Transcriptional Control of Hemoglobin Synthesis and Erythrocyte Development

项目总结 血红蛋白合成和红细胞发育通常是独立研究的，但它们的机制是 千丝万缕的联系。分化缺陷会产生未成熟的前体细胞，而血红蛋白合成受损会导致 无效的红细胞生成。这些机制的一个共同线索是GATA转录因子的参与。 关于GATA因子网络如何指示祖先产生大量的 红细胞，它广泛地为分子/细胞生物学和血液学提供信息。我们发现：1)特定于基因座 GATA1利用辅调节因子调控分化；2)GATA因子/再生激活增强子 允许表达一种未研究的控制红细胞再生的无菌α基序结构域蛋白；3) GATA因子调控的锌转运蛋白开关调控分化；4)血红素靶向染色质的机制 全基因组；5)GATA因子调节的溶质载体蛋白(SLC)队列运输不同的小分子 控制红血球生成。我们的多组学工作支持了分析GATA因素如何建立小的 以基因组为靶点并调节GATA因子以确保分化的分子集合。目标1将 剖析GATA1和血红素控制基因组功能的多组分机制 红细胞发育。GATA1激活介导血红素生物合成的基因，血红素促进或限制 GATA1功能和血红素下调GATA1。亚铁血红素通过下调基因转录调节转录 抑制因子Bach1，我们发现了一种不依赖Bach1的血红素调节机制。我们假设 Bach1依赖和非独立的机制建立了关键的红系功能，这些机制 提供翻译机会。利用所有的血红素目标基因和基因特异性的方法，我们将建立 这些机制。目标2将阐明依赖GATA因子的小分子转运体轴 调节红系分化。我们假设不同的小分子在GATA因子中起作用 GATA因子调节的溶质载体(SLC)转运体的机制和发现将揭示新的维度 这些机制。我们定义了一个受GATA1/2调控的SLC队列，它运输不同的小分子。我们 用GATA因子占据的预测增强子确定子集的优先顺序，并将阐明连接机制 GATA因子与小分子系综和分化。AIM 3将测试GATA1如何 煽动依赖鞘磷脂的调控网络。GATA1调节的SLC包括鞘脂 传送者。脂质组学显示GATA1诱导的鞘脂重塑。神经酰胺合成酶抑制块 GATA1介导的GATA2下调、β-珠蛋白诱导和红系成熟。鞘脂信号 控制细胞凋亡、增殖和迁移，高S1P在镰状细胞疾病中有害，而人类 神经酰胺缺乏症包括红细胞生成受阻。我们假设鞘磷脂的调节是通过 GATA1在生物学和病理学中都是至关重要的。我们将发展对GATA因素的基本和翻译见解 控制GATA因子、珠蛋白合成和分化的小分子机制。

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.