Molecular cloning, sequencing and functional expression of porcine thyrotropin (TSH) receptor cDNA1).

We directly sequenced PCR fragments amplified from a porcine thyroid cDNA library with various synthetic primers based on the nucleotide sequence of bovine thyrotropin receptor (bTSHR) cDNA. A nucleotide sequence of 2410 bp was determined and its deduced amino acid sequence contained an open reading frame coding 764 amino acids, which showed 91.8% and 89.5% similarity to bTSHR and human TSH receptor, respectively. A hydrophobicity plot of the porcine protein suggested that it had a putative signal peptide and seven transmembrane domains. Chinese hamster ovary cells stably transfected with the cDNA could be specifically bound to bovine TSH (bTSH) and increased the intracellular cAMP level in response to bTSH and Graves' disease patients' sera stimulation.