The porcine follitropin receptor: cDNA cloning, functional expression and chromosomal localization of the gene.

The porcine follitropin receptor-encoding cDNA (pFSHR) was cloned using reverse transcription-polymerase chain reaction (RT-PCR). Total RNA from porcine granulosa cells was used as template. Two overlapping cDNA fragments encoding, respectively, aa 1 to 290 and aa 191 to 694 of the pFSHR were obtained. Taken together, the two fragments represented the whole coding sequence, assuming a comparable length for the FSHR from the porcine, rat and human species. Functionality of the cloned receptor was assessed by expression experiments; COS cells transfected with the pFSHR cDNA exhibited high-affinity specific binding for [125I]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-terminal 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 pFSHR-encoding gene by radioactive in situ hybridization. This gene was found co-localized (as in human) with the porcine lutropin hormone receptor (pLHR)-encoding gene on the q2.2-q2.3 region of pig chromosome 3.