Protein arginine methyltransferases and transcriptionally active chromosomal domains

真核生物基因组被组织成多个区域，这些区域可以包含一个或多个基因。一些结构域包含表达的基因，而另一些结构域则使基因沉默。这个研究领域被称为表观遗传学，研究的是不依赖于DNA序列变化的基因的组织和表达。在表观遗传学研究中获得的知识有助于理解动物的免疫力。三十多年来，我的研究小组一直专注于组蛋白的研究，组蛋白在基因表达的表观遗传调控中发挥着关键作用。组蛋白与DNA结合，形成一种叫做核小体的结构。核小体由一段DNA连接在一起，形成染色质。组蛋白修饰在基因的组织和表达中起着关键作用，它在表达基因和沉默基因染色质上起着不同的作用。我的研究使用了产蛋鸡的红细胞来表征表达基因的组织。我的研究小组发现了一种从沉默基因染色质中分离出表达基因染色质的方法，当结合最先进的DNA测序方法时，我们识别了鸡红细胞中所有包含表达基因的染色质结构域。令人惊讶的是，鸡的红细胞表达了与免疫反应有关的基因。我建议的研究将探索两种称为蛋白质精氨酸甲基转移酶的酶，PRMT1和PRMT5，在维持与表达的基因染色质结构域相关的组蛋白修饰方面的作用。我们认为这两种酶对于维持基因表达所需的染色质组织是必不可少的。我指导的博士生Sanzida Jahan和一名新的博士生将首先使用鸡红细胞染色质免疫沉淀分析确定PRMT1和PRMT5的位置以及两个特定的组蛋白修饰(组蛋白H3在R2(H3R2me2s)二甲基化(对称)和组蛋白H4在R3(H4R3me2a)二甲基化(不对称))。第二个目的是找出PRMT1和5是如何被定向到表达的基因区域的。这两名学生将识别与这些酶相关的蛋白质。在第三个目标中，他们将使用减少或消除PRMT1和PRMT5表达的方法，并确定这些酶的丢失对鸡红细胞中表达的基因染色质组织的影响。我们预计PRMT酶将是氧运输和免疫相关基因表达所必需的。从这项研究和其他表观遗传学研究中获得的新知识将通过预防健康问题对家禽业产生积极影响。

The eukaryotic genome is organized into domains, which can contain one or several genes. Some domains contain expressed genes, while others have silenced genes. This research field called epigenetics is the study of the organization and expression of genes that is not dependent upon changes in the DNA sequence. The knowledge gained in epigenetic research, has aided in understanding animal immunity. For more than three decades, my research group has focused on the study of histones which play a key role in epigenetic regulation of gene expression. Histones bind to DNA forming a structure called the nucleosome. The nucleosomes are strung together by a stretch of DNA to form chromatin. Histone modifications, which are different in expressed gene and silent gene chromatin, play a key role in the organization and expression of genes. My research uses red blood cells from egg-laying chickens to characterize the organization of expressed genes. My research group discovered a method to separate expressed gene chromatin from silent gene chromatin, and when combined with state-of-the-art DNA sequencing methods, we identified all the chromatin domains containing expressed genes in chicken red blood cells. Surprisingly the chicken red blood cell expressed genes involved in the immune response. My proposed research will explore the role of two of the enzymes called protein arginine methyltransferases, PRMT1 and PRMT5, in maintaining the histone modifications associated with the expressed gene chromatin domains. We believe that these two enzymes are essential to maintaining the chromatin organization needed for gene expression. Sanzida Jahan, a PhD trainee under my supervision, and a new PhD trainee will first determine the location of PRMT1 and PRMT5 and two specific histone modifications (histone H3 dimethylated (symmetric) at R2 (H3R2me2s) and histone H4 dimethylated (asymmetric) at R3 (H4R3me2a)) using the chromatin immunoprecipitation assay with chicken red blood cells. The second aim is to find out how PRMT1 and 5 are directed to expressed gene regions. The two students will identify the proteins associated with these enzymes. In the third aim, they will use methods that reduce or eliminate the expression of PRMT1 and PRMT5 and determine the consequences of the loss of these enzymes on the organization of expressed gene chromatin in chicken red blood cells. We expect that PRMT enzymes will be required for the expression of genes involved in oxygen transport and immunity. The new knowledge gained from this and other epigenetic research will positively impact the poultry industry by preventing health problems.