CLONING, EXPRESSION, AND ALTERNATIVE SPLICING OF THE RECEPTOR FOR ANTI-MULLERIAN HORMONE

Anti-Mullerian hormone, also called Mullerian-inhibiting substance or factor, is a glycoprotein dimer belonging to the transforming growth f actor-beta superfamily and synthesized by immature Sertoli cells and p ostnatal granulosa cells. Anti-Mullerian hormone plays a key role in s ex differentiation by inducing the regression of Mullerian ducts in th e male fetus. It is also responsible for the stunting and masculinizat ion of fetal ovaries in bovine freemartin fetuses and may be involved in the control of follicular maturation in the postnatal ovary. Using a degenerate probe for a consensus region of the transforming growth f actor-beta receptor superfamily to screen a complementary DNA library from rabbit fetal ovaries, we cloned a complementary DNA coding for a transmembrane serine/threonine kinase, which is expressed around the f etal Mullerian duct, in fetal and adult granulosa cells, and in immatu re Sertoli cells. Two transcripts, generated by alternative splicing o f an exon coding for an N-terminal 61-amino acid domain, are strongly expressed in anti-Mullerian hormone target organs and Sertoli cells. T he longer, 569-amino acid, isoform binds anti-Mullerian hormone when t ransiently expressed in COS cells and is believed to encode its functi onal receptor.