FOLLICLE-STIMULATING-HORMONE RECEPTOR MESSENGER-RNA IN THE MOUSE OVARY DURING POSTNATAL-DEVELOPMENT IN THE NORMAL MOUSE AND IN THE ADULT HYPOGONADAL (HPG) MOUSE - STRUCTURE OF ALTERNATE TRANSCRIPTS

The structure of RNA encoding the mouse ovarian follicle-stimulating hormone (FSH) receptor was studied during post-natal development and in the adult hypogonadal(hpg) mouse which lacks circulating gonadotrophins. Using reverse transcription and the polymerase chain reaction (PCR) four major transcripts of the FSH receptor were found in the normal adult ovary. The largest transcript was the expected size from the position of the PCR primers (on exons 1 and 10) and sequencing confirmed that it was derived from FSH receptor mRNA. The three other transcripts were also derived from FSH receptor mRNA but they contained deletions corresponding to one or more complete exons. Each transcript lacked exon 2 while exons 5 and/or 6 were lacking in the smaller species. All four transcripts were present in ovaries of hag mice showing that expression of receptor mRNA and development of alternate splicing are not gonadotrophin-dependent. During development in the mouse full-length FSH receptor transcripts were not detected in the ovary until day 5 although shorter transcripts were present at days 1 and 3. Results confirm that the FSH receptor primary transcript undergoes alternate splicing in the ovary and that the pattern of splicing changes as the ovary develops, probably as a result of follicular development.