DNA甲基化修饰是一种重要的表观遗传学标志，在维持基因组稳定、调控基因表达、沉默转座子和调节生物体发育等过程中发挥着重要作用。基因组DNA的甲基化水平和分布主要由DNA甲基化和去甲基化两个途径协同调控。已有的研究表明植物中DNA的主动去甲基化是通过ROS1/DME家族介导的碱基切除修复机制来实现的。我们前期的研究发现IDM1和IDM2在调控DNA主动去甲基化方面具有重要作用。本项目希望通过纯化IDM1蛋白复合体并利用液质联用质谱技术鉴定新的与IDM1相互作用的蛋白，进一步研究DNA主动去甲基化的调控机制。前期工作中，我们已经找到两个新的IDM1相互作用蛋白IDAP1和IDAP2，并成功分离鉴定了相关的功能缺失突变体。我们将采用高通量测序、生化和细胞生物学的手段来分析这两个蛋白的功能。该项目的研究成果对于阐明ROS1介导的 DNA主动去甲基化的调控机制有重大意义。

DNA methylation is an important epigenetic marker and plays important roles in transposon silencing, gene expression, gene imprinting, and many other vital processes. DNA methylation levels in plants are dynamically regulated by DNA methylation and active DNA demethylation in response to developmental and environmental changes. In Arabidopsis thaliana, active DNA demethylation is carried out by the ROS1 family of 5-methylcytosine-specific DNA glycosylases via a base excision repair mechanism. Recently, the histone acetyltransferase IDM1 was shown to be required for the recruitment of ROS1 to some of its target loci. However, little is known about the locus-specific targeting of IDM1 in plants. To better understand the mechanism of IDM1 targeting in active DNA demethylation, we purified the protein complex associated with IDM1. We have identified two novel components, IDAP1 and IDAP2, and isolated their T-DNA knock out mutants. Functions of IDAP1 and IDAP2 will be investigated through high throughput sequencing and methods in biochemistry and molecular biology. Our findings will provide novel insights into the molecular mechanisms of ROS1-mediated active DNA demethylation in plants.