TRANSCRIPTIONAL MODULATORS AFFECT IN-VIVO PROTEIN FINDING TO THE LOW-DENSITY-LIPOPROTEIN RECEPTOR AND 3-HYDROXY-3-METHYLGLUTARYL COENZYME-A REDUCTASE PROMOTERS
TRANSCRIPTIONAL MODULATORS AFFECT IN-VIVO PROTEIN FINDING TO THE LOW-DENSITY-LIPOPROTEIN RECEPTOR AND 3-HYDROXY-3-METHYLGLUTARYL COENZYME-A REDUCTASE PROMOTERS
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DOI：
10.1074/jbc.270.43.25812
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发表时间：
1995-10-27
影响因子：
4.8
通讯作者：
THOMPSON, JF
中科院分区：
文献类型：
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作者：
LLOYD, DB;THOMPSON, JF
用已知的低密度脂蛋白受体 (LDLR) 基因表达效应物处理 HepGa 细胞，改变了启动子中蛋白质-DNA 相互作用的体内模式。观察到的变化与体内与甾醇调节元件 (SRE)、Sp1 样位点以及 60 个其他区域结合的蛋白质一致。在所有条件下蛋白质都会与 SRE 结合，但硫酸二甲酯反应性的性质会根据细胞的生理状态而变化。当用胆固醇合成抑制剂、胰岛素或佛波醇12-肉豆蔻酸酯13-乙酸酯处理细胞时，观察到低密度脂蛋白受体启动子的SRE内的高甲基化，这表明SRE通过甾醇非依赖性和甾醇依赖性机制调节该启动子。与 Sp1 样位点的结合没有观察到显着变化，这表明与这些位点的差异结合在转录水平的改变中不起作用。对 3-羟基-3-甲基戊二酰辅酶 A 还原酶启动子的分析还揭示了以细胞类型特异性方式变化的保护作用。可以观察到与 3-羟基-3-甲基戊二酰辅酶 A 还原酶 SRE 和推定的核因子 1 位点的结合，但在不同的生理条件下变化很小。
Treatment of HepGa cells with known effecters of low density lipoprotein receptor (LDLR) gene expression altered the in vivo pattern of protein-DNA interactions in the promoter. The observed changes are consistent with proteins binding in vivo to the sterol regulatory element (SRE), to Sp1-like sites, as well as 60 other regions. Protein bound to the SRE in all conditions, but the nature of the dimethyl sulfate reactivity changed depending on the physiological state of the cell. Hypermethylation within the SRE of the low density lipoprotein receptor promoter was observed when cells were treated with cholesterol synthesis inhibitors, insulin, or phorbol 12-myristate 13-acetate, suggesting that the SRE regulates this promoter through sterol-independent as well as sterol-dependent mechanisms. No significant changes were observed in binding to the Sp1-like sites, suggesting that differential binding to these sites does not play a role in altered transcription levels. Analysis of the 3-hydroxy-3-methylglutaryl coenzyme A reductase promoter also revealed protections that varied in a cell type-specific manner. Binding to the 3-hydroxy-3-methylglutaryl coenzyme A reductase SRE and putative nuclear factor 1 sites could be observed but varied little in different physiological conditions.