Molecular cloning of canine IL-13 receptor α chain (α1 and α2) cDNAs and detection of corresponding mRNAs in canine tissues

This communication reports the cloning of cDNAs encoding two canine IL-13 receptor α chains (caIL-13Rα1 and caIL-13Rα2). As described for the members of type-I cytokine receptors, both caIL-13Rα1 and caIL-13Rα2 were found to contain the highly conserved motifs, such as cysteine and tryptophan residues in their N-terminal portion and the WSXWS at C-terminus. The isolated caIL-13Rα1 cDNA contains 1547 nucleotides with an open reading frame that encodes 405 amino acid residues. Canine IL-13Rα1 is 82.0 and 69.3% identical to human and mouse IL-13Rα1s, respectively, at the amino acid level. Canine IL-13Rα1 has an almost identical cytoplasmic domain to its human and mouse counterparts. The isolated caIL-13Rα2 cDNA contains 1454 nucleotides and encodes an open reading frame of 386 amino acid residues. Canine IL-13Rα2 is 62.6 and 47.5% identical to its human and mouse counterparts, respectively, at the amino acid level. Using RT-PCR with caIL-13Rα1 and caIL-13Rα2 specific primers, mRNAs of caIL-13Rα1 and caIL-13Rα2 were detected in most dog tissues. In addition, RT-PCR detected caIL-13Rα1 mRNA in one of two canine mastocytoma (C2 but not Br) cell lines and in a canine macrophage-derived cell line (DH82). CaIL-13Rα2 mRNA was detected in all three canine cell lines.