CHROMATIN STRUCTURE IN REGULATION OF MAMMALIAN GENE EXPRESSION

真核生物组织发育相关基因的转录 阶段特异性蛋白质是一个复杂的过程，涉及相互作用， 核染色质与RNA聚合酶II，以及与其他 转录调节因子 珠蛋白的单个成员 基因家族在时间上受到调节， 红系中胚胎、胎儿和成人血红蛋白的表达 许多物种的组织。 对这些基因的研究对人类的进化做出了很大贡献。 我们对选择性转录是如何完成的理解。 的 ε-珠蛋白基因是第一个被发现的β-珠蛋白基因。 在人类发展过程中。 为了研究这方面的规定， 我们已经在体外绘制了基因，核与核之间相互作用的位点， 来自红系和非红系细胞的蛋白质，以及红系和非红系细胞中的DNA序列。 ε-球蛋白启动子。 我们发现红细胞系因子加塔- 1结合 启动子中的三个位点，其他因子，包括SP- 1， 到CACCC和CCAAT网站。 在瞬时表达中使用CAT报告基因构建体 在表达分析中，我们发现在-165位的加塔-1位点是表达所必需的。 通过两个红细胞特异性增强子的转录增强。 本网站 在哺乳动物胚胎球蛋白的进化过程中是保守的 基因. 每个增强子都含有自己的结合位点 对于（通常是相同的）核蛋白质，强调模块的性质， 转录调控区。 在每种情况下， 增强子区域由AP-1基序组成。 因此，生产性 启动子-增强子相互作用增加η-珠蛋白的转录 基因可能需要少至两个蛋白质通过两个调节相互作用， DNA中的位点。

The transcription of eukaryotic genes encoding tissue and developmental stage specific proteins is a complex process involving the interaction of nuclear chromatin with RNA polymerase II, as well as with other transcriptional regulatory factors. The individual members of the globin gene family are temporally regulated to bring about the sequential expression of embryonic, fetal, and adult hemoglobins in the erythroid tissues of many species. The study of these genes has contributed much to our understanding of how selective transcription is accomplished. The epsilon-globin gene is the first of the betalike globin genes to be expressed during human development. To investigate the regulation of this gene we have mapped, in vitro , the sites of interaction between nuclear proteins from erythroid and non-erythroid cells, and DNA sequences in the epsilon-globin promoter. We found that the erythroid factor GATA- 1 bound to three sites in the promoter, and other factors, including SP- 1, bound to the CACCC and CCAAT sites. Using a CAT reporter construct in transient expression assays, we found that the GATA-1 site at -165 is required for transcriptional enhancement by two erythroid specific enhancers. This site has been conserved during the evolution of the mammalian embryonic globin genes. The enhancers each contain their own complement of binding sites for (often the same) nuclear proteins emphasizing the modular nature of transcriptional regulatory regions. In each case the positive-acting regions of the enhancers consisted of AP-1 motifs. Thus, productive promoter-enhancer interactions increasing transcription of the eta-globin gene may require as few as two proteins interacting through two regulatory sites in the DNA.