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。促进基因 激活，UTX去除组蛋白H3中甲基化赖氨酸27的甲基化(H3K27甲基化)和 促进H3K27乙酰化、H3K4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。尽管UTX的重要性已经确定，但它如何瞄准和 对基因的调控尚不清楚。特别是，相互矛盾的发现提出了关于哪种染色质的问题 修饰UTX的活性对干细胞的发育基因调控具有重要意义。这种知识鸿沟 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的了解 或H3K27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 以及控制干细胞功能的基因表达。我们的初步研究确定了UTX的一个蛋白质网络 这对人类多能干细胞向神经系分化非常重要。在这个网络中， DNA损伤反应因子在基因表达调控中起着非规范的作用。我们的中心假设 是这个以UTX为中心的网络促进了干细胞过程中染色质的变化和转录激活 差异化。为了验证这一假设，我们计划确定UTX的染色质调节活性，以影响 转录，检测DNA损伤反应因子在这个网络中的非规范功能，以及 阐明执行基因表达编程的下游效应器的作用。我们的方法将 利用UTX驱动的新蛋白质网络的概念创新和技术 结合Cas9-CRISPR用于结构-功能研究、基因组分析和人类的创新 皮质器官模型。如果成功，我们预计我们的发现将对表观遗传学产生广泛的影响 人类干细胞在发育和癌症中的调控。

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.