Elucidation of the Role of Setd8 and H4K20me1 in Erythropoiesis

阐明 Setd8 和 H4K20me1 在红细胞生成中的作用

• 批准号: 10544346
• 负责人: LAURIE A. STEINER
• 金额: $ 33.88万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-15 至 2024-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10544346
• 关键词: Acetylation; Affect; Anemia; Cell Cycle; Cell division; Chromatin; Chromatin Structure; Complex; Data; Defect; Disease; Dysmyelopoietic Syndromes; Enhancers; Enzymes; Epigenetic Process; Erythroblasts; Erythrocytes; Erythroid; Erythroid Cells; Erythropoiesis; Failure; Funding; Gene Expression; Gene Expression Profile; Gene Silencing; Goals; Health; Hematopoietic; Higher Order Chromatin Structure; Histone H4; Histones; Human; Impairment; Inherited; Laboratories; Link; Lysine; Mass Spectrum Analysis; Mediating; Methylation; Modeling; Nuclear; Nucleosomes; Output; Pathway interactions; Physical condensation; Play; Population; Post-Translational Protein Processing; Preparation; Process; Production; Proteins; Reader; Red Blood Cell Count; Regulation; Role; Tail; Testing; Time; Transcriptional Regulation; cell type; condensin; design; gene repression; histone methyltransferase; insight; novel; progenitor; recruit; stem cells; transcriptome

Chromatin condensation is a key feature in the terminal maturation of many hematopoietic cell types, but is particularly critical in erythroblasts, which undergo rapid nuclear and chromatin condensation in preparation for enucleation. The average human must generate ~2.5 million red blood cells per second to maintain steady state and avoid anemia. The process of generating an enucleate red blood cell from a committed erythroid progenitor is extremely complex, and requires significant in gene expression during a time of rapid cell division and chromatin condensation. Defects in chromatin condensation are particularly common in inherited anemias and myelodysplastic syndromes, however the specific epigenetic mechanisms that regulate erythroid chromatin condensation, and the relationship between chromatin condensation and gene expression are poorly understood. The goal of this project is to delineate specific epigenetic mechanisms that regulate, and coordinate, changes in gene expression and chromatin structure during terminal erythroid maturation. During the last funding period, we demonstrated that maturing erythroid cells accumulate mono-methylation of histone H4, lysine 20 (H4K20me1). We further demonstrated Setd8, the sole enzyme capable of generating this mark, is essential for erythropoiesis. Disruption of Setd8, and subsequent loss of H4K20me1, resulted in a profound defect in transcriptional repression and defects in chromatin condensation, both globally and at specific loci. The overall goal of this proposal is to delineate mechanisms by which Setd8 and H4K20me1 regulate erythropoiesis. Mass spectrometry studies demonstrated that accumulation of H4K20me1 in maturing erythroblasts was accompanied by loss of histone H4 K16Ac, which interferes with the association of neighboring nucleosomes and promotes histone decompaction, as well as loss of histone H4 lysine 20 dimethylation (H4K20me2), which decreases the ability of histone H4 lysine 20 to interact with epigenetic readers. We hypothesize that this epigenetic transition is an important determinate of gene expression and higher order chromatin structure in maturing erythroblasts. In specific Aim 1, we will determine the mechanisms that establish the H4 chromatin landscape in maturing erythroblasts. H4K20me1 regulates chromatin structure and gene expression through recruitment of epigenetic readers. The only H4K20me1 interacting protein expressed at significant levels in erythroblasts is the Condensin II complex. We demonstrate that the Condensin II subunit NCAPH2 is essential for erythropoiesis. Further, there is significant overlap in the transcriptomes of NCAPH2 / and SETD8 / erythroblasts, supporting a model where Condensin II interacts with H4K20me1 to regulate gene expression and chromatin structure during erythroid maturation. In specific aim 2, we will delineate the mechanisms by which the Condensin II complex regulates terminal erythroid maturation. Together, these studies will provide novel insights into the regulation of terminal erythroid maturation. As chromatin condensation is a common feature of the terminal maturation of many cell types, these studies may have broad implications beyond erythropoiesis.

染色质浓缩是许多造血细胞类型最终成熟的一个关键特征，但是 对于成红细胞尤其重要，其在制备过程中会经历快速的核和染色质浓缩 用于摘除。人类平均每秒必须产生约 250 万红细胞才能保持稳定 状态并避免贫血。从定型红细胞生成去核红细胞的过程 祖细胞极其复杂，在细胞快速分裂期间需要大量的基因表达 和染色质浓缩。染色质浓缩缺陷在遗传性贫血中尤其常见 和骨髓增生异常综合征，然而调节红细胞染色质的特定表观遗传机制 凝集，染色质凝集与基因表达关系较差 明白了。该项目的目标是描述调节和协调的特定表观遗传机制， 红细胞终末成熟过程中基因表达和染色质结构的变化。上次融资期间 在此期间，我们证明成熟的红系细胞积累了组蛋白 H4、赖氨酸 20 的单甲基化 （H4K20me1）。我们进一步证明 Setd8（唯一能够产生此标记的酶）对于 红细胞生成。 Setd8 的破坏以及随后 H4K20me1 的丢失导致了严重的缺陷 全局和特定位点的转录抑制和染色质浓缩缺陷。整体 该提案的目标是描绘 Setd8 和 H4K20me1 调节红细胞生成的机制。 质谱研究表明，成熟红细胞中 H4K20me1 的积累 伴随着组蛋白 H4 K16Ac 的丢失，这会干扰邻近核小体的结合 并促进组蛋白解压缩，以及组蛋白 H4 赖氨酸 20 二甲基化 (H4K20me2) 的损失，这 降低组蛋白 H4 赖氨酸 20 与表观遗传读取器相互作用的能力。我们假设这 表观遗传转变是基因表达和高阶染色质结构的重要决定因素 成熟的红细胞。在具体目标 1 中，我们将确定建立 H4 染色质的机制 成熟红细胞中的景观。 H4K20me1 通过调节染色质结构和基因表达 招募表观遗传学读者。唯一以显着水平表达的 H4K20me1 相互作用蛋白 成红细胞是凝缩蛋白 II 复合物。我们证明凝缩蛋白 II 亚基 NCAPH2 是必不可少的 用于红细胞生成。此外，NCAPH2 / 和 SETD8 / 的转录组存在显着重叠 成红细胞，支持 Condensin II 与 H4K20me1 相互作用调节基因表达的模型 和红细胞成熟过程中的染色质结构。在具体目标 2 中，我们将描述机制 凝缩蛋白 II 复合物调节终末红细胞成熟。这些研究共同将提供新颖的 对终末红细胞成熟调节的见解。由于染色质凝聚是一个共同特征 由于许多细胞类型的最终成熟，这些研究可能具有红细胞生成以外的广泛影响。