Functional Analysis of Epigenetic Complexes

摘要：为了人类的正常发育，受精卵必须以一种 生成一个在正确的位置具有正确的器官和附件的身体。其中很大一部分 是由主调控基因的适当的时间和空间调节决定的 引导构成器官和附件的分化细胞的形成。一个关键方面 在这一发育过程中，保持主控调控基因的能力受到抑制 在其表达可能导致不适当的细胞行为的细胞中的状态。错误表达的 即使是一个单一的主要调控基因，比如那些编码在Hox基因座上的基因，也可以导致一个细胞 行为方式与其身体位置和组织类型不相容。复式梳子- 基因组(PcG)在很大程度上负责维持这种抑制，基于 在过去的70年里进行了密集的研究。维持基因的活跃表达模式是 对发展同样至关重要。一组维持激活的基因，称为三胸- 通过抑制PcG突变的能力而被分离出来。此应用程序 描述了我们在理解编码的蛋白质的功能方面的继续工作 由PcG和trxG基因决定。这些蛋白质形成几个复合体。PcG络合物Prc1 和PrC2都是含有几个PcG基因产物的大复合体。PRC1是主要的 聚梳组中的抑制引擎，并已知与染色质相互作用， 将基因包装在细胞核中的结构。染色质结构可以呈现 封闭的DNA不能被激活因子获得。一个突出的假设是，压抑可以 是通过产生高度包装的DNA而产生的，这种DNA不再能够转录和 表达。我们描述了调查PRC1使用的各种机制的方法 生成打包的染色质。PRC1和PRC2一起工作，产生压制。PRC2 甲基化核小体，染色质的主要包装单位，残基H3K27，一个主题 在众多实验室和公司进行密集研究。我们打算提供新颖的 通过探索与甲基化无关的PRC2抑制活性来获得信息。我们 还将描述参与基因调控的一种单独蛋白质的PrC2甲基化的特征， ElonginA.最后，我们将描述编码的两种不同的核小体重塑活动 通过trxG基因，哺乳动物的SWI/SNF(BAF)复合体和哺乳动物的CHD7。我们会 探索SWI/SNF亚基与染色质组织活动粘附素之间的相互作用， 并确定这些相互作用如何影响染色质中的远程相互作用。我们会 研究一种名为HERVH的lncRNA在靶向CHD7活性中的作用。

Abstract: For humans to develop properly, the fertilized egg must divide in a manner that generates a body that has the correct organs and appendages in the correct places. Much of this is determined by the proper temporal and spatial regulation of master regulatory genes that guide formation of the differentiated cells that make up organs and appendages. A key aspect of this developmental process is the ability to maintain master regulatory genes in a repressed state in cells where their expression might cause inappropriate cell behavior. Mis-expression of even a single master regulatory gene, such as those encoded in the HOX loci, can result in a cell behaving in a manner incompatible with its body location and tissue type. The Polycomb- Group (PcG) group of genes is largely responsible for maintaining this repression, based upon intensive study over the past 70 years. Maintaining active expression patterns for genes is equally critical for development. A set of genes that maintains activation, called the trithorax- Group (trxG), was isolated via their ability to suppress PcG mutations. This application describes the continuation of our work on understanding the function of the proteins encoded by the PcG and trxG genes. These proteins form several complexes. The PcG complexes PRC1 and PRC2 are each large complexes that contain several PcG gene products. PRC1 is the main `engine' of repression in the Polycomb-Group and is known to interact with chromatin, the structure that packages genes in the nucleus of cells. Chromatin structure can render the enclosed DNA inaccessible to activating factors. A prominent hypothesis is that repression can be generated by generating highly packaged DNA that is no longer able to be transcribed and expressed. We describe approaches to investigate the various mechanisms used by PRC1 to generate packaged chromatin. PRC1 works together with PRC2 to generate repression. PRC2 methylates nucleosomes, the primary packaging unit of chromatin, on residue H3K27, a topic of intensive study in numerous laboratories and companies. We intend to provide novel information by exploring repressive activities of PRC2 that are unrelated to methylation. We will also characterize methylation by PRC2 of a separate protein involved in gene regulation, ElonginA. Finally, we will characterize two separate nucleosome remodeling activities encoded by trxG genes, the mammalian SWI/SNF (BAF) complex and mammalian CHD7. We will explore interactions between SWI/SNF subunits and cohesin, a chromatin organizing activity, and determine how those interactions impact long range interactions in chromatin. We will examine the role for a lncRNA called HERVH in targeting CHD7 activity.