SREBF1A (SREBP1A) and SREBF2 (SREBP2) bind the promoter of the 7-Dehydrocholesterol Reductase (DHCR) gene and enhance transcription (Sakakura et al. 2001, Reed et al. 2008, reviewed in Horton et al. 2002). The DHCR7 gene is transcribed to yield mRNA and the mRNA is translated to yield protein.
Cholesta-5,7,24-trien-3beta-ol and NADPH + H+ react to form desmosterol and NADP+. This reaction is catalyzed by DHCR7, associated with the endoplasmic reticulum membrane. The biochemical details of the reaction are inferred from those of the reaction catalyzed by the well-studied rat enzyme (Bae et al. 1999).