title: Cloning and characterization of the vitamin D receptor from Xenopus laevis.
abstract: The Vitamin D receptor (VDR), a member of the nuclear receptor superfamily, mediates the effects of 1,25-dihydroxyvitamin D3 on mineral ion homeostasis. Although the mammalian and avian VDRs have been extensively studied, little is known about the VDR in lower vertebrate species. To address this, we have isolated the Xenopus laevis VDR (xVDR) complementary DNA. Overall, the xVDR shares 79%, 73%, 73%, and 75% identity at the amino acid level with the chicken, mouse, rat, and human VDRs, respectively. The amino acid residues and subdomains important for DNA binding, hormone binding, dimerization, and transactivation are mostly conserved among all VDR species. The xVDR polypeptide can heterodimerize with the mouse retinoid X receptor alpha, bind to the rat osteocalcin vitamin D response element (VDRE), and induce vitamin D-dependent transactivation in transfected mammalian cells. Northern analysis reveals two xVDR messenger RNA species of 2.2 kb and 1.8 kb in stage 60 Xenopus tissues. In the adult, xVDR expression is detected in many tissues including kidney, intestine, skin, and bone. During Xenopus development, xVDR messenger RNA first appears at developmental stage 13 (pre-neurulation), increasing to maximum at stages 57-61 (metamorphosis). Our data demonstrate that, in Xenopus, VDR expression is developmentally regulated and that the vitamin D endocrine system is highly conserved during evolution.
authors.affiliation: Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston 02114, USA.
authors.forename: Y C
authors.initials: YC
authors.lastname: Li
authors.forename: C
authors.initials: C
authors.lastname: Bergwitz
authors.forename: H
authors.initials: H
authors.lastname: Jüppner
authors.forename: M B
authors.initials: MB
authors.lastname: Demay
mesh_terms: D000375:Aging; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001842:Bone and Bones / Q000378:metabolism; D002645:Chickens; D003001:Cloning, Molecular; D019281:Dimerization; D004625:Embryo, Nonmammalian / Q000502:physiology; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007421:Intestine, Small / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009928:Organ Specificity; D016133:Polymerase Chain Reaction; D051381:Rats; D018167:Receptors, Calcitriol / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D018168:Receptors, Retinoic Acid / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D000072482:Retinoic Acid Receptor alpha; D017386:Sequence Homology, Amino Acid; D012867:Skin / Q000378:metabolism; D013045:Species Specificity; D014982:Xenopus laevis
chemical_list: C000607071:RARA protein, human; C000607072:Rara protein, mouse; C000607073:Rara protein, rat; D018167:Receptors, Calcitriol; D018168:Receptors, Retinoic Acid; D011994:Recombinant Proteins; D000072482:Retinoic Acid Receptor alpha