Cloning and localization of hFP_S: 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 F_2α. Two isoforms, designated FP _A and FP_B, have been previously described. We now report the cloning of a FP receptor mRNA alternative splice variant from human heart and placenta cDNA, named hFP_S. The cDNA encoding hFP_S has a 71bp insert that produces a frame shift resulting in a truncated receptor lacking transmembrane-7 and the intracellular carboxyl tail. This 71bp sequence has been identified as a distinct exon localized in the human FP receptor gene on chromosome one. Northern blot analysis suggests that hFP_S 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.