CHROMATIN STRUCTURE IN REGULATION OF MAMMALIAN GENE EXPRESSION

编码组织和发育的真核基因的转录 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 以及其他 转录调节因子。 球蛋白的个体成员 基因家族受到暂时调节以产生顺序 胚胎、胎儿和成人血红蛋白在红细胞中的表达 许多物种的组织。 对这些基因的研究做出了很大贡献 我们对选择性转录如何完成的理解。 的 ε-珠蛋白基因是第一个被证实的β样珠蛋白基因 在人类发展过程中表现出来。 为调查该规定 我们已经在体外绘制了基因图谱，核之间相互作用的位点 来自红细胞和非红细胞的蛋白质，以及DNA序列 ε-珠蛋白启动子。 我们发现红细胞因子 GATA-1 结合 到启动子中的三个位点，以及其他因子，包括 SP-1，结合 到 CACCC 和 CCAAT 网站。 在瞬态中使用 CAT 报告构建体 表达分析中，我们发现 -165 处的 GATA-1 位点是 两个红细胞特异性增强子的转录增强。 这个网站 在哺乳动物胚胎珠蛋白的进化过程中一直被保守 基因。 每个增强子都包含自己的结合位点补充 对于（通常是相同的）核蛋白，强调其模块化性质 转录调控区。 在每种情况下，积极作用 增强子区域由 AP-1 基序组成。 因此，富有成效的 启动子-增强子相互作用增加eta-珠蛋白的转录 基因可能只需要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.