Evolutionary history and functional characterization of the amphibian xenosensor CAR.

ABSTRACT: The xenosensing constitutive androstane receptor (CAR) is widely considered to have arisen in early mammals via duplication of the pregnane X receptor (PXR). We report that CAR emerged together with PXR and the vitamin D receptor from an ancestral NR1I gene already in early vertebrates, as a result of whole-genome duplications. CAR genes were subsequently lost from the fish lineage, but they are conserved in all taxa of land vertebrates. This contrasts with PXR, which is found in most fish species, whereas it is lost from Sauropsida (reptiles and birds) and plays a role unrelated to xenosensing in Xenopus. This role is fulfilled in Xenopus by CAR, which exhibits low basal activity and pronounced responsiveness to activators such as drugs and steroids, altogether resembling mammalian PXR. T

SUBMITTER: Mathas M 

PROVIDER: S-EPMC5417167 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature