Distinct roles of U2AF1 mutations in myelodysplastic syndrome pathogenesis

项目摘要/摘要 该提案概述了候选人向独立调查员过渡的5年培训计划。 候选人的长期目标是成为一名学术医学中心的内科科学家，研究 骨髓增生异常综合征(MDS)发病机制中基因突变的分子基础 分子病理学实验室。拟议的培训计划将根据应聘者的临床和 科学背景，并为他提供一个支持性的环境，为他的职业生涯做好准备 一名独立调查员。申请者将由马修·沃尔特博士指导，他是MDS遗传学专家 和生物学，华盛顿大学爱德华·埃文斯MDS中心主任(吴)。忠告 由基础科学和临床/翻译MDS专家和病理学家组成的委员会将提供 科学和职业建议。申请人的实验室为这些研究配备了良好的设备，吴提供了 丰富的培训和发展环境，可获得核心设施、科学资源和临床 样品是例外的。本申请中概述的实验旨在阐明不同的 U2AF1突变体在MDS发病机制中，作为剪接因子基因的高度重复杂合突变(例如， U2AF1)发生在超过一半的MDS患者中。U2AF1(编码U2AF1S34和U2AF1Q157)的热点突变 突变)与不同的临床特征、结果、RNA剪接失调和共生有关 MDS患者的基因突变。例如，ASXL1中的截断突变更频繁地与 MDS患者中U2AF1Q157突变高于U2AF1S34突变。候选人已观察到U2af1S34F/+和 U2af1Q157R/+条件性敲入小鼠出现不同的造血表型，包括细胞减少症和 在造血干细胞和造血祖细胞中有不同的基因表达模式和异常的RNA剪接 (HSPC)。这一建议旨在了解U2AF1S34F和U2AF1S34F诱导的不同分子微扰是如何 U2AF1Q157R突变与MDS患者不同的造血表型有关 确定：(1)MYC和mTORC1通路的激活如何导致HSPC功能障碍和多系 U2AF1S34F/+小鼠中的细胞减少以及U2AF1S34F特异性剪接改变是否导致这些细胞的激活 途径，以及(2)突变体ASXL1和U2AF1Q157如何与组蛋白修饰和RNA剪接相关 异常在MDS的发病机制中选择性地协同作用。破译MYC和mTORC1激活的作用 将允许这些模型用于测试改变红细胞减少症的特定途径治疗策略，以及 在体内鉴定ASXL1和U2AF1突变之间的协同作用可能揭示新的机制 在MDS中，RNA剪接和组蛋白修饰协同作用。总而言之，拟议的研究和培训 环境将有助于候选人成功地成为一名独立调查员。

PROJECT SUMMARY/ABSTRACT This proposal outlines a 5-year training plan for the transition of the candidate to an independent investigator. The long-term goal of the candidate is to be a physician-scientist at an academic medical center studying the molecular basis of genetic mutations in myelodysplastic syndrome (MDS) pathogenesis, in addition to directing a molecular pathology laboratory. The training plan proposed will expand upon the candidate's clinical and scientific background and provide him access to a supportive environment that will prepare him for a career as an independent investigator. The applicant will be mentored by Dr. Matthew Walter, an expert in MDS genetics and biology and Director of the Edward P. Evans Center for MDS at Washington University (WU). An advisory committee consisting of basic science and clinical/translational MDS experts and pathologists will provide scientific and career advice. The applicant's laboratory is well equipped for these studies, and WU provides a rich environment for training and development as access to core facilities, scientific resources, and clinical samples is exceptional. The experiments outlined in this application aim to clarify the distinct roles of different U2AF1 mutants in MDS pathogenesis, as highly recurrent heterozygous mutations in splicing factor genes (e.g., U2AF1) occur in over half of MDS patients. Hotspot mutations in U2AF1 (encoding U2AF1S34 and U2AF1Q157 mutants) are associated with different clinical features, outcomes, dysregulated RNA splicing, and co-occurring gene mutations in patients with MDS. For example, truncating mutations in ASXL1 cooccur more frequently with U2AF1Q157 than with U2AF1S34 mutations in MDS patients. The candidate has observed U2af1S34F/+ and U2af1Q157R/+ conditional knock-in mice develop different hematopoietic phenotypes, including cytopenias, and have distinct gene expression patterns and aberrant RNA splicing in hematopoietic stem and progenitor cells (HSPC). This proposal aims to understand how the distinct molecular perturbations induced by U2AF1S34F and U2AF1Q157R mutants contribute to the divergent hematopoietic phenotypes observed in MDS patients by determining: (1) how activation of MYC and mTORC1 pathways leads to HSPC dysfunction and multilineage cytopenias in U2af1S34F/+ mice and whether U2AF1S34F-specific splicing alterations result in activation of these pathways, and (2) how mutant ASXL1 and U2AF1Q157 associated histone modification and RNA splicing aberrancies selectively cooperate in MDS pathogenesis. Deciphering the role of MYC and mTORC1 activation will allow these models to be used to test pathway-specific therapeutic strategies to alter cytopenias, and identification of cooperation between ASXL1 and U2AF1 mutations in vivo may reveal novel mechanisms by which RNA splicing and histone modifications synergize in MDS. In sum, the proposed studies and training environment will facilitate the candidate's success in becoming an independent investigator.