Function of RUNX1 in diverse Down syndrome tissues

项目摘要 父母建议：RUNX1，也被称为急性髓系白血病1蛋白(AML1)，是一种 转录因子在造血谱系的规范中起着关键作用 在胚胎发育过程中，它是整个出生后正常巨核生成所必需的 生活。RUNX1基因定位于21号染色体的q22.12带，该带是21号染色体的三倍体 21三体(T21)个体。出于这个原因，建议额外复制一份RUNX1 在唐氏综合征(DS)相关的血液学改变中发挥相关作用。我们 试图破译RUNX1对唐氏综合症患者表型的贡献 综合症。由于转录因子与DNA结合并改变RNA聚合酶的活性，我们将 确定在唐氏综合症来源的细胞中，RUNX1的这两个功能是否发生了变化。我们会 还定义了增强或抑制RUNX1功能的药物在具有 额外的21号染色体拷贝。最后，我们将确定有多少被改变的血液 唐氏综合征的分化是由RUNX1通过使RUNX1基因正常化而引起的 三体背景下的剂量(例如，三体细胞系中的两个拷贝)。然后我们将分析 诱导IPSCs分化为类胚体和血细胞。总体而言，这项工作将 对RUNX1的功能以及它在21三体中是如何改变的重要见解。 补充项目摘要：Gialesaki等人最近的一份报告。(2023年3月)成立了 RUNX1选择性剪接和异构体失衡的关键作用--而不是整体 表达-作为唐氏综合征相关髓系白血病(DS-ML)的主要驱动因素。这些 调查结果对我们提案的大多数具体目标具有重要影响。因此，我们 应该部分修改我们的一些子目标，以评估RUNX1剪接的相关性 DS来源的IPSC和淋巴母细胞分化的不同结果的平衡 和动态平衡。本补充的第二个动机仅适用于Aim 3。 我们最初建议通过敲除T21中的一个拷贝来使RUNX1基因剂量正常化 //− IPSC系列(T21 RUNX1)。我们现在提出替代战略来克服这种 障碍，并纳入刚才提到的针对特定异构体的分析。此管理 附录涉及组成部分1：一项有针对性的高风险-高回报的基础科学研究 这与唐氏综合征的白血病风险有关。此外，这一副刊将显着 提高该项目的科学意义，促进对 控制T21患者血液学改变的潜在机制。

Project Summary Parent Proposal: RUNX1, also known as Acute Myeloid Leukemia 1 protein (AML1), is a transcription factor that plays a critical function in the specification of the hematopoietic lineage during embryogenesis and is required for normal megakaryopoiesis throughout the postnatal life. The RUNX1 gene is localized to band q22.12 of chromosome 21, which is triplicated in individuals with Trisomy 21 (T21). For this reason, an extra copy of RUNX1 has been proposed to play relevant roles in the hematological alterations associated with Down syndrome (DS). We seek to decipher the contribution of RUNX1 to the phenotypes seen in individuals with Down syndrome. Since transcription factors bind to DNA and alter RNA polymerase activity, we will determine if those two functions of RUNX1 are altered in Down syndrome-derived cells. We will also define if drugs that increase or inhibit RUNX1 function behave differently in cells with an extra copy of chromosome 21. Finally, we will ascertain how much of the altered blood differentiation seen in Down syndrome is caused by RUNX1 by ‘normalizing’ RUNX1 gene dosage in a trisomy background (e.g., two copies in a trisomy cell line). We will then analyze the differentiation of iPSCs into embryoid bodies and blood cells. Collectively this work will shed important insights into the functions of RUNX1 and how it is altered in Trisomy 21. Supplement Project Summary: A recent report by Gialesaki et al. (March 2023) established a critical role for RUNX1 alternative splicing and isoform imbalance -rather than overall expression- as a major driver of Down syndrome-associated myeloid leukemia (DS-ML). These findings have important implications on most of the specific aims of our proposal. Therefore, we should partially modify some of our sub-aims to assess the relevance of RUNX1 splicing equilibrium on the different outcomes of DS-derived iPSC and lymphoblastoid cell differentiation and homeostasis. A second motivation for this supplement applies exclusively to Aim 3. Here we orginally proposed to normalize RUNX1 gene dosage by knocking-out one copy in the T21 +/+/− iPSC line (T21 RUNX1 ). We now propose alternative strategies to overcome such obstacles and incorporate the isoform-specific analyses just mentioned. This Administrative Supplement addresses Component 1: A targeted high risk - high reward basic science study that is relevant to Leukemia risk in Down syndrome. Moreover this supplement will significantly improve the scientific significance of the project by contributing to a better understanding of the underlying mechanisms that govern hematological alterations in individuals with T21.