SETD8 is the sole methyltransferase capable of mono-methylating histone H4, lysine 20. SETD8 and H4K20me1 play a role in a number of essential biologic processes, including cell cycle progression, establishment of higher order chromatin structure, and transcriptional regulation. SETD8 is highly expressed in erythroid cells and erythroid deletion of Setd8 is embryonic lethal by embryonic day 11.5 (E11.5) due to profound anemia, suggesting that it has an erythroid-specific function. The function of SETD8 in the hemopoietic system is poorly understood. The goal of our study was to gain insights into the function of SETD8 during erythroid differentiation. We performed ATAC-seq (assay for transposase-accessible chromatin) on sorted populations of E10.5 Setd8 mutant and control erythroblasts. Accessibility profiles were integrated with expression changes and a mark of heterochromatin (H3K27me3) performed in wild-type E10.5 erythroblasts to further understand the role of SETD8 in erythropoiesis. Data integration identified regions of greater chromatin accessibility in Setd8 mutant cells that co-located with H3K27me3 in wild-type E10.5 erythroblasts suggesting that these regions, and their associated genes, are repressed during normal erythropoiesis. The majority of these more accessible regions were located in promoters and they frequently co-located with the NFY complex. Pathway analysis of genes identified through data integration revealed stemness-related pathways. Among those genes were multiple transcriptional regulators active in multipotent progenitors, but repressed during erythroid differentiation including Hhex, Hlx, and Gata2. Consistent with a role for SETD8 in erythroid specification, SETD8 expression is up-regulated upon erythroid commitment, and Setd8 disruption impairs erythroid colony forming ability. Taken together, our results suggest that SETD8 is an important regulator of the chromatin landscape during erythroid differentiation, particularly at promoters. Our results also identify a novel role for Setd8 in the establishment of appropriate patterns of lineage-restricted gene expression during erythroid differentiation.

中文翻译：

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组蛋白甲基转移酶Setd8在红系分化过程中改变染色质分布并调节关键转录因子的表达

SETD8是能够将组蛋白H4，赖氨酸20单甲基化的唯一甲基转移酶。SETD8和H4K20me1在许多重要的生物学过程中起作用，包括细胞周期进程，高级染色质结构的建立和转录调控。SETD8在红系细胞中高表达，由于深度贫血，在胚胎第11.5天（E11.5）时，Setd8的红系缺失在胚胎中具有致命性，这表明它具有红系特异性功能。SETD8在造血系统中的功能了解甚少。我们研究的目的是深入了解红系分化过程中SETD8的功能。我们对E10.5 Setd8突变体和对照成红细胞的分类群体进行了ATAC-seq（转座酶可及染色质测定）。可访问性配置文件与表达变化和异染色质（H3K27me3）标记整合在一起，用于在野生型E10.5红细胞中进行，以进一步了解SETD8在红细胞生成中的作用。数据整合确定了在野生型E10.5成红细胞中与H3K27me3并存的Setd8突变细胞中，染色质可及性更高的区域，表明这些区域及其相关基因在正常的红细胞生成过程中受到抑制。这些更容易接近的区域大部分位于启动子中，并且经常与NFY复合体位于同一位置。通过数据整合确定的基因的途径分析揭示了干性相关途径。这些基因中有多个在多能祖细胞中活跃的转录调节因子，但在红系分化过程中受到抑制，包括Hhex，Hlx，和Gata2。与SETD8在类红细胞规范中的作用一致，SETD8的表达在类红细胞发生时上调，而Setd8的破坏会破坏类红细胞集落形成能力。两者合计，我们的结果表明，SETD8是红系分化过程中尤其是启动子时染色质格局的重要调节剂。我们的研究结果还确定了Setd8在红系分化过程中建立谱系限制性基因表达的适当模式中的新作用。特别是在发起人身上。我们的研究结果还确定了Setd8在红系分化过程中建立谱系限制性基因表达的适当模式中的新作用。特别是在发起人身上。我们的研究结果还确定了Setd8在红系分化过程中建立谱系限制性基因表达的适当模式中的新作用。