Mapping, CDNA Cloning and Tissue Expression of the Porcine Thyrotropin-Releasing Hormone Receptor Gene

Abstract

Thyrotropin-releasing hormone receptor (TRHR) is a G-protein-coupled receptor that plays a crucial role in regulating the hypothalamic-pituitary-thyroid axis by conveying the action of the hypothalamic tripeptide TRH, which is the primary central activator of this hormonal cascade. In the present study, the porcine TRHR (pTRHR) gene was localized to chromosome 4 by Radiation hybrid mapping. Quantitative trait loci affecting average backfat thickness, daily gain, and carcass and meat quality traits have been mapped to the region containing this gene. Further, the full-length cDNA of pTRHR was cloned and sequenced. pTRHR contains an open reading frame encoding 398 amino acids and shares 96.2% amino acid identity to human TRHR. Real-time quantitative RT-PCR showed that the mRNA of pTRHR is expressed in a variety of tissues, with high expression in the brain, hypothalamus, pituitary, testis, and fat tissue. The considerable expression level of TRHR mRNA found in fat tissue indicates potential direct action of TRH on lipocyte might exist. Additionally, two alternative spliced transcript variants of pTRHR were also isolated in this study. Our data provided basic molecular information which will be useful for further investigation on pTRHR gene.

Keywords:

• Pig
• Thyrotropin-releasing hormone receptor
• Tissue distribution
• TRHR

We thank Dr. Martine Yerle for providing the hybrid panel. This work has been supported by the National Basic Research Program of China (No. 2006CB102100) and the National High Technology Research and Development Program of China (No. 2007AA10Z158).

Notes

^#Ta: annealing temperature.