Transcriptional Regulatory Networks Active in Terminal Erythroid Differentiation

描述（由申请人提供）： 作为一名儿科血液学家，我觉得非常有必要了解在我的患者群体中发现的某些获得性和先天性再生障碍性贫血和白血病中发生的分化和增殖失调背后的机制。现代医学通常能为这些患者提供的最多的就是骨髓移植。考虑到这一困境，我从事血液学基础实验室科学的职业，因此旨在了解红细胞生成的调节。我认为当前的研究项目是该领域独立研究人员所需的生物学、研究技术和信息操作方面的强化培训，同时发现可能的新基因或对分化过程本身的新见解。达纳法伯癌症研究所和怀特海德研究所的研究环境、出色的指导以及合作者、设备、课程和同事等资源将独特地帮助我实现我的职业目标。 促红细胞生成素 (Epo) 及其同源受体 EpoR 部分通过信号转导器和转录激活剂 5 (Stat5) 诱导抗凋亡蛋白 bcl-xL 来确保早期红细胞前体细胞的存活。 Epo 与 EpoR 结合导致多种信号转导途径的激活，包括磷脂酰肌醇 3 激酶 (Pi3K)/AKT 激酶、ras/丝裂原激活蛋白激酶 (MAPK) 和 Stat5 途径，这些途径还启动红细胞特异性表达和建立红细胞表型的细胞程序。然而，这些途径并不是红系谱系所独有的：Stat5 激活发生在不同组织中众多细胞因子受体的下游，调节截然不同的组织表型。据推测，这些通用的细胞因子诱导的转录因子需要与预先存在的组织特异性因子相互作用才能发挥其功能。红细胞重要的调节蛋白 GATA1 和 FOG（GATA1 的朋友）也被认为是正常红细胞生成所必需的。为了阐明细胞因子激活和组织特异性调节蛋白如何共同启动组织的独特表达程序，我打算使用染色质免疫沉淀和启动子微阵列确定 Stat5、GATA1 和 FOG 在不同分化阶段的直接靶标。我计划使用创新的生物信息学策略以及表达谱来验证我的位置数据并建立红细胞生成转录调控的轮廓。 基因如何指导不同细胞类型中的蛋白质成为独特的组织，可能是这种指令在贫血和白血病等疾病中出错的基础。我计划了解红细胞发育生物学中的这个程序，希望找到治疗这些疾病的新疗法。

DESCRIPTION (provided by applicant): As a pediatric hematologist, I feel a great need to understand the mechanisms behind the dysregulation of differentiation and proliferation that occur in certain acquired and congenital aplastic anemias and leukemias found in my patient population. The most that modern medicine can often offer these patients is bone marrow transplant. I pursue a career in basic laboratory science in hematology with this quandary in mind, and thus aim to understand the regulation of erythropoiesis. I envision this current research project as intensive training in the biology, research techniques, and information manipulation that are required of an independent investigator in this field, while at the same time, uncovering possible novel genes or new insight into the process of differentiation itself. The research environment, outstanding mentorship, and resources in the form of collaborators, equipment, classes, and colleagues at the Dana Farber Cancer Institute and the Whitehead Institute will uniquely assist me in achieving my career goals. Erythropoietin (Epo) and its cognate receptor, EpoR, ensure the survival of early erythroid precursors in part through induction of the anti-apoptotic protein bcl-xL by the Signal transducer and activator of transcription 5 (Stat5). Epo binding to EpoR results in activation of several signal transduction pathways including the Phosphatidylinositol 3 kinase (Pi3K)/AKT kinase, ras/Mitogen-Activated Protein Kinase (MAPK), and Stat5 pathways, which also initiate the erythroid-specific expression and cellular programs that establish the erythroid phenotype. However, these pathways are not unique to the erythroid lineage: Stat5 activation occurs downstream of numerous cytokine receptors in diverse tissues, regulating vastly different tissue phenotypes. Presumably, these generic, cytokine-induced transcription factors require interaction with pre-existing tissue-specific factors in order to exert their function. Erythroid-important regulatory proteins, GATA1 and FOG (friend of GATA1), are also known to be essential for normal erythropoiesis. In order to elucidate how cytokine-activated and tissue-specific regulatory proteins can collectively initiate the unique expression programs of a tissue, I intend to determine the direct targets of Stat5, GATA1, and FOG in distinct stages of differentiation using chromatin immunoprecipitation and promoter microarrays. I plan to use innovative bioinformatics strategies as well as expression profiling to validate my location data and establish an outline for the transcriptional regulation of erythropoiesis. How genes instruct proteins in different cell types to become unique tissues is probably the basis for how this instruction can go awry in diseases like anemias and leukemias. I plan to understand this program in the biology of red blood cell development, in hopes of discovering new treatments for these disorders.