mr 15,000 polypeptide associated with polymeric IgA and IgM. The complete cDNA sequences of human, mouse, cow, brushtail possum, chicken and frog J chains have been previously reported, but nothing is known about the cDNA and amino acid sequences of reptilian J chain. Here, we determined a turtle J-chain cDNA sequence by RT-PCR and RACE, and examined J-chain mRNA and protein expression by Northern blotting and immunohistochemistry. This turtle J-chain cDNA was 1,934 bp and had an open reading frame of 477 nucleotides, encoding 159 amino acids. The mature J-chain protein is composed of 137 amino acids, Mr ∼15,000. The deduced amino acid sequence of the turtle J chain was highly homologous to that of human (60%), mouse (61%), cow (60%), rabbit (60%), chicken (69%), brushtail possum (65%), Rana catesbeiana (47%) and Xenopus laevis (58%). Eight cysteine residues were located at the same positions as in these other species, with the exception of X. laevis. PROSITE database analysis indicated the presence of two N-glycosylation sites in turtle, one of which was novel. Northern blot analysis revealed that turtle J-chain mRNA was expressed in lung, stomach, spleen and intestine. In addition, immunohistochemistry showed J-chain-positive plasma cells in the intestine and spleen. These results suggest the presence of a mucosal immune system mainly composed of J-chain-containing Ig in the turtle.
  • Published In

  • Immunogenetics  Journal
  • Digital Object Identifier (doi)

    Author List

  • Iwata A; Iwase T; Ogura Y; Takahashi T; Matsumoto N; Yoshida T; Kamei N; Kobayashi K; Mestecky J; Moro I
  • Start Page

  • 513
  • End Page

  • 519
  • Volume

  • 54
  • Issue

  • 7