The role of the Musashi family in hematopoiesis

描述(由申请人提供)： 在脊椎动物中，造血干细胞(HSC)在维持造血平衡的同时自我更新的多效性能力的调节还不是很清楚。转录后调节因子最近被强调为造血自我更新和细胞命运决定的仲裁者。我们假设“武藏”基因MSI1和MSI2调节造血干细胞的功能，当失调时会导致干细胞紊乱。MSI1和MSI2是密切相关的RNA结合蛋白，通过调节Notch信号影响神经元发育中细胞命运的决定。初步数据表明，MSI家族成员在造血干和祖细胞发育中起着重要作用。在这项为期5年的计划中描述的研究概述了旨在调查MSI基因功能丧失和获得的体内影响的具体目标。这一建议创造了两个新的工具来研究MSI功能：(1)MSI家族的条件敲除(2)MSI家族的敲门TET诱导系统。这两个强大的系统将检验MSI在造血和干细胞功能中的特定作用。具体目标1将利用遗传策略来评估MSI在小鼠造血系统中功能的丧失。具体目标2将通过使用可诱导的MSI1或MSI2过表达来评估MSI失调的作用。可诱导启动子的表达与逆转录病毒移植模型相比具有明显的优势，在逆转录病毒移植模型中，表达水平的差异可能会影响生物学效应，并避免逆转录病毒整合可能产生的伪影。目标3将侧重于武藏的机制和靶点，使其能够在HSC间隔室和髓系分化中发挥调节功能。更具体地说，Notch和β-catenin信号是维持血液中适当分化的核心。最后，这项提案的应用将为在造血干细胞功能的背景下调节这些重要的发育途径提供洞察力。 公共卫生相关性：干细胞疾病包括一大群骨髓增生异常综合征、遗传性和获得性骨衰竭综合征，如再生障碍性贫血。这项建议将加强对干细胞功能调节因子的理解，并可能确定干细胞疾病的新治疗靶点。

DESCRIPTION (provided by applicant): The regulation of the pleiotropic capabilities of hematopoietic stem cells (HSC) to self-renew while maintaining hematopoietic homeostasis in vertebrates is not well understood. Post-transcriptional modulators are recently highlighted as arbiters for hematopoietic self-renewal and cell fate decisions. We hypothesize that the "Musashi" genes MSI1 and MSI2 regulate hematopoietic stem cell function, and when dysregulated contribute to stem cell disorders. MSI1 and MSI2 are closely related RNA-binding proteins that influence cell fate determination in neuronal development by modulating Notch signaling. Preliminary data indicate that MSI family members play an important role in hematopoietic stem and progenitor development. The research described in this 5-year proposal outlines specific aims designed to investigate the in vivo effects of loss and gain of function of Msi genes. This proposal creates two novel tools to study Msi function: (1) a conditional knockouts for the Msi family (2) a knockin tet-inducible system for the Msi family. These two powerful systems will examine the specific role for Msi in hematopoiesis and stem cell function. The Specific Aim 1 will utilize genetic strategies to assess loss of function of Msi in the murine hematopoietic system. Specific Aim 2 will assess the role of Msi dysregulation through use of inducible overexpression of MSI1 or MSI2. Expression of an inducible promoter provides distinct advantages over the retroviral transplant models where differences in expression levels may influence biological effects and avoids possible artifacts from retroviral integrations. Aim 3 will focus on mechanisms and targets of Musashi that enable its regulatory function in the HSC compartment and in myeloid differentiation. More specifically, Notch and beta-catenin signaling is central to maintaining proper differentiation in the blood. Finally, this proposal application will provide insights into Msi regulation of these vital developmental pathways in the context of hemotopoietic stem cell function. PUBLIC HEALTH RELEVANCE: Stem cell disorders comprise a large group of myelodysplastic syndromes, inherited and acquired bone failure syndromes such as aplastic anemias. This proposal will provide enhanced understanding of regulators of stem cell function and may identify novel therapeutic targets for stem cell diseases.