The DREAM complexes prevent genomic hypermethylation by repressing the expression of genes required for maintenance of DNA methylation [ChIP-seq]

We identified TCX5, an Arabidopsis tesmin/TSO1-like CXC domain-containing transcription factor, and demonstrated that TCX5 functions redundantly with its paralog, TCX6, to prevent genomic hypermethylation and transcriptional silencing. TCX5 binds to the promoters of genes required for cell proliferation and maintenance of DNA methylation to repress the expression of these genes. Consistently, the tcx5/tcx6 double mutant showed enhanced cell proliferation, enlarged organ size, and increased genome-wide methylation. This study reveals how maintenance of DNA methylation is coordinated with cell division to prevent genomic hypermethylation. Given that the DREAM complexes are conserved from plants to animals, the prevention of DNA hypermethylation by the DREAM complexes may represent a conserved mechanism in higher eukaryotes. Anti-FLAG M2 Magnetic Beads (M8823; Sigma-Aldrich) were used for the IP of TCX5–3xFlag.