Direct repeat 3-type element lacking the ability to bind to the vitamin D receptor enhances the function of a vitamin D-responsive element.
In a previous study, we identified the element which allows the maximum response to 1,25(OH)2D3 in concert with two vitamin D-responsive elements (VDREs) in the rat 25-hydroxyvitamin D3 24-hydroxylase gene promoter, and designated it an accessory element [Ohyama, Y., Ozono, K., Uchida, M., Yoshimura, M., Shinki, T., Suda, T. and Yamamoto, O. Functional assessment of two vitamin D-responsive elements in the rat 25-hydroxyvitamin D3 24-hydroxylase gene. J. Biol. Chem., 1996, 271, 30381-30385]. The accessory element located adjacent to the proximal VDRE is not capable of binding to the vitamin D receptor (VDR), while its nucleotide sequence resembles the consensus sequence of VDREs, direct repeat 3 (DR3). To clarify the difference between the accessory element and VDREs, the function of the accessory element was compared with that of VDREs. The mutated accessory elements with a single nucleotide substitution showed the capability of binding to the VDR in vitro. However, these mutants still did not act as a VDRE when driven by the heterologous SV40 promoter. The accessory element did not enhance the function of a cAMP-responsive element. The corresponding site of the accessory element in the human 24-hydroxylase is a DR4-type element, and this element did not function as an accessory element. These results indicate that a critical nucleotide sequence is necessary for the binding to the VDR and for mediating the vitamin D effect, and suggest the different regulation between the rat and human 24-hydroxylase gene.
Ozono
K
K
Department of Environmental Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, Izumi, Japan. j61642@center.osaka-u.ac.jp
Yamagata
M
M
Ohyama
Y
Y
Nakajima
S
S
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D002117:Calcitriol / Q000494:pharmacology*; D016384:Consensus Sequence; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics*; D004247:DNA / Q000378:metabolism; D004274:DNA, Recombinant; D006801:Humans; D012516:Osteosarcoma; D017354:Point Mutation; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D051381:Rats; D018167:Receptors, Calcitriol / Q000378:metabolism*; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D047488:Retinoid X Receptors; D013045:Species Specificity; D013250:Steroid Hydroxylases / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics; D014407:Tumor Cells, Cultured; D065668:Vitamin D3 24-Hydroxylase
D004274:DNA, Recombinant; D018167:Receptors, Calcitriol; D018168:Receptors, Retinoic Acid; D047488:Retinoid X Receptors; D014157:Transcription Factors; D015124:8-Bromo Cyclic Adenosine Monophosphate; D004247:DNA; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D065668:Vitamin D3 24-Hydroxylase; D002117:Calcitriol