Control of the Erythroid Terminal Differentiation Decision

红细胞终末分化决策的控制

• 批准号: 8667435
• 负责人: ARTHUR I SKOULTCHI
• 金额: $ 36.32万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8667435
• 关键词: ATP phosphohydrolase; Acute; Address; Anemia; Binding; Blood; Cell Count; Cell Cycle; Cell Cycle Progression; Cell Differentiation process; Cell Proliferation; Cell Proliferation Regulation; Cells; Chronic; Complex; Cyclin D1; DNA Methylation; DNA Methyltransferase; DNA Modification Methylases; Defect; Development; Down-Regulation; Embryo; Enzymes; Equilibrium; Erythrocyte Transfusion; Erythrocytes; Erythroid; Erythroid Cells; Erythropoiesis; Family; Fetal Liver; G1 Phase; Gene Expression; Gene Targeting; Genes; Genetic Transcription; Goals; Growth; Hematologic Neoplasms; Hematopoietic; Hematopoietic System; Intervention; Knockout Mice; Knowledge; Lead; Link; Maintenance; Mediating; Output; Phosphotransferases; Play; Process; Production; Proliferating; Property; Recruitment Activity; Regulation; Regulatory Element; Repression; Role; S Phase; SMARCA5 gene; SPI1 gene; Series; Source; Stress; System; Work; chromatin remodeling; erythroid differentiation; human GATA1 protein; insight; novel strategies; progenitor; programs; promoter; proto-oncogene protein Spi-1; public health relevance; research study; self-renewal; transcription factor

DESCRIPTION (provided by applicant): The overall goal of this project is to elucidate the factors and mechanisms that control the decision of early erythroid progenitors to undertake terminal differentiation. Much evidence suggests that a crucial aspect of differentiation decisions is a requirement for coordination with the cell proliferation program. However, our current knowledge about the connections between the cell proliferation and differentiation programs is very limited. Work from our lab and others has identified the Ets - family transcription factor PU.1 as a key regulator of the terminal differentiation decision in early erythroid progenitors. And yet, the factors that control PU.1 expression and activity in these early erythroid progenitors and the mechanisms that link the differentiation decision to the cell cycle are not known. Recently, we identified two types of factors that have a very strong potential for connecting PU.1 and the terminal differentiation decision to the cell cycle. One factor is CDK6, which we discovered inhibits erythroid differentiation, like PU.1. We also showed that: 1) CDK6 is the active G1 phase D-cyclin kinase in erythroid progenitors; 2) PU.1 controls transcription of the CDK6 gene; 3) CDK6 phosphorylates PU.1. The other factors are E2F2 and E2F4, transcriptions factors that play major roles in G1 to S phase cell cycle progression. We found that E2F2 and E2F4 occupy the promoter and upstream regulatory element (URE) of the PU.1 gene in erythroid progenitors. They also bind very close to PU.1 at many other PU.1 target genes in these cells. In Aims 1 and 2, we propose a series of experiments to determine how CDK6 and E2F2 and E2F4 influence PU.1 expression and activity and how they collaborate with PU.1 in the erythroid terminal differentiation decision. We also propose to investigate roles for CDK6 and E2F2 in stress erythropoiesis and in ex vivo self-renewal of erythroid precursors. Work from our lab and others showed that one of the principal mechanisms used by PU.1 to regulate the erythroid differentiation decision is repression of erythroid-specific gene expression Recently, we discovered that PU.1 forms a complex with the chromatin remodeling ATPase SNF2H and the maintenance DNA methyltransferase DNMT1; two enzymes that we hypothesize help PU.1 to repress erythroid gene expression. In Aim 3, we propose studies to elucidate the role of SNF2H and DNMT1 in PU.1-mediated repression of erythroid-specific genes and inhibition of erythroid terminal differentiation. The successful completion of the proposed studies will lead to new insights into the mechanisms connecting the proliferation and differentiation programs in hematopoietic cells and a much deeper understanding of how the hematopoietic system regulates red blood cell production, including during ontogeny and in stress conditions. The proposed work will also provide important information enabling the development of new approaches to managing defects in red blood cell production that occur in chronic and acute anemia.

描述（由申请人提供）：该项目的总体目标是阐明控制早期红系祖细胞进行终末分化的决定的因素和机制。许多证据表明，差异化决策的一个关键方面 是与细胞增殖程序协调的要求。然而，我们目前对细胞增殖和分化程序之间的联系的了解非常有限。我们实验室和其他人的工作已确定 Ets - 家族转录因子 PU.1 是早期红系祖细胞终末分化决策的关键调节因子。然而，控制这些早期红系祖细胞中 PU.1 表达和活性的因素 将分化决定与细胞周期联系起来的机制尚不清楚。最近，我们发现了两种类型的因子，它们在将 PU.1 和终末分化决策与细胞周期联系起来方面具有很强的潜力。其中一个因素是 CDK6，我们发现它会抑制红细胞分化，就像 PU.1 一样。我们还表明：1) CDK6 是红系祖细胞中活跃的 G1 期 D-细胞周期蛋白激酶； 2) PU.1控制CDK6基因的转录； 3) CDK6 磷酸化 PU.1。其他因子是 E2F2 和 E2F4，它们是在 G1 到 S 期细胞周期进程中发挥主要作用的转录因子。我们发现E2F2和E2F4占据了红系祖细胞中PU.1基因的启动子和上游调控元件(URE)。它们还在这些细胞中的许多其他 PU.1 靶基因处与 PU.1 结合非常紧密。在目标 1 和 2 中，我们提出了一系列实验来确定 CDK6 和 E2F2 和 E2F4 如何影响 PU.1 表达和活性，以及​​它们如何在红细胞终末分化决策中与 PU.1 协作。我们还建议研究 CDK6 和 E2F2 在应激红细胞生成和红细胞前体体外自我更新中的作用。我们实验室和其他实验室的工作表明，PU.1 调节红细胞分化决策的主要机制之一是抑制红细胞特异性基因表达。最近，我们发现 PU.1 与染色质重塑 ATP 酶 SNF2H 和维持 DNA 甲基转移酶 DNMT1 形成复合物；我们假设有两种酶有助于 PU.1 抑制红细胞基因表达。在目标 3 中，我们提出研究阐明 SNF2H 和 DNMT1 在 PU.1 介导的红系特异性基因抑制和红系终末分化抑制中的作用。拟议研究的成功完成将为连接造血细胞增殖和分化程序的机制提供新的见解，并更深入地了解造血系统如何调节红细胞的产生，包括在个体发育期间和应激条件下。拟议的工作还将提供重要信息，从而能够开发新方法来管理慢性和急性贫血中出现的红细胞生成缺陷。