Regulation mechanism of chromatin structure in the maintenance of plant genome stability

Abstract

Genome stability is always challenged by exogenous and endogenous stresses. As a sessile organism, plants are surrounded by various environmental stresses that induce DNA damage and inhibit plant growth. Thus, the maintenance of genome stability has an important role in the the growth and development of plants. In eukaryotes, DNA is wrapped with histones to form chromatin that is high-ordered structure in nuclei. The chromatin structure dramatically changes in accordance with DNA damage. However, little is known about the mechanism controlling the chromatin structure in response to DNA damage in plants. In this study, I investigated the regulation mechanism of chromatin structure during DNA damage response of Arabidopsis, mainly using live cell imaging techniques. My imaging analysis showed that chromatin remodeling factor RAD54 is required for the change of chromatin structure with DNA damages. I also found that RAD54 forms subnuclear foci (named RAD54 foci) in response to DNA damage. Additionally, I identified histone demethylase LDL1 as novel interacting factor of RAD54, using interactome analysis based on co-immunoprecipitation and LC-MS/MS analysis. My biochemical and imaging analysis showed that LDL1 regulates the dynamics of RAD54 at damaged sites through the demethylation of H3K4me2.