| hVDR原核表达及其与重金属镉、 铅的结合活性 |
| 摘要点击 1209 全文点击 730 投稿时间：2009-11-24 修订日期：2010-01-16 |
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| 中文关键词 人维生素D受体；原核表达；重金属；结合效应；镉；铅 骨代谢 |
| 英文关键词 human vitamin D receptor(hVDR) prokaryotic expression heavy metals combining effect cadmium lead bone metabolism |
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| 中文摘要 |
| 人类维生素D受体(hVDR)是重金属影响骨骼代谢的潜在受体通道,但目前没有重金属影响hVDR通道的报道.通过构建含有hVDR的pGEX-4T-1表达质粒,建立了原核表达具生物学活性的hVDR的方法；然后根据核受体与其配体结合后可以与核受体转录激活因子2(Transcriptional intermediary factor 2, TIF2)-细菌碱性磷酸酶(bacterial alkaline phosphatase, BAP)融合蛋白(TIF2-BAP)结合,建立了研究化学物质影响hVDR与核受体转录激活因子结合活性的磷酸对硝基苯酚法.通过该方法研究发现,镉(CdCl2)或铅(PbAc2)均能提高hVDR与TIF2-BAP的非配体依赖性结合.当加入100 μmol/L和1000 μmol/L氯化镉（CdCl2）后,结合活力分别显著上升至对照组的3.95和4.39倍 (p<0.05)；加入100 μmol/L和1000 μmol/L醋酸铅（PbAc2）后,结合活力分别显著上升至对照组的2.29和3.52倍(p<0.05). 这表明镉和铅可能通过干扰hVDR受体通道的正常功能导致骨代谢异常和骨质疏松症的发生. |
| 英文摘要 |
| Human vitamin D receptor (hVDR) is a potential receptor channel for heavy metals to affect bone metabolism, while to date there is no report about the binding activity between heavy metals and hVDR. This study established a prokaryotic expression of hVDR system, by cloned hVDR-LBD into pGEX-4T-1 vector. Then according to the principle that the nuclear receptor binding with its ligand can be combined with nuclear receptor coactivator 2-bacterial alkaline phosphatase fusion protein (TIF2-BAP), we established a method of p-nitrophenylphosphate-alkaline phosphatase to analyse the effects of chemical on the binding activity between hVDR and TIF2-BAP. Using this method, we studied the binding activities between hVDR and TIF2-BAP after exposure of cadmium and lead. The results showed that the binding activities significantly increased to 3.95 and 4.39 times that of the control after exposure of 100 μmol/L and 1000 μmol/L cadmium chloride (CdCl2), and the binding activities significantly increased to 2.29 and 3.52 times that of the control after exposure of 100 μmol/L and 1000 μmol/L lead acetate (PbAc2), respectively. These results indicate that cadmium and lead can mimic the activity of 1,25-(OH)2D3, disrupt the normal function of hVDR receptor channel, which may be the underlying mechanism of abnormal bone metabolism and osteoporosis caused by cadmium and lead. |
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