title: Chromate Reductase YieF from Escherichia coli Enhances Hexavalent Chromium Resistance of Human HepG2 Cells.
abstract: Hexavalent chromium (Cr(VI)) is a serious environmental pollutant and human toxicant. Mammalian cells are very sensitive to chromate as they lack efficient chromate detoxifying strategy, e.g., chromate-reducing genes that are widely present in prokaryotes. To test whether introduction of prokaryotic chromate-reducing gene into mammalian cells could render higher chromate resistance, an Escherichia coli chromate-reducing gene yieF was transfected into human HepG2 cells. The expression of yieF was measured in stably transfected cells HepG2-YieF by quantitative RT-PCR and found up-regulated by 3.89-fold upon Cr(VI) induction. In chromate-reducing ability test, HepG2-YieF cells that harbored the reductase showed significantly higher reducing ability of Cr(VI) than HepG2 control cells. This result was further supported by the evidence of increased Cr(VI)-removing ability of crude cell extract of HepG2-YieF. Moreover, HepG2-YieF demonstrated 10% higher viability and decreased expression of GSH synthesizing enzymes under Cr(VI) stress. Subcellular localization of YieF was determined by tracing GFP-YieF fusion protein that was detected in both nucleus and cytoplasm by laser confocal microscopy. Altogether, this study successfully demonstrated that the expression of a prokaryotic Cr(VI)-reducing gene yieF endowed mammalian cell HepG2 with enhanced chromate resistance, which brought new insight of Cr(VI) detoxification in mammalian cells.
authors.affiliation: Department of Developmental Biology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. kathyliu0505@gmail.com.
authors.forename: Xuan
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Developmental Biology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. wugf12@lzu.edu.cn.
authors.forename: Gaofeng
authors.initials: G
authors.lastname: Wu
authors.affiliation: Department of Developmental Biology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. zhangyanli12@lzu.edu.cn.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Developmental Biology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. wudan11@lzu.edu.cn.
authors.forename: Dan
authors.initials: D
authors.lastname: Wu
authors.affiliation: Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. xkli@lzu.edu.cn.
authors.forename: Xiangkai
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Developmental Biology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. liupu@lzu.edu.cn.
authors.forename: Pu
authors.initials: P
authors.lastname: Liu
mesh_terms: D002274:Carcinogens, Environmental / Q000633:toxicity*; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival; D002857:Chromium / Q000633:toxicity*; D003593:Cytoplasm / Q000378:metabolism; D004351:Drug Resistance; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D014162:Transfection
chemical_list: D002274:Carcinogens, Environmental; D029968:Escherichia coli Proteins; D002857:Chromium; C074702:chromium hexavalent ion; D010088:Oxidoreductases; C508489:YieF protein, E coli
keywords: Cr(VI) resistance; HepG2; chromate reduction; transfection; yieF