MacArthur C A, Lieberman M W
J Biol Chem. 1987 Feb 15;262(5):2161-5.
We have examined the chromatin structure of the metallothionein (MT) gene region in MT- S49 mouse lymphoma cells and in derivatives which express MT-I alone, MT-II alone, or both genes. In all lines, these genes are contained in a 16-kilobase pair region between two DNase I sensitive sites: one site located 5.3 kilobase pairs 5' of MT-II (the 5' gene) is present in naked DNA and retained in the chromatin of all lines; the other site located 3.1 kilobase pairs 3' of MT-I is hypersensitive. Hypersensitivity at three other sites is dependent on the expression of MT genes. Two sites 5' of MT-II disappear, and a site 3' of MT-I appears regardless of which gene is activated. The fact that these sites respond when either gene is activated suggests that the regulation of the two genes is interdependent and that the region undergoes a general change in conformation with MT activation. In addition, a single site in the 5' region of MT-II becomes hypersensitive with activation of the gene and may be related directly to expression.
我们已经研究了金属硫蛋白（MT）基因区域在MT - S49小鼠淋巴瘤细胞以及单独表达MT - I、单独表达MT - II或同时表达这两个基因的衍生物中的染色质结构。在所有细胞系中，这些基因位于两个对DNase I敏感位点之间的一个16千碱基对区域内：一个位点位于MT - II（5'基因）的5'端5.3千碱基对处，存在于裸露DNA中，并保留在所有细胞系的染色质中；另一个位点位于MT - I的3'端3.1千碱基对处，具有高敏感性。其他三个位点的高敏感性取决于MT基因的表达。MT - II 5'端的两个位点消失，MT - I 3'端出现一个位点，无论激活的是哪个基因。当任一基因被激活时这些位点都会有反应，这一事实表明这两个基因的调控是相互依赖的，并且随着MT的激活该区域会发生整体构象变化。此外，MT - II 5'区域的一个单个位点随着该基因的激活而变得具有高敏感性，可能与表达直接相关。
