A negative cis-element regulates the level of enhancement by hypersensitive site 2 of the β-globin locus control region
A negative cis-element regulates the level of enhancement by hypersensitive site 2 of the β-globin locus control region
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DOI：
10.1074/jbc.m009624200
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发表时间：
2001-03-02
影响因子：
4.8
通讯作者：
Hardison, R
中科院分区：
文献类型：
--
作者：
Elnitski, L;Li, J;Hardison, R
来自β-珠蛋白基因座控制区的DNA酶超敏位点（HS）2的核心是珠蛋白基因表达的有效增强子。虽然它已被认为只含有正顺式调控序列，我们的研究增强赋予的片段HS 2在红系细胞揭示了一种新的负元素。来自HS 2的单个顺式调节元件如E盒或Maf-反应元件产生与小鼠红白血病（MEL）细胞中的完整核心一样大或更大的增强，表明HS 2内存在负元件。通过HS 2的一系列缺失揭示了在核心的5'和3'端的负元件。对含有和不含5'负元件的构建体的分析表明，该效应作用于在胚胎、胎儿或成体阶段表达的珠蛋白基因的启动子。在双能人细胞（K562和人红白血病（HEL）细胞）、前成红细胞小鼠（MEL）细胞和正常成人红系细胞中观察到了负面效应。新的负元件在稳定整合到MEL染色体中后也起作用。在HS 2核心的5'端的较小缺失将阴性元件映射在含有两个保守序列的20个碱基对区域内。
The core of DNase hypersensitive site (HS) 2 from the beta -globin locus control region is a potent enhancer of globin gene expression. Although it has been considered to contain only positive cis-regulatory sequences, our study of the enhancement conferred by segments of HS2 in erythroid cells reveals a novel negative element. Individual cis-regulatory elements from HS2 such as E boxes or Maf-response elements produced as great or greater enhancement than the intact core in mouse erythroleukemia (MEL) cells, indicating the presence of negative elements within HS2. A deletion series through HS2 revealed negative elements at the 5' and 3' ends of the core. Analysis of constructs with and without the 5' negative element showed that the effect is exerted on the promoters of globin genes expressed at embryonic, fetal, or adult stages. The negative effect was observed in bipotential human cells (K562 and human erythroleukemia (HEL) cells), proerythroblastic mouse (MEL) cells, and normal adult human erythroid cells. The novel negative element also functions after stable integration into MEL chromosomes. Smaller deletions at the 5' end of the HS2 core map the negative element within a 20-base pair region containing two conserved sequences.