Parathyroid hormone activation of the 25-hydroxyvitamin D3-1α-hydroxylase gene promoter

Parathyroid hormone activation of the 25-hydroxyvitamin D₃-1α-hydroxylase gene promoter

^*Department of Biochemistry, University of Wisconsin–Madison, 420 Henry Mall, Madison, WI 53706; ^†Department of Biochemistry, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142, Japan; ^‡Department of Internal Medicine, University of Keio, Shinanomachi, Shinjuku-ku, Tokyo 160, Japan; and ^§Tokyo Research Laboratories, Kyowa Hakko Kogyo Company, Ltd., Asahimachi, Machida, Tokyo 194, Japan

Contributed by Hector F. DeLuca

Abstract

The DNA flanking the 5′ sequence of the mouse 1α-hydroxylase gene has been cloned and sequenced. A TATA box has been located at −30 bp and aCCAAT box has been located at −79 bp. The gene’s promoter activity has been demonstrated by using a luciferase reporter gene construct transfected into a modified pig kidney cell line, AOK-B50. Parathyroid hormone stimulates this promoter-directed synthesis of luciferase by 17-fold, whereas forskolin stimulates it by 3-fold. The action of parathyroid hormone is concentration-dependent. 1,25-Dihydroxyvitamin D₃ does not suppress basal promoter activity and marginally suppresses parathyroid hormone-driven luciferase reporter activity. The promoter has three potential cAMP-responsive element sites, and two perfect and one imperfect AP-1 sites, while no DR-3 was detected. These results indicate that parathyroid hormone stimulates 25-hydroxyvitamin D₃-1α-hydroxylase by acting on the promoter of the 1α-hydroxylase gene.

Footnotes

↵ ¶ To whom correspondence should be addressed. e-mail: deluca{at}biochem.wisc.edu.
Data deposition: The sequence reported in this paper has been deposited in the GenBank database (accession no. AF041256).
ABBREVIATIONS:

1,

25-(OH)2D3, 1,25-dihydroxyvitamin D3;

VDR,

vitamin D receptor;

VDDRI,

vitamin D dependency rickets type I;

PTH,

parathyroid hormone;

cAMP,

cyclic AMP;

CRE,

cAMP-responsive element;

CREB,

CRE-binding protein;

PKA,

protein kinase A