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，在F1中，亲本的rRNA基因在转录水平上受到抑制。杂交细胞的核仁优势被认为是非杂交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，原因有几个，最重要的是它是完全可重复性的，其次，它是一个在广泛的动植物中发生的一般过程，最后，调节rRNA基因转录的过程可能在全基因组范围内发挥转录作用。皮卡德博士的实验室在研究核仁显性方面拥有丰富的经验，此外，在美国国家科学基金会与其他实验室联盟的合作下，皮卡德的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。这极大地扩展了我开始研究这一过程的工具。我的具体目标是首先确定在建立核仁显性的过程中涉及的基因。我已经开始筛选我们收集的基因敲除基因，以及创造新的突变体，这些突变体破坏了它们诱导核仁显性的能力。有了这些突变体，我将能够研究这些基因之间的物理和遗传相互作用。最后，考虑到快速的 随着染色质结构分析的进展，我将能够研究染色质修饰是如何驱动转录沉默的。

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.