SITES OF TRANSCRIPTION OF THE MULLERIAN-INHIBITING SUBSTANCE GENE IN MOUSE TESTIS

We have examined the transcription of Mullerian inhibiting substance ( MIS) in testis by the sensitive technique of reverse transcription pol ymerase chain reaction (RTPCR). A developmental study of testis by thi s nonquantitative technique showed expression at all postnatal stages, including adults while liver and kidney provided negative controls. C ell separation studies indicated that highly purified interstitial cel ls, as well as less homogeneous Sertoli cell-enriched and germ cell-en riched fractions, contained RNA for MIS. The transcription of MIS in a n interstitial cell type was confirmed by finding MIS mRNA in purified Leydig cells. Inasmuch as the germ cell-enriched fraction contains so me Sertoli cells, and XX,Sxr(a) and XX,Sxr(b) which have germ cell-dep leted testes, contain MIS mRNA, a Sertoli cell source remains likely f or the seminiferous tubule compartment.