Meeting Abstract

P3.98  Saturday, Jan. 5  Identification and Cloning of a Second Glycoprotein Hormone Receptor (TSH-like Receptor) in Sea Lamprey FREAMAT, MIHAEL; SOWER, STACIA A.*; University of New Hampshire, Durham; University of New Hampshire Durham sasower@cisunix.unh.edu

A full-length transcript encoding a functional sea lamprey glycoprotein hormone receptor (lGpH-R II) was cloned from thyroid tissue. Previously, we determined the cDNA sequences of one gonadotropin beta (Sower et al., 2006), and one GTH receptor (Freamat et al., 2006). The cDNA encoding the full sequence of a glycoprotein hormone receptor is highly similar to thyroid hormone receptor homologs. The 2346 bp complete coding sequence (GenBank AY750689) encodes a 782 amino acid residues protein highly similar with vertebrate thyrotropin hormone receptors. Specific features of its protein sequence classify this receptor as an ancestral thyrotropin receptor rather than a gonadotropin receptor. Maximum expression as determined by RT-PCR was found in the thyroid tissue of lamprey but significant mRNA levels were detected also in brain, testes, intestine and skeletal muscle. The gene of lGpH-R II contains 10 exons, similarly with mammalian TSH-R and FSH-R. All introns were found in the putative extracellular domain, the transmembrane and intracellular domains are encoded by a single exon. This finding may support the concept of the thyrotropin receptor divergence predating the differentiation of the gonadotropin receptors (FSH-R and LH-R) in the evolutionary history of vertebrate glycoprotein hormone receptors. Supported by NSF Grant # 0421923 to SAS.