Mechanism of nucleolar dominance in Arabidopsis

描述（由申请人提供）： 核仁显性是一种稳定的表观遗传现象，即亲本的rRNA基因在杂种F1中被转录抑制。杂种细胞中的核仁优势被认为是非杂种细胞控制核糖体基因转录的极端延伸。作为一种表观遗传过程，它是一个有吸引力的模型，有几个原因，最重要的是它是完全可重复的，第二，它是一个普遍的过程，通过广泛的植物和动物发生，最后，调节rRNA基因转录的过程可能在基因组范围内发挥转录作用。Pikaard博士的实验室在研究核仁优势方面拥有丰富的经验，此外，在NSF赞助的与其他实验室联盟的合作中，Pikaard实验室现在正在完成一个为期两年的项目，敲除拟南芥中所有已知的染色质修饰基因。这大大扩展了我开始研究这个过程的工具。我的具体目标是首先确定参与建立核仁优势过程的基因。我已经开始筛选我们收集的敲除基因，并创造新的突变体，破坏它们诱导核仁优势的能力。有了这些突变体在手，我将能够研究这些基因之间的物理和遗传相互作用。最后，考虑到快速 随着我们对染色质结构分析的进展，我将能够研究染色质修饰如何驱动转录沉默。

DESCRIPTION (provided by applicant): Nucleolar dominance is a stable epigenetic phenomenon by which the rRNA genes of one parent are transcriptionally repressed in an F1 hybrid. Nucleolar dominance in hybrid cells is thought to be an extreme extension by which the non-hybrid cell may control the extant of ribosomal gene transcription. As an epigenetic process it is an attractive model for several reasons, most importantly it is completely reproducible, second, it is a general process that occurs through a broad range of plants and animals, finally, the processes that regulate transcription of rRNA genes are likely to play a transcriptional role genome wide. Dr. Pikaard's lab has extensive experience in investigating nucleolar dominance, additionally, in an NSF sponsored collaboration with a consortium of other labs, the Pikaard lab is now completing a two-year project in knocking out all of the known chromatin modifying genes in Arabidopsis. This greatly expands the tools by which I can begin studying this process. My specific aims are to first identify genes that are involved in the process of establishing nucleolar dominance. I have started screening our collection of knockouts as well as creating novel mutants disrupted in their ability to induce nucleolar dominance. With these mutants in hand I will then be able to investigate the physical and genetic interactions between these genes. Finally, given the rapid advances in our analysis of chromatin structure, I will be able to examine how chromatin modification drives transcriptional silencing.