Deletion of deoxyribonucleic acid binding domain of the vitamin D receptor abrogates genomic and nongenomic functions of vitamin D
Deletion of deoxyribonucleic acid binding domain of the vitamin D receptor abrogates genomic and nongenomic functions of vitamin D
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DOI：
10.1210/me.16.7.1524
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发表时间：
2002-07-01
影响因子：
--
通讯作者：
Balling, R
中科院分区：
文献类型：
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作者：
Erben, RG;Soegiarto, DW;Balling, R
维生素D激素1，25-二羟维生素D-3 [1，25-（OH）（2）D-3]是维生素D的生物活性形式，对完整的矿物质代谢至关重要。使用基因靶向，我们试图产生维生素D受体（VDR）空突变小鼠携带报告基因lacZ驱动的内源性VDR启动子。在这里，我们表明，我们的基因靶向突变小鼠表达VDR与完整的激素结合域，但缺乏DNA结合所必需的第一个锌指。lacZ报告基因的表达广泛分布在胚胎发育和出生后。在骨、软骨、肠、肾、皮肤、脑、心脏和甲状旁腺中发现了强lacZ表达。纯合子小鼠是完全缺乏VDR蛋白的小鼠的表型，并表现出生长迟缓、佝偻病、继发性甲状旁腺功能亢进和脱发。高钙、高磷、高乳糖饮食使血钙和血清甲状旁腺素水平正常化，但在正常血钙纯合子突变体中发现了严重的肾钙渗漏。当小鼠用药理剂量的维生素D代谢物处理时，纯合子小鼠的皮肤、骨骼、肠、甲状旁腺和肾脏中不存在反应，表明突变受体无功能，并且维生素D信号传导途径除了通过经典核受体介导的那些以外具有次要的生理重要性。此外，在纯合子小鼠中，成骨细胞对1，25-（OH）（2）D-3的快速非基因组反应被消除，支持经典VDR介导1，25-（OH）（2）D-3的非基因组作用的结论。
The vitamin D hormone 1,25-dihydroxyvitamin D-3 [1,25-(OH)(2)D-3] the biologically active form of vitamin D, is essential for an intact mineral metabolism. Using gene targeting, we sought to generate vitamin D receptor (VDR) null mutant mice carrying the reporter gene lacZ driven by the endogenous VDR promoter. Here we show that our gene-targeted mutant mice express a VDR with an intact hormone binding domain, but lacking the first zinc finger necessary for DNA binding. Expression of the lacZ reporter gene was widely distributed during embryogenesis and postnatally. Strong lacZ expression was found in bones, cartilage, intestine, kidney, skin, brain, heart, and parathyroid glands. Homozygous mice are a phenocopy of mice totally lacking the VDR protein and showed growth retardation, rickets, secondary hyperparathyroidism, and alopecia. Feeding of a diet high in calcium, phosphorus, and lactose normalized blood calcium and serum PTH levels, but revealed a profound renal calcium leak in normocalcemic homozygous mutants. When mice were treated with pharmacological doses of vitamin D metabolites, responses in skin, bone, intestine, parathyroid glands, and kidney were absent in homozygous mice, indicating that the mutant receptor is nonfunctioning and that vitamin D signaling pathways other than those mediated through the classical nuclear receptor are of minor physiological importance. Furthermore, rapid, nongenomic responses to 1,25-(OH)(2)D-3 in osteoblasts were abrogated in homozygous mice, supporting the conclusion that the classical VDR mediates the nongenomic actions of 1,25-(OH)(2)D-3.