DNA glycosylases recognize and excise damaged basesfrom DNA, inducing their replacement through the base excision repair system(BER). Under particular circumstances such process alters DNA methylation. Inplants, only a few DNA glycosylases have been characterized at the functionallevel. Our group recently described the gene expression pattern and subcellularlocalization of MBD4 (methyl-binding domain protein 4), belonging to theHhH-GDP superfamily. With the aim to identify nuclear genomic targets of thisenzyme, we used CHOP-PCR (methylation-sensitive enzyme digestion followed byPCR) analysis to compare samples obtained from wild-type (WT), mdb4 mutants and MBD4 overexpressing(MBD4-OE) plants. Studies were conducted at basal and stress conditions. Severalloci altering DNA methylation sensitive to MBD4 associate to heterochromatindomains targeted by RdDM (RNA-directed DNA methylation). In addition, weevaluated subnuclear localization of MBD4 by confocal microscopy. These studiesincluded two MBD4 splicing isoforms expressed in planta. Subnuclear partitioning of these isoforms and theirputative relationship with DNA targets will be presented. We will also provideevidence that MBD4 plays an important function regulating chromatin methylationstate under stress.