RESUMO
The cDNA clones for five novel isoforms of prostaglandin (PG) F2 alpha receptor (FP) were isolated from the bovine corpus luteal cDNA library. The sequence analysis revealed that each FP isoform, respectively, encodes 325 (alpha), 326 (beta), 339 (gamma), 293 (delta), and 298 (epsilon) amino acid proteins, carrying the specific carboxyl tails (C-tails) caused by alternative mRNA splicing. Depending on the splicing sites, FP isoforms can be classified into two types. The FP-alpha, FP-beta, and FP-gamma belong to the same group (Type I), which has common amino acid sequences with the exception of each specific 4th intracellular C-tail, while FP-delta and FP-epsilon are classified into the second group (Type II), which has a truncated structure lacking transmembrane domain VII and an intracellular C-tail. The RT-PCR analysis indicated that the mRNAs for these isoforms are expressed at the same time with that of FP in the bovine corpus luteum during the estrous cycle and pregnancy.
