Epigenetic Encoding and Reprogramming in C. elegans

描述（由申请人提供）：定义分化细胞类型的转录组受到表观遗传过程施加于基因组的染色质结构的强烈影响。这种结构信息在构建组织所需的细胞分裂分化过程中变得遗传稳定或程序化。当试图逆转或重编程分化细胞到多能干细胞状态时所遇到的困难揭示了这些信息的稳定性。目前的策略，如诱导多能干细胞（iPS）技术是惊人的，但效率低下，所获得的细胞质量尚不清楚。这些问题是由于这些重编程技术中涉及的不受控制的过程的随机性。相比之下，高度分化的配子基因组在受精卵中相遇时，会非常有效和准确地重新编程，从而产生全能的表观基因组。重要的是，有表观遗传信息到达配子，在亲本种系中编码，这不是重编程的目标。这一信息可能有助于合子的全能性和生殖系的持续不朽。三个问题是理解这些过程的核心：1)表观遗传信息是如何通过配子在受精卵中重新编程遗传的？2)特定信息如何避免这种命运，并在几代人之间保持稳定？3)如何区分这些不同命运的适当目标？在这个项目中，我们将利用线虫的遗传和表观遗传工具来确定合子重编程的目标。我们将进一步确定参与亲代编程和合子重编程机制的表观遗传修饰因子。我们将测试和调整协议，将分析扩展到全基因组方法。长期目标是利用这些实验获得的信息来确定将编程和重编程机制引导到基因组中适当位置的机制。这将最终指导治疗中断或操纵导致遗传性表观遗传疾病状态的机制，并确定适当指导体外重编程的策略，以有效地实现与治疗安全相容的状态。

DESCRIPTION (provided by applicant): The transcriptome that defines a differentiated cell type is strongly influenced by the chromatin structure imposed on the genome by epigenetic processes. This structural information becomes heritably stabilized, or programmed, as differentiation proceeds through the cell divisions required to build a tissue. The stability of ths information is revealed by the difficulties encountered when trying to reverse, or reprogram, a differentiated cell into a pluripotent stem cell state. Current strategies, such as induced pluripotent stem cell (iPS) technologies are amazing but inefficient, and the quality of the cells obtained is unclear. These problems are due the stochastic nature of uncontrolled processes involved in these reprogramming techniques. In contrast, the highly differentiated gamete genomes are quite efficiently and accurately reprogrammed when they meet in the zygote, creating a totipotent epigenome. Importantly, there is epigenetic information that arrives in the gametes, encoded in the parental germ line, which is not targeted for reprogramming. This information presumably contributes to the totipotency of the zygote and the continued immortality of the germline. Three questions are central to understanding these processes: 1) How is epigenetic information inherited through the gametes reprogrammed in the zygote?; 2) How does specific information avoid this fate to remain stable through generations?; and 3) How is discrimination between the appropriate targets for these different fates achieved? In this project, we will take advantage of the genetic and epigenetic tools available in C. elegans to identify targets of zygotic reprogramming. We will further identify epigenetic modifiers that participate in the parental programming and zygotic reprogramming mechanisms. We will test and adapt protocols to expand the analyses to a genome-wide approach. The longer-term goal is to use the information obtained by these experiments to identify the mechanisms that direct the programming and reprogramming machinery to the appropriate sites in the genome. This will ultimately guide therapies to interrupt or manipulate mechanisms that contribute to heritable epigenetic disease states, and identify strategies that will appropriately guide in vitro reprogramming to efficiently achieve a state compatible with therapeutic safety.