Project 4: Dynamics of X chromosome inactivation

小鼠内细胞团及其衍生的胚胎干细胞含有两个活性X 染色体。类似地，核重新编程重置X染色体失活状态(XCI) 小鼠诱导的多能干细胞(IPS)，也转录它们的两条X染色体。然而， 剂量补偿在人多能干细胞中的适当地位仍有待澄清。作为 在小鼠ES细胞中传播多能性状态的转录网络已被紧密连接到 X染色体失活的调控，将对确定这些基因是否具有实质性意义 在人类多能干细胞中，调控过程也是紧密耦合的。此外，许多疾病 由X连锁基因突变所致。因为将重新编程的单元用于 在体外模拟这些条件，了解剂量的状态将是至关重要的 在人类IPS细胞及其分化的衍生物中的补偿。在这里，我们建议将 重新编程、干细胞和基因组方法以了解非活性X的行为 染色体在人IPS细胞的产生、维持和分化过程中的作用。我们的具体目标 目标是： 目的1)确定雌性IPS细胞是否遗传体细胞失活的X染色体 以确定它们在长期过程中保持这种不活跃的X的稳定性 文化。 目的2)确定X染色体失活的细胞学特征的丧失是否伴随 通过X染色体上DNA甲基化、染色质结构和转录沉默的松弛。 目的3)确定导致X染色体不稳定的特定培养条件 我们已经观察到并确定了允许适当维护X的培养条件 全染色体异染色质。 相关性(请参阅说明)： 人类多能干细胞是更好地理解和治疗大多数 退行性疾病。然而，如果我们要将这些干细胞用于医疗应用，我们必须 了解基本属性。我们建议观察X染色体失活的过程 在人类iPS细胞中。了解X染色体生物学对于在建模中使用IPS细胞是必不可少的 DlsaasRS nau.sfil MV X chrnmnsmfi miitatinn.g

The mouse inner cell mass (ICM) and the embryonic stem (ES) cells derived from it contain two active X chromosomes. Similarly, nuclear reprogramming resets the state of X chromosome inactivation (XCI) in mouse induced pluripotent stem (IPS) cells, which also transcribe both of their X chromosomes. However, the proper status of dosage compensation in human pluripotent stem cells remains to be clarified. As the transcriptional networks that propagates the pluripotent state in mouse ES cells has been tightly linked to the regulation of X chromosome inactivation, it will be of substantial interest to determine whether these gene regulatory processes are also tightly coupled within human pluripotent stem cells. In addition, many diseases result from mutations in X-linked genes. As there is substantial interest in using reprogrammed cells for modeling these conditions in vitro, it will be critically important to understand the state of dosage compensation in both human IPS cells and their differentiated derivatives. Here we propose to combine reprogramming, stem cell and genomic approaches to understand the behavior of the inactive X chromosome during the generation, maintenance and differentiation of human IPS cells. Our specific aims are to: Aim 1) To determine whether female IPS cells inherit the inactive X chromosome of the somatic cells from which they are derived and to determine how stably they maintain this inactive X in the course of long-term culture. Aim 2) To determine whether the loss of cytological hallmarks of X chromosome inactivation is accompanied by X-chromosome-wide relaxation of DNA methylation, chromatin structure and transcriptional silencing. Aim 3) We will determine the specific culture conditions that contribute to instability of X chromosome inactivation that we have observed and identify culture conditions that allow proper maintenance of X chromosome-wide heterochromatin. RELEVANCE (See instructions): Human pluripotent stem cells represent a significant opportuninty to better understand and treatmost any degenertive disease. However, if we are to use these stem cells for medical applications, we must understand the fundemental properties. He we propose to look at the process of X chromosome inactivation in human iPS cells. Understanding X chromosome biology will be essential for the use IPS cells in modeling dlsaasRS nau.sfifl mv X chrnmnsnmfi miitatinn.g