Cloning of a Functional Vitamin D Receptor from the Lamprey, an Ancient Vertebrate Lacking a Calcified Skeleton and Teeth

Researchers cloned a functional vitamin D receptor (VDR) from the lamprey (Petromyzon marinus), an ancient vertebrate without mineralized tissues or hair. Despite these absences, the lamprey VDR (lampVDR) bound 1,25-dihydroxyvitamin D3 with high affinity and activated a reporter gene linked to a vitamin D-responsive element from the human CYP3A4 gene in mammalian cells. However, lampVDR showed little or no activity with other vitamin D responsive elements. Phylogenetic analysis indicated that lampVDR is a basal member of the VDR group, closely related to pregnane X receptors and constitutive androstane receptors, suggesting its role in xenobiotic detoxification in lampreys.