The TRERF1 gene encodes Transcriptional Regulating Factor 1, a zinc finger protein with transcription factor activity. Specifically, the TRERF1 protein interacts with CBP/p300 and activates the transcription of the CYP11A1 gene in steroidal tissues by binding to the gene’s promoter region. CYP11A1 encodes a mitochondrial enzyme involved in the first step of the synthesis of all steroid hormones, i.e. the catalysis of cholesterol to pregnenolone. Hence its activation by TRERF1 is an important biological process required for steroid biosynthesis and the maintenance of homeostasis.