The cDNA cloning and transient expression of a chicken gene encoding a follicle-stimulating hormone receptor

A clone, pcFSHR, containing a 3.1-kb insert was isolated from a cDNA library of chicken ovarian follicles by screening with an RT-PCR-generated cDNA probe for a putative N-terminal half-region of chicken FSH-R. The deduced amino acid sequence of pcFSHR exhibits about 84% identity to those of mammalian FSH-R and about 70% to those of mammalian LH-CG-R. Northern blot analysis for total RNA preparations from several chicken tissues revealed that transcripts detected with pcFSHR were present exclusively in ovary and testis. In a chicken ovary, the transcripts were detected in granulosa but not in theca cells. A radioligand receptor assay for the human 293 cells transfected with an expression vector containing the insert of pcFSHR demonstrated the production of a receptor which showed about 10-fold higher affinity for chicken FSH than for chicken LH. The affinity for chicken FSH was significantly higher than for human FSH. In consistency with the ligand specificity of the receptor, a significantly higher level of intracellular accumulation of cAMP was detected when the transfected cells were treated with chicken FSH than with chicken LH. From these results, we conclude that pcFSHR is a cDNA clone for the chicken FSH-R.