STRUCTURE OF THE BOVINE FOLLICLE-STIMULATING-HORMONE RECEPTOR COMPLEMENTARY-DNA AND EXPRESSION IN BOVINE-TISSUES

We report the complementary DNA structure obtained by reverse transcri ption and polymerase chain reaction amplification encoding the complet e amino acid sequence for the bovine follicle-stimulating hormone rece ptor (bFSHr). The deduced amino acid sequence for the cDNA revealed a mature polypeptide consisting of 678 amino acids (theoretical weight o f 76.4 kDa) and a 17 amino acid putative leading signal peptide. The r eceptor consists of a large NH2-terminal extracellular membrane domain of 349 aa with 3 potential N-linked glycosylation sites, a transmembr ane domain (264 aa) consisting of 7 putative membrane spanning segment s, and an intracytoplasmic COOH-terminal domain (65 aa). Four potentia l phosphorylation sites were found in the transmembrane domain and the COOH-terminal domain. The amino acid sequence is 97%, 89%, and 88% ho mologous to the ovine, human, and rat FSHr respectively, with complete conservation of the 22 cysteine residues in the whole protein and the 3 N-linked glycosylation sites on the extracellular membrane domain. Northern blot analysis of total mRNA in bovine tissues revealed a majo r mRNA transcript of 2.55 kb for the bFSHr in the ovary without corpus luteum, and in the testis. No expression was found in other tissues a nalyzed. Total RNA from bovine granulosa cells collected from pregnant mare serum gonadotropin (PMSG)-treated prepubertal heifers showed 2 m ajor mRNA transcripts of 6.8 and 2.55 kb, and 3 minor transcripts of 3 .8, 3.3, and 1.6 kb. Bovine granulosa cells cultured with porcine FSH (0, 2, 10 ng/ml) for 4 days showed a decrease in the steady state leve l of the FSHr mRNA. This decrease was shown to be independent of the s ize of the transcript. Therefore, expression of the bovine FSHr by bov ine granulosa cells is downregulated at the message level when exposed to constant concentrations of FSH. (C) 1994 Wiley-Liss, Inc.