Exploring novel regulatory mechanisms underlying enhancer activation and cell fate transition

探索增强子激活和细胞命运转变的新调控机制

• 批准号: 9891069
• 负责人: Kaixiang Cao
• 金额: $ 10.16万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-03-11 至 2020-09-07
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9891069
• 关键词: 3-Dimensional; Animals; Architecture; Award; Binding; Binding Proteins; Biochemistry; Bioinformatics; Biological Assay; Biology; Bruck-de Lange syndrome; CRISPR screen; Cell Differentiation process; Cell Maintenance; Cells; Chromatin; Chromatin Structure; Data; Deposition; Development; Disease; Dose; Down-Regulation; ES Cell Line; Educational workshop; Embryonic Development; Enhancers; Ensure; Environment; Enzymes; Epigenetic Process; Equilibrium; Family; Gene Expression; Genes; Genetic Transcription; Genome; Genomic approach; Goals; Grant; Higher Order Chromatin Structure; Histone H3; Human; Instruction; KDM1A gene; Kabuki Make-Up Syndrome; Knock-out; Lead; Leadership; Lysine; Malignant Neoplasms; Mentors; Methylation; Modeling; Molecular; Mutation; Names; Output; Pathogenesis; Pathology; Pathway interactions; Phase; Play; Pluripotent Stem Cells; Postdoctoral Fellow; Process; Proteomics; Regulation; Research; Role; SET Domain; Stem Cell Factor; Testing; Thalassemia; Training; Transcriptional Regulation; Universities; Writing; base; cancer type; career; career development; chromosome conformation capture; clinical application; course development; developmental disease; driver mutation; embryonic stem cell; experience; genetic corepressor; genome wide screen; genome-wide; graduate student; high throughput screening; histone methyltransferase; human disease; inhibitor/antagonist; innovation; insight; loss of function; loss of function mutation; medical schools; member; new therapeutic target; novel; pluripotency; programs; protein complex; recruit; skills; stem cell biology; stem cell differentiation; stem cells; targeted treatment; therapy development; transcription factor; transcriptome

Project Summary/Abstract Misregulation of enhancer activity leads to various developmental disorders including thalassemia, Cornelia de Lange syndrome, and Kabuki syndrome. The major enhancer regulator Mll4 belongs to the family of the Su(var)3- 9, Enhancer-of-zeste, Trithorax (SET) domain containing histone methyltransferases named COMplex of Proteins ASsociated with Set1 (COMPASS), which places methylation marks at lysine 4 of histone H3 (H3K4). Mll4 is essential for mammalian development and its heterozygous loss-of-function mutations lead to various human diseases including Kabuki syndrome and cancer. I recently demonstrated that Mll4 is the major enzyme depositing mono-methylation at H3K4 (H3K4me1), an enhancer-decorating epigenetic mark whose function remains elusive. Moreover, I have defined catalytic activity dependent and independent functions of Mll4 in enhancer modulation and stem cell differentiation, and have unveiled an antagonism between enhancer-binding epigenetic machineries in transcriptional control that could underlie the developmental consequences of the heterozygous loss-of-function mutations of Mll4 in human disease. Based on these findings, I hypothesize that Mll4 cooperates with key transcription factors and epigenetic modifiers to modulate enhancer activity, chromatin structure, and transcriptional outputs during stem cell maintenance and differentiation. The studies proposed here aim to elucidate the molecular mechanisms of enhancer regulation, and to provide insights for developing novel therapies targeting diseases driven by the loss of function of epigenetic modifiers. Specifically, the outlined research will 1) elucidate how epigenetic marks impact enhancer functions and cell fate transition; 2) determine the role of higher order chromatin structure in stem cell maintenance and differentiation; 3) identify novel factors and pathways involved in modulating enhancer activity and determining cell fate. To achieve the long-term career goal of defining the epigenetic mechanisms underlying mammalian development and disease, I will acquire training in biochemistry, proteomics, bioinformatics, stem cell biology, and genome-wide screening during the mentored phase of this application. Moreover, I will participate in grant writing workshops and career development courses to strengthen my skills in writing and leadership. With the acquired training, I will be well- prepared for the task of delineating the machineries and mechanisms in modulating gene expression, chromatin structure, and cell fate determination in the independent R00 phase. In summary, the K99/R00 award, together with the experiences that I have garnered as a graduate student and postdoc, the guidance from the mentors and collaborators, and the superb research environment at Northwestern University's Feinberg School of Medicine, will ensure a successful transition for me to continue my independent scientific career in the field of stem cell biology and epigenetics.

项目摘要/摘要 增强子活性的错误调节会导致各种发育障碍，包括地中海贫血、角膜病变 兰格综合症和歌舞伎综合症。主要的增强子调节因子MLL4属于SU(Var)3家族- 9，含有组蛋白甲基转移酶的三胸胸腺(SET)结构域，名为 与Set1(COMPASS)相关的蛋白质，它将甲基化标记放在组蛋白H3(H3K4)的赖氨酸4上。 MLL4是哺乳动物发育所必需的，它的杂合性功能缺失突变导致多种 包括歌舞伎综合症和癌症在内的人类疾病。我最近证明了MLL4是主要的酶 在H3K4(H3K4me1)上沉积单甲基化，这是一种增强子修饰的表观遗传标记，其功能 仍然难以捉摸。此外，我还定义了MLL4的催化活性依赖函数和独立函数。 增强子调控和干细胞分化，并揭示了增强子结合之间的拮抗作用 转录控制中的表观遗传机制，可能是 人类疾病中MLL4杂合性功能丧失突变。基于这些发现，我假设 MLL4与关键转录因子和表观遗传修饰物合作，调节增强子活性，染色质 结构，以及干细胞维持和分化过程中的转录输出。这项研究建议 本文旨在阐明增强子调控的分子机制，为进一步研究增强子的调控机制提供参考。 针对表观遗传修饰物功能丧失所驱动的疾病的新疗法。具体地说，概述 研究将1)阐明表观遗传标记如何影响增强子功能和细胞命运转变；2)确定 高阶染色质结构在干细胞维持和分化中的作用；3)识别新的因子 以及参与调节增强子活性和决定细胞命运的途径。为了实现长期的职业生涯 确定哺乳动物发育和疾病背后的表观遗传机制的目标，我将获得 生物化学、蛋白质组学、生物信息学、干细胞生物学和全基因组筛选方面的培训 此应用程序的指导阶段。此外，我还将参加助学金撰写工作坊和职业生涯 发展课程，以加强我的写作和领导能力。经过培训后，我会很好的- 为描述调控基因表达的机制和机制的任务做好准备 结构，以及在独立的R00阶段细胞命运的决定。总而言之，K99/R00奖，一起 凭借我作为研究生和博士后积累的经验，导师们的指导 和合作者，以及西北大学范伯格学院一流的研究环境 医学，将确保我成功过渡，继续我的独立科学生涯 干细胞生物学和表观遗传学。