Basic helix-loop-helix transcription factor Tcf21 is downstream target of male sex-determining gene SRY

The cascade of molecular events involved in mammalian sex determination has been shown to involve the SRY gene, but specific downstream events have eluded researchers for decades. The current study identifies one of the first direct downstream targets of the male sex-determining factor SRY as the basic-helix-loop-helix (bHLH) transcription factor TCF21. SRY was found to directly associate with the Tcf21 promoter SRY/SOX9 response element both in vitro and in vivo during male sex determination. TCF21 was found to promote an in vitro sex reversal of embryonic ovarian cells to promote precursor Sertoli cell differentiation. Therefore, SRY acts directly on the Tcf21 promoter to, in part, initiate a cascade of events associated with Sertoli cell differentiation and embryonic testis development.

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Bhandari RK, Sadler-Riggleman I, Clement TM, Skinner MK