ZFY IS TRANSCRIBED IN THE NORMAL MOUSE EPIDIDYMIS AND IN THE XXSXR (SEX REVERSED) TESTIS

The presence of the mutation Sex reversed (Sxr), a copy of a Y-chromos omal segment that gets transferred to an X chromosome, causes the resu lting XXSxr mice to develop as apparent males. However, several featur es of male sexual development are abnormal in these animals. The teste s are small and aspermatogenic, and the epididymides lack the initial segment. Testes and epididymides show abnormalities of extracellular m atrix. In this study we examined transcription of the conserved Y chro mosomal gene Zfy, which has an X-chromosomal homologue (Zfx). Northern blotting showed Zfy to be expressed in the testes of XXSxr animals, e xcept for those that carry the coat-marker gene Tabby (Ta), despite th e lack of germ cells in XXSxr mice. Reverse transcription polymerase c hain reaction (RT-PCR) studies detected Zfy in mRNA in testes even whe n Ta was present. RT-PCR also demonstrated Zfy transcription in epidid ymides of normal males, though not in XXSxr mice. Previous authors rep orted an absence of Zfy transcription in XXSxr testes; Zfy transcripti on in normal testes has been ascribed to germ cells. Our observation i ndicates that this idea requires re-evaluation. The occurrence of Zfy transcription in the normal epididymis is similarly a novel finding th at may help explain those aspects of epididymal development that occur in the absence of androgen. (C) 1994 Wiley-Liss, inc.