De Vit M J, Waddle J A, Johnston M
Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Mol Biol Cell. 1997 Aug;8(8):1603-18. doi: 10.1091/mbc.8.8.1603.
Glucose represses the transcription of many genes in bakers yeast (Saccharomyces cerevisiae). Mig1 is a Cys2-His2 zinc finger protein that mediates glucose repression of several genes by binding to their promoters and recruiting the general repression complex Ssn6-Tup1. We have found that the subcellular localization of Mig1 is regulated by glucose. Mig1 is imported into the nucleus within minutes after the addition of glucose and is just as rapidly transported back to the cytoplasm when glucose is removed. This regulated nuclear localization requires components of the glucose repression signal transduction pathway. An internal region of the protein separate from the DNA binding and repression domains is necessary and sufficient for glucose-regulated nuclear import and export. Changes in the phosphorylation status of Mig1 are coincident with the changes in its localization, suggesting a possible regulatory role for phosphorylation. Our results suggest that a glucose-regulated nuclear import and/or export mechanism controls the activity of Mig1.
葡萄糖可抑制面包酵母（酿酒酵母）中许多基因的转录。Mig1是一种Cys2-His2锌指蛋白，它通过与几个基因的启动子结合并募集通用抑制复合物Ssn6-Tup1来介导葡萄糖对这些基因的抑制作用。我们发现Mig1的亚细胞定位受葡萄糖调控。添加葡萄糖后几分钟内，Mig1就会被导入细胞核，而当葡萄糖被去除时，它又会同样迅速地运回细胞质。这种受调控的核定位需要葡萄糖抑制信号转导途径的组分。该蛋白中与DNA结合和抑制结构域分开的一个内部区域对于葡萄糖调控的核输入和输出是必需且充分的。Mig1磷酸化状态的变化与其定位变化一致，这表明磷酸化可能具有调控作用。我们的结果表明，一种受葡萄糖调控的核输入和/或输出机制控制着Mig1的活性。
