Transcriptional Control of Hemoglobin Synthesis and Erythrocyte Development

项目摘要 血红蛋白的合成和红细胞的发育通常是独立研究的，但它们的机制， 密不可分分化缺陷产生不成熟的前体，受损的血红蛋白合成导致 无效的红细胞生成。这些机制的共同线索是加塔转录因子参与。 关于加塔因子网络如何指导祖细胞产生大量的 红细胞，其广泛地告知分子/细胞生物学和血液学。我们发现：1）基因座特异性 GATA 1利用辅助调节子控制分化; 2）加塔因子/再生激活增强子 赋予控制红细胞再生的未研究的不育α基序结构域蛋白的表达; 3） 加塔因子调控的锌转运开关调控分化; 4）血红素靶向染色质的机制 全基因组; 5）加塔因子调节的溶质载体蛋白（SLC）群组转运多种小分子 来控制红细胞生成我们的多组学工作支持分析加塔因素如何建立小 靶向基因组并调节加塔因子以确保分化的分子集合。目标1将 剖析GATA 1和血红素控制基因组功能的多组分机制， 红细胞发育GATA 1激活基因介导血红素生物合成，血红素促进或限制 GATA 1功能和血红素下调GATA 1。血红素通过下调 阻遏Bach 1，我们发现了一个Bach 1独立的血红素调节机制。我们假设 Bach 1依赖性和非依赖性机制建立了关键的红细胞功能，这些机制 提供翻译机会。使用所有血红素靶基因和基因特异性方法，我们将建立 机制。目的2将阐明一个加塔因子依赖的小分子转运轴， 调节红细胞分化。我们假设不同的小分子在加塔因子中起作用， 机制和发现加塔因子调节的溶质载体（Slc）转运蛋白将揭示新的维度 这些机制。我们定义了一个GATA 1/2调节的Slc队列，它转运多种小分子。我们 优先考虑具有加塔因子占据的预测增强子的子集，并将阐明将 具有小分子集合和分化的加塔因子。Aim 3将测试GATA 1 引发了一个依赖鞘脂的调节网络。GATA 1调节的SLCs包括鞘脂 运输机脂质组学显示GATA 1诱导的鞘脂重塑。神经酰胺合酶抑制阻断剂 GATA 1介导的GATA 2下调、β-珠蛋白诱导和红细胞成熟。鞘脂信号 控制细胞凋亡、增殖和迁移，高S1 P在镰状细胞病中是有害的， 神经酰胺缺乏涉及红细胞生成的破坏。我们假设，神经鞘脂的调节， GATA 1在生物学和病理学中至关重要。我们将发展对加塔因素的基本和翻译见解 控制加塔因子、球蛋白合成和分化的小分子的机制。

PROJECT SUMMARY Hemoglobin synthesis and erythrocyte development are often studied independently, yet their mechanisms are inextricably linked. Differentiation defects yield immature precursors, and impaired hemoglobin synthesis causes ineffective erythropoiesis. A common thread of these mechanisms is GATA transcription factor involvement. Many questions remain regarding how GATA factor networks instruct progenitors to generate vast numbers of erythrocytes, which broadly informs molecular/cellular biology and hematology. We discovered: 1) locus-specific coregulator utilization by GATA1 to control differentiation; 2) GATA factor/regeneration-activated enhancer confers expression of an unstudied sterile alpha motif domain protein that controls erythrocyte regeneration; 3) GATA factor-regulated zinc transporter switch governs differentiation; 4) mechanism of heme targeting chromatin genome-wide; 5) GATA factor-regulated solute carrier protein (SLC) cohort transports diverse small molecules to control erythropoiesis. Our multi-omic work supports the aims to analyze how GATA factors establish small molecule ensembles that target the genome and regulate the GATA factor to ensure differentiation. Aim 1 will dissect a multi-component mechanism by which GATA1 and heme control genome function and erythrocyte development. GATA1 activates genes mediating heme biosynthesis, heme facilitates or restricts GATA1 function and heme downregulates GATA1. Heme regulates transcription by downregulating the repressor Bach1, and we discovered a Bach1-independent heme-regulated mechanism. We hypothesize that Bach1-dependent and -independent mechanisms establish critical erythroid functions, and these mechanisms provide translational opportunities. Using all heme target genes and a gene-specific approach, we will establish the mechanisms. Aim 2 will elucidate a GATA factor-dependent small molecule transporter axis that regulates erythroid differentiation. We hypothesize that diverse small molecules function in GATA factor mechanisms and discovering GATA factor-regulated solute carrier (Slc) transporters will unveil new dimensions to these mechanisms. We defined a GATA1/2-regulated Slc cohort that transports diverse small molecules. We prioritized a subset with GATA factor-occupied predicted enhancers and will elucidate mechanisms that link GATA factors with small molecule ensembles and differentiation. Aim 3 will test models for how GATA1 instigates a sphingolipid-dependent regulatory network. GATA1-regulated Slcs included sphingolipid transporters. Lipidomics revealed GATA1-induced sphingolipid remodeling. Ceramide synthase inhibition blocks GATA1-mediated GATA2 downregulation, β-globin induction and erythroid maturation. Sphingolipid signaling controls apoptosis, proliferation and migration, high S1P is deleterious in sickle cell disease, and human ceramide deficiency involves disrupted erythropoiesis. We hypothesize that sphingolipidome regulation by GATA1 is vital in biology and pathology. We will develop basic and translational insights into GATA factor mechanisms governing small molecules that control GATA factors, globin synthesis and differentiation.