title: [Prokaryotic expression of human vitamin D receptor (hVDR) and its binding activities to Cd and Pb].
abstract: 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 micromol/L and 1 000 micromol/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 micromol/L and 1 000 micromol/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.
authors.affiliation: School of Food Science and Technology, Henan University of Technology, Zhengzhou 450052, China. jiaojian1111@yahoo.com.cn
authors.forename: Jian
authors.initials: J
authors.lastname: Jiao
authors.forename: Zhao-Bin
authors.initials: ZB
authors.lastname: Zhang
authors.forename: Jian-Ying
authors.initials: JY
authors.lastname: Hu
authors.forename: Jin-Shui
authors.initials: JS
authors.lastname: Wang
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D002104:Cadmium / Q000378:metabolism* / Q000633:toxicity; D003001:Cloning, Molecular; D004785:Environmental Pollutants / Q000378:metabolism* / Q000633:toxicity; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D007854:Lead / Q000378:metabolism* / Q000633:toxicity; D051958:Nuclear Receptor Coactivator 2 / Q000378:metabolism; D010024:Osteoporosis / Q000139:chemically induced*; D018167:Receptors, Calcitriol / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics
chemical_list: D004785:Environmental Pollutants; C498001:NCOA2 protein, human; D051958:Nuclear Receptor Coactivator 2; D018167:Receptors, Calcitriol; D011993:Recombinant Fusion Proteins; D002104:Cadmium; D007854:Lead; D000469:Alkaline Phosphatase