在植物中转录基因沉默可以被多种不同的机制调控。其中，RNA介导的DNA甲基化(RdDM)在调控转座子以及一些重复序列的基因沉默研究方面的研究较为深入，但目前对于不依赖于RdDM调控的基因沉默机制知道的较少。我们利用两个特殊的基因沉默体系，通过筛选基因沉默解除和抑制基因沉默的突变体，解析不依赖于RdDM途径的转录基因沉默机理。通过筛选，我们获得大量的突变体，并克隆了一些新的基因。其中一类基因编码DNA复制核心蛋白，暗示这些基因在DNA复制中对表观遗传信息的传递起重要作用。这一现象也在酵母、动物中广泛存在。我们计划利用这些拟南芥材料，通过各种生化、遗传等分析，阐明在DNA复制过程中，这些蛋白在表观遗传信息传递过程中的作用及其分子机理。这些研究将为深入理解不依赖于RdDM调控的基因沉默机制提供重要的线索。

Transcriptional gene silencing (TGS) is regulated by different mechanisms. Among them, RNA-directed DNA methylation (RdDM) in controlling transposons and non-protein-coding repeat regions has been well studied in plants. However, the molecular mechanism of TGS mediated by the RdDM-independent pathway is barely known. Our previous studies indicated that Arabidopsis mutants defective in DNA replication released TGS of the silenced genes, which is not dependent on RdDM pathway. This is a very popular biological phenomenon that is also found in yeast and animals, but the molecular mechanisms are unknown. We are planning to use two developed TGS systems that are independent on RdDM pathway to isolate more mutants and to clone the corresponding genes. We will use these materials to resolve one key scientific question: What roles of these proteins in inheritance of epigenetic information during DNA replication? Our study will provide more clues for understanding the TGS mechanism mediated by RdDM-independent pathway.