THE PORCINE FOLLITROPIN RECEPTOR - CDNA CLONING, FUNCTIONAL EXPRESSION AND CHROMOSOMAL LOCALIZATION OF THE GENE

The porcine follitropin receptor-encoding cDNA (pFSHR) was cloned usin g reverse transcription-polymerase chain reaction (RT-PCR). Total RNA from porcine granulosa cells was used as template. Two overlapping cDN A fragments encoding, respectively, aa 1 to 290 and aa 191 to 694 of t he pFSHR were obtained. Taken together, the two fragments represented the whole coding sequence, assuming a comparable length for the FSHR f rom the porcine, rat and human species. Functionality of the cloned re ceptor was assessed by expression experiments: COS cells transfected w ith the pl;SHR cDNA exhibited high-affinity specific binding for [I-12 5]hFSH and FSH-dependent cAMP production, The primary sequence of the porcine FSHR N-terminal hormone-binding domain showed high percentages of identity with the sequences from ovine, human, and rat origins. A truncated form of the pFSHR cDNA, lacking aa 75 to 124 in the N-termin al domain, was also cloned and sequenced. A PCR-derived cDNA fragment of 1.45 kb was used as gene-specific hybridisation probe to map the pF SHR-encoding gene by radioactive in situ hybridization. This gene was found co-localized (as in human) with the porcine lutropin hormone rec eptor (pLHR)-encoding gene on the q2.2-q2.3 region of pig chromosome 3 .