Cloning and expression of a putative common cytokine receptor gamma chain (gamma C) gene in rainbow trout (Oncorhynchus mykiss)

A full length cDNA of a putative common cytokine receptor gamma chain (gamm aC) gene of rainbow trout (Oncorhynchus mykiss) has been cloned and sequenc ed. The contiguous cDNA contained 2291 nucleotides, consisting of an ORF of 1029 bp, with a 72 bp 5' UTR and a 1190 bp 3' UTR. The coding region showe d 44-46% identity to mammalian gammaC genes. The ORF translated into a 343 amino acid protein, with some 28-30% amino acid identity to the coding regi on of mammalian sequences. A predicted signal peptide and transmembrane dom ain were identified, giving a 206 amino acid extracellular domain and a 98 amino acid intracellular domain in the trout molecule. Five potential glyco sylation sites were present in the extracellular domain, as were six conser ved cysteine residues and the W-S-X-W-S motif typical of haemopoietin recep tors. One of the most interesting differences between the trout and mammali an sequences was the lack of tyrosines in the trout intracellular domain. R T-PCR studies revealed a wide tissue distribution of gammaC expression, wit h detectable transcript in blood, spleen, gill, kidney, brain and liver. Lo w levels of gammaC transcript were detectable in unstimulated macrophage cu ltures and expression was increased by stimulation of the cells with recomb inant trout interleukin-1 beta (IL-1 beta) or LPS. Similarly, in the RTG ce ll line which exhibited even lower level constitutive expression, stimulati on with IL-1 beta increased gammaC transcript levels but LPS had no effect. (C) 2001 Academic Press.