Abstract

DNA methylation generally functions as a repressive transcriptional signal but is also known to activate gene expression. In either case, the downstream factors remain largely unknown. Here, using comparative interactomics, we isolated proteins in Arabidopsis thaliana that associate with methylated DNA . Two SU(VAR)3-9 homologues, the transcriptional anti-silencing factor SUVH1 , and SUVH3 , were among the methyl-reader candidates. SUVH1 and SUVH3 bound methylated DNA in vitro, were associated with euchromatic methylation in vivo, and formed acomplex with two DNAJ domain containing homologues, DNAJ1 and DNAJ2 . Ectopic recruitment of DNAJ1 enhanced gene transcription in plants, yeast and mammals. Thus, the SUVH proteins bind to methylated DNA and recruit the DNAJ proteins to enhance proximal gene expression, thereby counteracting the repressive effects of transposon insertion near genes.