Transcriptional regulation of CYP11A1.

Steroid hormones are important physiological regulators that control our glucose and salt balance, as well as sexual characteristics. The synthesis of steroid hormones is under tight control; disturbed secretion of steroids often leads to diseases. The mechanism controlling the secretion of steroids, namely steroidogenesis, has been the focus of intensive studies. CYP11A1 controls the first and rate-limiting step of steroid biosynthesis. It is expressed in the adrenal cortex and gonads, under the control of pituitary hormones, through the cAMP-signaling pathway. The promoter of the CYP11A1 gene contains sequences that bind to transcription factor SF-1, which plays an important role in the tissue-specific and hormonally regulated expression of steroidogenic genes. Detailed transcriptional analysis documents the importance of SF-1 in activating CYP11A1 in vitro and in vivo. Other factors like c-Jun are also involved. The assembly of various transcription factors forming protein-DNA complexes appears to be the key step in CYP11A1 transcription.