Determinants of Self-Renewal, Differentiation, and Reprogramming of hESCs

了解人类胚胎干细胞如何 无限增殖但仍保持分化为任何细胞类型的能力是链接的主题 这项提案的三个单独项目。项目1将确定人类新的组蛋白修饰 ES细胞使用一种新的质谱学技术，允许前所未有的能力来识别和 绘制翻译后蛋白质修饰图。人类胚胎干细胞中的组蛋白修饰将被识别 在全球范围内，在启动子上，在关键的多能性因子直接调控的特定基因上。我们会 还要检验组蛋白H3变体在建立长期表观遗传记忆中的作用。这些 研究将确定在多能细胞中是否存在新的组蛋白密码，并确定如何 组蛋白修饰在分化过程中动态变化。项目2检查关键事件 发生在人类ES细胞承诺退出多能性状态的时间窗口中 骨形态发生蛋白诱导分化。该项目将提供对以下过程的更多了解 承诺人类胚胎干细胞退出多能状态，并指定不同的谱系结果。项目3 将识别ES细胞特异性基因的组合，这些基因可以将分化的细胞重新编程为 多能状态。我们之前已经报道过，当髓系细胞与人类ES细胞融合时， 髓核被重新编程为ES细胞状态，表明ES细胞中的交易因子 足以调解核重新编程。我们的初步结果表明，过度表达 人类ES细胞富含基因的组合可以对髓系细胞进行重新编程，该项目将 优化这个重新编程。这些项目的结合将提供更多的 对多能状态和细胞离开或返回的基本过程的理解 那个州。这样的理解对移植和再生医学将是重要的。 人类胚胎干细胞是特殊的，因为它们可以无限生长，并能产生 所有其他类型的细胞。在这里，我们将尝试理解为什么人类胚胎干细胞具有如此非凡的 发展潜力，并创造条件将潜力更有限的细胞转化为胚胎干细胞 手机。这种重新编程对移植和再生医学有影响。

Understanding how human embryonic stem (ES) cells can proliferate without limit and yet retain the ability to differentiate to any cell type is the theme that links the three individual projects of this proposal. Project 1 will identify novel histone modifications in human ES cells using a new mass spectrometry technique that allows an unprecedented ability to identify and map posttranslational protein modifications. Histone modifications in human ES cells will be identified globally, at promoters, and at select genes directly regulated by critical pluripotency factors. We will also examine the role of histone H3 variants in establishing long-term epigenetic memory. These studies will determine whether there is a novel histone code in pluripotent cells and determine how histone modifications change dynamically during differentiation. Project 2 examines the critical events that occur in the window of time during which human ES cells commit to exit the pluripotent state upon BMP-induced differentiation. This project will provide an increased understanding of the processes that commit human ES cells to exit the pluripotent state and specify different lineage outcomes. Project 3 will identify combinations of ES cell-specific genes that can reprogram differentiated cells to a pluripotent state. We have previously reported that when myeloid cells are fused with human ES cells, the myeloid nucleus is reprogrammed to an ES cell state, indicating that transacting factors in ES cells are sufficient to mediate nuclear reprogramming. Our preliminary results suggest that over expressing combinations of human ES cell-enriched genes can reprogram myeloid cells, and this project will optimize this reprogramming. The combination of these projects will provide an increased understanding of the pluripotent state and the basic processes by which a cell can leave or return to that state. Such an understanding will be important to transplantation and regenerative medicine. Lay Description: Human ES cells are special because they can grow without limit and can give rise to all other cell types. Here we will try to understand why human ES cells have this remarkable developmental potential, and develop conditions to convert a cell with a more limited potential to an ES cell. Such reprogramming has implications for transplantation and regenerative medicine.