Genetic modulators of erythro-megakaryocytic development

描述(申请人提供)：编码转录因子GATA-1的基因的体细胞突变与唐氏综合征(DS，21三体)儿童的急性巨核细胞白血病(AMKL)有关，尽管这种遗传相互作用的机制尚不清楚。在初步研究中，我证明了21三体本身增加了人类红系和巨核系祖细胞的增殖能力。在平行的小鼠研究中，我使用了基因操纵的胚胎干细胞来证明GATA-1的缺失促进了双潜能巨核细胞-红系前体细胞(MEPs)的扩张，这是一个类似于AMKL母细胞的群体。通过对突变的MEP进行遗传互补，我发现GATA-1抑制了一个髓系分化程序，部分是通过抑制原癌基因PU.1/Sfpi1的转录。这种影响被AMKL相关的GATA1突变减弱。总而言之，我的发现产生了两个相关的假设：第一，GATA1突变和21三体对造血产生不同的影响，这两个因素共同作用促进白血病。其次，GATA-1通过抑制PU.1/Sfpi1转录促进正常造血，这一过程可能通过与DS-AMKL相关的基因改变而变得失调。这项应用是为了支持一项有指导的研究经验，以阐明GATA-1如何控制正常的造血，以及失调的GATA-1和DS如何在白血病发生中协同作用。我将扩展我在DS胎儿造血方面的研究，以了解21三体扩大红系和巨核系祖细胞的机制(目标1)。我将在体外和小鼠体内检测改变的GATA-1和21三体之间的功能相互作用(目标2)。最后，我将研究野生型和AMKL相关突变形式的GATA-1抑制PU的机制。1/SfpH癌基因转录(目标3)。如果成功，我的研究将为正常红细胞巨核细胞发育的转录控制以及这一过程如何在AMKL中受到干扰提供见解。这项研究的更广泛的影响是更好地了解谱系特异性转录因子在正常组织发育和癌症中的作用。结合我在这项应用中的培训和结构化指导，我相信拟议的研究将为正常和恶性造血提供新的见解，并为我作为儿科内科科学家的职业生涯奠定坚实的基础。

DESCRIPTION (provided by applicant): Somatic mutations in the gene encoding transcription factor GATA-1 are associated with acute megakaryoblastic leukemia (AMKL) in children with Down syndrome (DS, trisomy 21), although the mechanisms underlying this genetic interaction are unknown. In preliminary studies, I demonstrated that trisomy 21 itself increases the proliferative capacity of human erythroid and megakaryocyte progenitors. In parallel murine studies, I used genetically manipulated embryonic stem cells to show that loss of GATA-1 promotes the expansion of bipotential megakaryocyte-erythroid precursors (MEPs), a population that resembles AMKL blasts. Through genetic complementation of the mutant MEPs, I discovered that GATA-1 represses a program of myeloid differentiation, in part by inhibiting transcription of the protooncogene PU.1/Sfpi1. This effect is attenuated by AMKL-associated GATA1 mutations. Together, my findings generate two related hypotheses: First, GATA1 mutations and trisomy 21 produce distinct effects on hematopoiesis, which act together to promote leukemia. Second, GATA-1 promotes normal hematopoiesis by repressing PU.1/Sfpi1 transcription and this process may become dysregulated through genetic alterations associated with DS-AMKL. This application is to support a mentored research experience to elucidate how GATA-1 controls normal hematopoiesis and how dysregulated GATA-1 and DS synergize in leukemogenesis. I will extend my studies in DS fetal hematopoiesis to understand the mechanisms by which trisomy 21 expand erythroid and megakaryocytic progenitors (Aim 1). I will examine functional interactions between altered GATA-1 and trisomy 21 in human hematopoietic progenitors in vitro and in mice (Aim 2). Lastly, I will study the mechanisms by which wild type and AMKL-associated mutant forms of GATA-1 repress PU. 1/SfpH oncogene transcription (Aim 3). If successful, my research will provide insights into the transcriptional control of normal erythromegakaryocytic development and how this process becomes disturbed in AMKL. The broader impact of this research is to better understand how a lineage-specific transcription factor functions in normal tissue development and cancer. Combined with my training and structured mentoring in this application, I believe that the proposed research will provide novel new insights into normal and malignant hematopoiesis and provide a strong foundation to establish my career as a pediatric physician-scientist.