In search of regulatory circuits that control the biological activity of vitamin D

Although the cytochrome P450 CYP27B1 plays a critical role in vitamin D biology, the molecular mechanisms involved in regulation of CYP27B1 have remained undefined. A new study has identified a kidney-specific control module distal to the Cyp27b1 gene that mediates the basal activity and hormonal regulation of Cyp27b1. This work provides a novel mechanism indicating differential regulation of Cyp27b1 in renal and nonrenal cells and has implications for vitamin D biology in multiple sclerosis and perhaps other autoimmune diseases as well.