GSE59712
MethlyC-Seq of Col-0 WT, idm3-3 and mbd7-2 (CS876032) mutant
In eukaryotes, heterochromatin is characterized by numerous epigenetic marks, including DNA methylation. Spreading of these marks into nearby active genes must be avoided in order to maintain appropriate gene expression. Here, we uncover Arabidopsis Methyl-CpG-Binding Domain 7 (MBD7) and Increased DNA Methylation 3 (IDM3)  as anti-silencing factors that prevent transgene repression and genome-wide DNA hypermethylation.  MBD7 preferentially binds to highly methylated, CG-dense regions associated with non-CG methylation  and physically associates with other anti-silencing factors, including the histone acetyltransferase  IDM1, IDM2, and IDM3. IDM1 and IDM2 were previously shown to facilitate active DNA demethylation  by the 5-methylcytosine DNA glycosylase/lyase ROS1. Thus, MBD7 tethers the IDM proteins to methylated DNA,  which enables the function of DNA demethylases that in turn establish chromatin boundaries and limit DNA methylation. Overall design: Whole genome methylation maps of idm3-3, mbd7-2(CS876032) and Col-0 WT were generated using BS-seq