A DNA ligase required for active DNA demethylation and genomic imprinting in Arabidopsis
Dear Editor,Active DNA demethylation plays crucial roles in the regulation of gene expression and gene imprinting.In plants,active DNA demethylation is initiated by the ROS1/DME family of 5-methylcytosine-specific DNA glycosylases via a base excision repair mechanism ”1,2”.ROS1 and DME are bifunctional DNA glycosylases that excise the 5-methylcytosine base and then cleave the DNA backbone at the abasic site,resulting in a gap with a 3” phosphate or 3” dRP (3” α,β-unsaturated aldehyde) terminus.The DNA phosphatase ZDP and the apurinic/ apyrimidinic endonuclease APE1L process the 3” phosphate and 3” dRP termini,respectively,to generate a 3” OH group so that downstream polymerases and ligases can fill in the gap with an unmethylated cytosine ”3,4”.
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The work was supported by US National Institutes of Health Grants R01GM070795 and R01GM059138 to J-K Z,and by the Chinese Academy of Sciences and by Peking-Tsinghua Center for Life Science.
2015-07-10(万方平台首次上网日期,不代表论文的发表时间)
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