ABNORMAL BINDING OF VITAMIN-D RECEPTORS TO DEOXYRIBONUCLEIC-ACID IN A KINDRED WITH VITAMIN D-DEPENDENT RICKETS, TYPE-II
ABNORMAL BINDING OF VITAMIN-D RECEPTORS TO DEOXYRIBONUCLEIC-ACID IN A KINDRED WITH VITAMIN D-DEPENDENT RICKETS, TYPE-II
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DOI：
10.1210/jcem-68-2-263
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发表时间：
1989-02-01
影响因子：
5.8
通讯作者：
FELDMAN, D
中科院分区：
文献类型：
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作者：
MALLOY, PJ;HOCHBERG, Z;FELDMAN, D
维生素D依赖性佝偻病II型是一种遗传性疾病，由靶器官对1，25-二羟基维生素D3 [1，25-（OH）2D 3]的作用产生抗性引起。我们在这里描述了一个家庭（指定G）与缺陷的DNA结合结构域的1，25-（OH）2D受体（VDR）表现为正常的类固醇结合和降低VDR的亲和力的DNA。表型正常的父母是杂合子，表达正常和缺陷形式的VDR。该家族的患病儿童有早发性佝偻病、脱发、低钙血症和血清1，25-（OH）2D 3水平升高。患病儿童（G1和G2）以及父母（G3和G4）的培养的皮肤成纤维细胞的VDR正常地结合[3 H] 1，25-（OH）2D 3（Kd = 2-3 × 10 - 6）。10-11 mol/L;最大结合位点数= 20-40 fmol/mg蛋白质）。G_1和G_2的细胞对1，25-（OH）_2D_3的作用有抗性，而G_3和G_4的细胞反应正常。使用抗VDR单克隆抗体9A 7进行的Western印迹分析显示，来自患病儿童（G1和G2）及其父母（G3和G4）的成纤维细胞的高渗提取物具有48 K的免疫反应条带，与正常细胞中VDR的大小相同。在较低的盐浓度（0.1 mol/L）下，G1和G2的VDR从DNA-纤维素柱上洗脱为单峰，表明对DNA的亲和力明显降低。来自G3和G4的成纤维细胞VDR各自从DNA-纤维素柱洗脱为两个峰，正常峰（0.2mol/L）和在G1和G2中发现的异常峰（0.1mol/L）。0.1和0.2 mol/L KCl峰级分的蛋白质印迹分析也证实，VDR仅存在于0.1 mol/L级分中，而不存在于G1的0.2 mol/L级分中。然而，VDR存在于来自G3的两个级分中。总之，这种维生素D依赖性佝偻病，II型，亲属在VDR的DNA结合域有缺陷。父母是表型正常的，并表达正常和有缺陷的VDR等位基因，如DNA-纤维素层析和蛋白质印迹分析所示。受影响的儿童对1，25-（OH）2D 3作用有抵抗力，并且是VDR缺陷的纯合型。
Vitamin D-dependent rickets, type II, is a hereditary disease that results from target organ resistance to the action of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3]. We describe here a family (designated G) with a defect in the DNA-binding domain of the 1,25-(OH)2D receptor (VDR) manifested by normal steroid binding and decreased VDR affinity for DNA. The phenotypically normal parents are heterozygous, expressing both normal and defective forms of VDR. The affected children in this family had early-onset rickets, alopecia, hypocalcemia, and elevated serum 1,25-(OH)2D3 levels. The VDR of cultured skin fibroblast of the affected children (G1 and G2) as well as the parents (G3 and G4) bound [3H]1,25-(OH)2D3 normally (Kd = 2-3 .times. 10-11 mol/L; maximal number of binding sites = 20-40 fmol/mg protein). The cells from G1 and G2 were resistent to 1,25-(OH)2D3 action, as measured by induction of 24-hydroxylase activity, while the cells from G3 and G4 responded normally. Western blot analysis using the anti-VDR monoclonal antibody 9A7 showed that hypertonic extracts of fibroblasts from both affected children (G1 and G2) and their parents (G3 and G4) had immunoreactive bands of 48K, identical to the size of the VDR in normal cells. The VDR from G1 and G2 eluted as a single peak from DNA-cellulose columns at a lower salt concentration (0.1 mol/L) than that from normal subjects (0.2 mol/L), indicating an apparent decreased affinity for DNA. Fibroblast VDR from G3 and G4 each eluted from DNA-cellulose columns as two peaks, the normal peak (0.2 mol/L) and the abnormal peak (0.1 mol/L), which was found in G1 and G2. Western blot analysis of the 0.1 and 0.2 mol/L KCl peak fractions also confirmed that VDR was present in only the 0.1 mol/L fraction and not the 0.2 mol/L fraction from G1. However, VDR was present in both fractions from G3. In summary, this vitamin D-dependent rickets, type II, kindred has a defect in the DNA-binding domain of VDR. The parents are phenotypically normal and express both the normal and defective VDR alleles, as demonstrated by both DNA-cellulose chromatography and Western blot analysis. The affected children are resistant to 1,25-(OH)2D3 action and are homozygous for the defective VDR.