Cloning and localization of hFPS: a six-transmembrane mRNA splice variant of the human FP prostanoid receptor

FP prostanoid receptors are G-protein coupled receptors that mediate the actions of prostaglandin F2α. Two isoforms, designated FPA and FPB, have been previously described. We now report the cloning of a FP receptor mRNA alternative splice variant from human heart and placenta cDNA, named hFPS. The cDNA encoding hFPS has a 71 bp insert that produces a frame shift resulting in a truncated receptor lacking transmembrane-7 and the intracellular carboxyl tail. This 71 bp sequence has been identified as a distinct exon localized in the human FP receptor gene on chromosome one. Northern blot analysis suggests that hFPS is expressed in skeletal muscle as well as human heart and placenta. Immunohistochemical microscopy showed positive immunoreactivity on vascular endothelial, trophoblast, and decidual cells from human placenta. hFPs represents the first confirmed alternative splice variant of the human FP prostanoid receptor gene, however, its function is presently unknown.