Multiple regions of p45 NF-E2 are required for beta-globin gene expression in erythroid cells
Multiple regions of p45 NF-E2 are required for beta-globin gene expression in erythroid cells
复制标题
DOI：
10.1093/nar/25.12.2509
复制
发表时间：
1997-06-15
影响因子：
14.9
通讯作者：
Ney, PA
中科院分区：
文献类型：
--
作者：
Bean, TL;Ney, PA
β-珠蛋白簇中基因的调节表达取决于位于β-珠蛋白基因上游5至20 kb之间的序列，称为基因座控制区（LCR）。β-珠蛋白在鼠红白血病（MEL）细胞中的表达依赖于NF-E2，NF-E2是一种与LCR中的增强子序列结合的转录因子。为了深入了解NF-E2激活珠蛋白基因的机制，使用NF-E2无效MEL细胞系来定位β-珠蛋白表达所需的NF-E2区域。在反式激活结构域中，需要两个离散的富含脯氨酸的区域来拯救β-珠蛋白表达。第一个位于NF-E2的N-末端，而第二个位于帽领（CNC）结构域的N-末端。其他富含脯氨酸的序列被排除，表明脯氨酸含量本身并不决定NF-E2活性。保守的CNC结构域内的突变显著减少了β-珠蛋白表达的拯救。除了碱性亮氨酸拉链结构域之外，该结构域是DNA结合活性所需的。反式激活结构域内离散的富含脯氨酸的序列的要求表明，珠蛋白基因在MEL细胞中的表达取决于NF-E2和下游效应分子之间的特异性相互作用。
Regulated expression of genes in the beta-globin cluster depends upon sequences located between 5 and 20 kb upstream of the epsilon gene, known as the locus control region (LCR). beta-Globin expression in murine erythroleukemia (MEL) cells depends on NF-E2, a transcription factor which binds to enhancer sequences in the LCR. To gain insight into the mechanism of globin gene activation by NF-E2, an NF-E2 null MEL cell line was used to map regions of NF-E2 required for beta-globin expression. Within the transactivation domain, two discrete proline-rich regions were required for rescue of beta-globin expression. The first was located at the N-terminus of NF-E2, while the second was located N-terminal of the cap 'n collar (CNC) domain. Other proline-rich sequences were dispensable, indicating that proline content per se does not determine NF-E2 activity. Mutations within the conserved CNC domain markedly diminished rescue of beta-globin expression. This domain was required, in addition to the basic leucine zipper domain, for DNA binding activity. The requirement for discrete proline-rich sequences within the transactivation domain suggests that globin gene expression in MEL cells depends on specific interactions between NF-E2 and downstream effector molecules.