SPECIFICITY OF HISTONE ACETYLTRANSFERASE ENZYMES FROM ARABIDOPSIS THALIANA

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 皮卡德实验室利用遗传学、生物化学和分子生物学技术，研究基因被激活和抑制的方式。我们目前的研究项目集中在基因沉默以及染色质蛋白和小RNA(SiRNAs)在这些表观遗传现象中所起的作用。本课题的研究主要集中在植物上，其中重要的植物是拟南芥。 不活跃的rRNA基因通过染色质修饰而沉默。RRNA基因沉默涉及DNA甲基化和组蛋白修饰的协同变化，我们提出了一个模型，即DNA和组蛋白修饰各自位于彼此的上游，处于自我增强的循环路径中。Pikaard研究小组希望通过使用RNA干扰来抑制靶基因的表达，从而确定参与这一抑制循环的染色质修饰活动。到目前为止，已经在筛选中鉴定出两个组蛋白脱乙酰酶、一个DNA甲基转移酶和几个甲基胞嘧啶结合蛋白。我们正在利用各种遗传、细胞遗传学和生化方法来了解这些染色质修饰活动的作用机制(S)，并了解它们的作用是如何相互交织在一起构成表观遗传的开关

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The Pikaard lab studies the ways genes are activated and repressed, using techniques of genetics, biochemistry and molecular biology. Our current research projects are focused on gene silencing and the role that chromatin proteins and small RNAs (siRNAs) play in these epigenetic phenomena. the research focuses on plants, the important one for this project is Arabidopsis thaliana. Inactive rRNA genes are silenced via chromatin modifications. rRNA gene silencing involves concerted changes in both DNA methylation and histone modification and we have proposed a model whereby DNA and histone modifications are each upstream of one another in a self-reinforcing, circular pathway. The Pikaard group wishes to identify the chromatin modifying activities involved in this repression cycle, using RNA-interference to knock down the expression of targeted genes. Two histone deacetylases, one DNA methyltransferase and several methylcytosine binding proteins have been identified in the screens thus far. We are making use of a variety of genetic, cytogenetic and biochemical approaches in order to understand the mechanism(s) of action of these chromatin modifying activities and to understand how their actions are intertwined to comprise an epigenetic on-off switch