Cloning and expression of the turtle (Trachemys scripta) immunoglobulin joining (J)-chain cDNA.
The J-chain protein is a M(r) 15000 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 1934 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, M(r) approximately 15000. 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.
Iwata
Arihiro
A
Department of Pathology, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan. iwata-a@dent.nihon-u.ac.jp
Iwase
Takashi
T
Ogura
Yoshitaka
Y
Takahashi
Tomihisa
T
Matsumoto
Naoyuki
N
Yoshida
Toshiyuki
T
Kamei
Nobuhiro
N
Kobayashi
Kunihiko
K
Mestecky
Jiri
J
Moro
Itaru
I
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D015139:Blotting, Southern; D004247:DNA; D019143:Evolution, Molecular; D007144:Immunoglobulin J-Chains / Q000235:genetics*; D007150:Immunohistochemistry; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014426:Turtles / Q000235:genetics* / Q000276:immunology
D007144:Immunoglobulin J-Chains; D004247:DNA