SRY protein is expressed in ovotestis and streak gonads from human sex-reversal

In mammals, a master gene located on the Y chromosome, the testis-determini ng gene SRY, controls sex determination. SRY protein is expressed in the ge nital ridge before testis determination, and in the testis it is expressed in Sertoli and germ cells. Completely sex-reversed patients are classified as either 46,XX males or 46,XY females. SRY mutations have been described i n only 15% of patients with 46,XY complete or partial gonadal dysgenesis. H owever, although incomplete or partial sex-reversal affects 46,XX true herm aphrodites, 46,XY gonadal dysgenesis, and 46,XX/46,XY mosaicism, only 15% o f the 46,XX true hermaphrodites analyzed have the SRY gene. Here, we demons trate that the SRY protein is expressed in the tubules of streak gonads and rete testis, indicating that the SRY protein is normally expressed early d uring testis determination. Based on these results, we propose that some fa ctors downstream from SRY may be mutated in these 46,XY sex-reversal patien ts. We have also analyzed SRY protein expression in the ovotestis from 46,X X true hermaphrodites and 46,XX/46,XY mosaicism, demonstrating SRY protein expression in both testicular and ovarian portions in these patients. This suggests that the SRY protein does not inhibit ovary development. These res ults confirm that other factors are needed for complete testis development, in particular, these downstream of the SRY protein. Copyright (C) 2001 S. Karger AG, Basel.