Gene regulation for stem cell differentiation

摘要 UTX是大脑、心脏和骨骼发育所需的染色质修饰剂。为了促进基因 活化，UTX从组蛋白H3中的甲基化赖氨酸27中去除甲基化（H3 K27甲基化）， 促进H3 K27乙酰化、H3 K4甲基化和开放染色质结构。在人类中，UTX突变是 与发育综合征和许多儿童和成人的脑癌，血癌， 膀胱、食道、肾脏和乳房。虽然UTX的重要性已经确立，但它如何针对和 调控基因仍不清楚。特别是，相互矛盾的发现提出了一个问题， UTX的修饰活性对于干细胞中的发育基因调控是重要的。这一知识空白 限制了我们对与UTX功能障碍相关的发育缺陷和癌症的病因学的理解 或H3 K27修饰。 我们的长期目标是通过确定UTX如何调节染色质结构来填补这一知识空白 和基因表达来控制干细胞的功能。我们的初步研究确定了UTX的蛋白质网络 这对于人类多能干细胞向神经谱系的分化是重要的。在这个网络中， DNA损伤反应因子在调控基因表达中起着非经典的作用。我们的核心假设 这种以UTX为中心的网络促进了干细胞分化过程中染色质的变化和转录激活， 分化为了验证这一假设，我们计划鉴定UTX的染色质调节活性， 转录，检查该网络中DNA损伤反应因子的非经典功能， 阐明执行基因表达编程的下游效应子的作用。我们的方法将 利用新的UTX驱动的蛋白质网络的概念创新和技术优势， 将Cas9-CRISPR结合用于结构-功能研究、基因组学分析和人类基因组学研究的创新 皮质类器官模型如果成功，我们希望我们的发现对表观遗传学有广泛的影响。 调节人类干细胞的发育和癌症。

ABSTRACT UTX is a chromatin modifier required for the development of brain, heart, and bone. To facilitate gene activation, UTX removes methylation from methylated lysine 27 in histone H3 (H3K27 methylation) and promotes H3K27 acetylation, H3K4 methylation, and open chromatin structure. In humans, UTX mutations are causally linked to a developmental syndrome and to many childhood and adult cancers of the brain, blood, bladder, esophagus, kidney, and breast. Although the importance of UTX is established, how it targets and regulates genes remains unclear. In particular, contradictory findings raise the question about which chromatin modifying activity of UTX is important for developmental gene regulation in stem cells. This knowledge gap limits our understanding of the etiology of developmental defects and cancers associated with UTX dysfunction or H3K27 modifications. Our long-term goal is to fill this knowledge gap by determining how UTX regulates chromatin structure and gene expression to govern stem cell functions. Our preliminary studies identified a protein network of UTX that is important for the differentiation of human pluripotent stem cells to the neural lineage. In this network, DNA damage response factors play a noncanonical role in regulating gene expression. Our central hypothesis is that this UTX-centric network facilitates chromatin changes and transcriptional activation during stem cell differentiation. To test this hypothesis, we plan to identify the chromatin-regulatory activity of UTX that affects transcription, examine the noncanonical function of DNA damage response factors in this network, and elucidate the role of a downstream effector that executes gene expression programming. Our approaches will take advantage of the conceptual innovation about a new UTX-driven protein network and the technological innovation of combining Cas9-CRISPR for structure–function studies, genomics assays, and the human cortical organoid model. If successful, we expect our findings to have wide implications on epigenetic regulation of human stem cells in development and cancer.