Brenza H L, Kimmel-Jehan C, Jehan F, Shinki T, Wakino S, Anazawa H, Suda T, DeLuca H F
Department of Biochemistry, University of Wisconsin-Madison, 420 Henry Mall, Madison, WI 53706, USA.
Proc Natl Acad Sci U S A. 1998 Feb 17;95(4):1387-91. doi: 10.1073/pnas.95.4.1387.
The DNA flanking the 5' sequence of the mouse 1alpha-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 D3-1alpha-hydroxylase by acting on the promoter of the 1alpha-hydroxylase gene.
小鼠1α-羟化酶基因5'序列侧翼的DNA已被克隆和测序。在-30 bp处发现了一个TATA盒,在-79 bp处发现了一个CCAAT盒。通过将荧光素酶报告基因构建体转染到改良的猪肾细胞系AOK-B50中,证明了该基因的启动子活性。甲状旁腺激素可使这种由启动子指导的荧光素酶合成增加17倍,而福斯可林可使其增加3倍。甲状旁腺激素的作用具有浓度依赖性。1,25-二羟基维生素D3不抑制基础启动子活性,对甲状旁腺激素驱动的荧光素酶报告活性有轻微抑制作用。该启动子有三个潜在的cAMP反应元件位点,两个完美的和一个不完美的AP-1位点,未检测到DR-3。这些结果表明,甲状旁腺激素通过作用于1α-羟化酶基因的启动子来刺激25-羟基维生素D3-1α-羟化酶。