Determinants of epigenetic inheritance in human stem cell fate decisions

项目摘要 在造血干细胞中，表观基因组赋予自我更新和分化功能 其中HSC染色质状态的遗传在细胞周期中是持续的。我的博士后研究集中在 关于一个基本的表观遗传特征，涉及预先存在的亲本核小体的局部再循环， 研究表明，抑制，但不活跃，染色质结构域是通过DNA复制遗传的。而 鉴定促进小鼠中抑制的染色质结构域遗传的组蛋白伴侣 在胚胎干细胞中，我发现核磷蛋白NPM1在这一过程中起着重要作用。NPM1是 一种组蛋白伴侣，其基因突变和重排在约30%的成人AML中发现，然而， 其在正常造血中的功能仍然未知。此外，关键问题仍然存在于继承问题上， H3K27me染色质结构域，例如NPM1和多梳抑制复合物2（PRC2） 到DNA复制叉在S期，多梳染色质结构域是如何在发育中遗传的？ 免疫系统，以及亲本核小体分离是否在免疫系统之间的精确平衡中发挥作用。 形成造血级联的自我更新和分化能力。在这份提案中，我的团队将 确定构建可遗传的人类HSC表观基因组的分子基础， 染色质动力学提供HSC自我更新和分化的能力。我们将在体外使用 人诱导多能干细胞并使其分化以获得造血祖细胞命运。 利用这一系统，我们将进行切割年龄基因组工程，蛋白质组学和成像技术， 发现组蛋白伴侣和polycomb在构建HSC可遗传表观基因组中的作用。

Project summary In hematopoietic stem cells (HSCs), the epigenome confers self-renewal and differentiation functions wherein inheritance of HSC chromatin states is persistent across cell cycles. My postdoctoral studies focused on a fundamental epigenetic feature involving the local recycling of pre-existing, parental nucleosomes, which showed that repressed, but not active, chromatin domains are inherited across DNA replication. While identifying the histone chaperone(s) that facilitate the inheritance of repressed chromatin domains in mouse embryonic stem cells, I discovered that nucleophosmin, NPM1, plays an essential role in this process. NPM1 is a histone chaperone whose genetic mutation and rearrangement are found in ~30% of all adult AML, however its function in normal hematopoiesis remains unknown. Furthermore, key questions persist on the inheritance of H3K27me chromatin domains, such as what brings NPM1 and the polycomb repressive complex 2 (PRC2) to the DNA replication fork during S-phase, how are polycomb chromatin domains inherited in the developing immune system, and whether parental nucleosome segregation has a role in the precise balancing between self-renewal and differentiation capacities that shape a hematopoietic cascade. In this proposal, my group will identify the molecular basis for constructing the heritable human epigenome of HSCs and discover the chromatin dynamics that provide HSCs the ability to both self-renew and differentiate. We will use in vitro human induced pluripotent stem cells and differentiate them to derive a hematopoietic progenitor cell fate. Using this system, we will conduct cutting age genome engineering, proteomics, and imaging technologies to discover the function of histone chaperones and polycomb in constructing the heritable epigenome of HSCs.