A novel protein complex that regulates active DNA demethylation in Arabidopsis.

Pan Liu, Wen-Feng Nie, Xiansong Xiong, Yuhua Wang, Yuwei Jiang, Pei Huang, Xueqiang Lin, Guochen Qin, Huan Huang, Qingfeng Niu, Jiamu Du, Zhaobo Lang, Rosa Lozano-Duran, Jian-Kang Zhu

Journal of integrative plant biology 2021 Apr

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Active DNA demethylation is critical for altering DNA methylation patterns and regulating gene expression. The 5-methylcytosine DNA glycosylase/lyase ROS1 initiates a base-excision repair pathway for active DNA demethylation and is required for the prevention of DNA hypermethylation at 1 000s of genomic regions in Arabidopsis. How ROS1 is regulated and targeted to specific genomic regions is not well understood. Here, we report the discovery of an Arabidopsis protein complex that contains ROS1, regulates ROS1 gene expression, and likely targets the ROS1 protein to specific genomic regions. ROS1 physically interacts with a WD40 domain protein (RWD40), which in turn interacts with a methyl-DNA binding protein (RMB1) as well as with a zinc finger and homeobox domain protein (RHD1). RMB1 binds to DNA that is methylated in any sequence context, and this binding is necessary for its function in vivo. Loss-of-function mutations in RWD40, RMB1, or RHD1 cause DNA hypermethylation at several tested genomic regions independently of the known ROS1 regulator IDM1. Because the hypermethylated genomic regions include the DNA methylation monitoring sequence in the ROS1 promoter, plants mutated in RWD40, RMB1, or RHD1 show increased ROS1 expression. Importantly, ROS1 binding to the ROS1 promoter requires RWD40, RMB1, and RHD1, suggesting that this complex dictates ROS1 targeting to this locus. Our results demonstrate that ROS1 forms a protein complex with RWD40, RMB1, and RHD1, and that this novel complex regulates active DNA demethylation at several endogenous loci in Arabidopsis. © 2020 The Authors. Journal of Integrative Plant Biology Published by John Wiley & Sons Australia, Ltd on behalf of Institute of Botany, Chinese Academy of Sciences.

Citation

Pan Liu, Wen-Feng Nie, Xiansong Xiong, Yuhua Wang, Yuwei Jiang, Pei Huang, Xueqiang Lin, Guochen Qin, Huan Huang, Qingfeng Niu, Jiamu Du, Zhaobo Lang, Rosa Lozano-Duran, Jian-Kang Zhu. A novel protein complex that regulates active DNA demethylation in Arabidopsis. Journal of integrative plant biology. 2021 Apr;63(4):772-786