Taplitz S J, Calame K L, Herschman H R
Mol Cell Biol. 1986 Jul;6(7):2576-81. doi: 10.1128/mcb.6.7.2576-2581.1986.
We examined the chromatin structure of the rat metallothionein I gene, both in uninduced cells and in cells induced by heavy metals or dexamethasone, using hypersensitivity to DNase I as an assay. The metallothionein I gene of the H4IIE rat hepatoma cell line, expressed at basal level, has a single DNase I-hypersensitive site. This site maps between putative hormone and basal level control sequences. Induction of the gene by cadmium or zinc resulted in the appearance of a new hypersensitive site near the start site of transcription, in a region near the metal-regulatory elements. In contrast, induction of the metallothionein I gene by dexamethasone did not alter the basal pattern of hypersensitivity. Thus, different mechanisms of induction of metallothionein transcription lead to distinct alterations in the chromatin containing the 5' sequences regulating the expression of this gene.
我们以对DNase I的超敏性作为检测方法，研究了大鼠金属硫蛋白I基因在未诱导细胞以及重金属或地塞米松诱导的细胞中的染色质结构。H4IIE大鼠肝癌细胞系中基础水平表达的金属硫蛋白I基因有一个单一的DNase I超敏位点。该位点位于假定的激素和基础水平控制序列之间。镉或锌诱导该基因会导致在转录起始位点附近、靠近金属调节元件的区域出现一个新的超敏位点。相比之下，地塞米松诱导金属硫蛋白I基因并未改变超敏性的基础模式。因此，金属硫蛋白转录的不同诱导机制会导致含有调控该基因表达的5'序列的染色质发生不同改变。
