Metallothionein gene expression in rats: tissue-specific regulation by dietary copper and zinc.
Metallothionein gene expression in rats: tissue-specific regulation by dietary copper and zinc.
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DOI：
10.1093/jn/118.2.222
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发表时间：
1988-02
期刊：
影响因子：
--
通讯作者：
T. Blalock;M. Dunn;R. Cousins
中科院分区：
文献类型：
--
作者：
T. Blalock;M. Dunn;R. Cousins
采用3 × 3析因设计研究了锌和铜对大鼠肝、肾、肠和脑金属硫蛋白基因表达的调节作用。分别饲喂含锌5、30、180 mg/kg和铜1、6、36 mg/kg的纯饲粮2 wk。血清中铜和锌的浓度较低，在最低摄入量的金属比在正常或补充水平。肾脏金属硫蛋白水平与膳食锌成正比，5 mg Zn/kg组比最高锌摄入量组低50%。通过与代表金属硫蛋白基因末端5'序列的32 P标记的寡核苷酸DNA探针的斑点印迹杂交来测量金属硫蛋白mRNA。在肾脏中，随着膳食锌的增加，每个细胞的金属硫蛋白mRNA分子的数量增加了4到5倍（从4到29个分子/细胞）。对金属硫蛋白mRNA的影响不太明显，观察到在响应饮食铜。在最低的铜摄入量和最高的锌摄入量的肠道金属硫蛋白mRNA的7倍以上的任何其他组。肝脏和大脑没有明显的反应，以饮食水平的铜和锌的喂养。色谱分析表明，肾脏金属硫蛋白中铜、锌含量与饲粮水平直接相关。在肾脏中，金属硫蛋白-1和-2基因均表达。
Regulation of metallothionein gene expression by dietary zinc and copper was examined in rat liver, kidney, intestine and brain using a 3 X 3 factorial design. Purified diets containing 5, 30 and 180 mg Zn/kg and 1, 6 and 36 mg Cu/kg were fed for 2 wk. Serum concentrations of copper and zinc were lower at the lowest intakes of either metal than at normal or supplemental levels. Kidney metallothionein levels were proportional to dietary zinc, being 50% less in the 5 mg Zn/kg group than in those fed the highest zinc intake. Metallothionein mRNA was measured by dot blot hybridization to a 32P-labeled oligonucleotide DNA probe representing the terminal 5' sequence of the metallothionein gene. In kidney the number of metallothionein mRNA molecules per cell increased four- to five-fold (from 4 to 29 molecules per cell) with increasing dietary zinc. A less pronounced effect on metallothionein mRNA was observed in response to dietary copper. At the lowest copper intake level and highest intake of zinc intestinal metallothionein mRNA was sevenfold greater than in any other group. Liver and brain did not respond appreciably to the dietary levels of copper and zinc that were fed. Chromatography showed that copper and zinc content of renal metallothionein was directly related to the dietary levels fed. In kidney, both metallothionein-1 and -2 genes were expressed.