Two vitamin D response elements function in the rat 1,25-dihydroxyvitamin D 24-hydroxylase promoter.
The interaction between the two vitamin D response elements (DRE) located at -154 to -134 base pairs (bp) and -262 to -238 bp from the transcription initiation site has been studied using reporter gene assays and binding assays by electrophoretic gel shift measurements. 3 half-sites separated by 3 bp were found necessary for transactivation by the -154 to -125 DRE, while 2 half-sites separated by 3 bp were needed for the DRE at -262 to -238 to function. However, the two DREs together provided maximal activity. The 93-bp fragment separating the two DREs was not required and could be deleted. The most effective binding by receptor was found with the two complete DREs (dissociation constant (Kd) = 13.7 pM), although each DRE bound to the receptor and nuclear accessory factor with about 5 nM Kd. The two DREs (a total of 5 half-sites) apparently account for most if not all of the transactivation of the rat 24-hydroxylase by 1,25-dihydroxyvitamin D3. This system represents the most powerful of the DREs reported to date.
Zierold
C
C
Department of Biochemistry, University of Wisconsin-Madison 53706.
Darwish
H M
HM
DeLuca
H F
HF
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System; D007413:Intestinal Mucosa / Q000378:metabolism; D007668:Kidney; D007700:Kinetics; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D011401:Promoter Regions, Genetic; D051381:Rats; D018167:Receptors, Calcitriol / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis; D013250:Steroid Hydroxylases / Q000096:biosynthesis* / Q000235:genetics*; D013552:Swine; D014158:Transcription, Genetic; D014162:Transfection; D065668:Vitamin D3 24-Hydroxylase
D009838:Oligodeoxyribonucleotides; D018167:Receptors, Calcitriol; D011994:Recombinant Proteins; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D065668:Vitamin D3 24-Hydroxylase; D015500:Chloramphenicol O-Acetyltransferase