Competition for cellular factors that activate metallothionein gene transcription
Competition for cellular factors that activate metallothionein gene transcription
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激活金属硫蛋白基因转录的细胞因子的竞争
作者：
C. Séguin;B. Felber;A. Carter;D. Hamer
金属硫蛋白（MT）是一种富含半胱氨酸的小分子蛋白质，可与锌、镉、铜等重金属结合并被其诱导。最近的基因转移和诱变实验已经阐明了参与这种形式的regulation 1，2的顺式作用的DNA序列，但没有什么是已知的反式作用因子与控制序列相互作用或这种相互作用如何影响转录速率。我们在这里报告的检测细胞因子参与镉诱导的小鼠MT-I基因的体内竞争试验。我们发现，至少有一类细胞因子通过依赖于最大转录所需的5′侧翼DNA的相同区域的正调控机制起作用。
Metallothioneins (MTs), small cysteine-rich proteins, bind to and are inducible by heavy metals such as zinc, cadmium and copper. Recent gene-transfer and mutagenesis experiments have elucidated cis-acting DNA sequences involved in this form of regulation1,2, but nothing is known about the trans-acting factors that interact with the control sequences or how such interactions influence the rate of transcription. We report here the detection of cellular factors involved in the cadmium induction of the mouse MT-I gene by an in vivo competition assay. We show that at least one class of these cellular factors acts by a positive regulatory mechanism depending on the same region of the 5′ flanking DNArequired for maximal transcription.