Binds specifically to H3K4me3 regions of target genes (e.g. WUS and WOX5) promoters to repress their transcription via chromatin remodeling. Required for the shoot apical meristem (SAM) organization and maintenance, by confining WUS expression to the organizing center, and for the quiescent center (QC) development in the root apical meristem (RAM), by repressing WOX5 expression in the root proximal meristem (PubMed:18591352, PubMed:25631790). Plays a role in DNA repair and in cell-cycle control. Required for the repair of DNA double-strand breaks (DSBs), both natural and induced by genotoxic stress, by homologous recombination (HR) (PubMed:16957774). Component of a DNA-protein complex on WUS and WOX5 promoters (PubMed:25631790, PubMed:18591352). Interacts with SYD (PubMed:18591352). Forms heterodimer with BRCA1 (PubMed:16957774). Additional isoforms seem to exist. Expressed in the shoot apical meristem (SAM), roots, flowers, embryos and seedlings (PubMed:18591352). Mostly expressed in flowers and siliques, and, to a lower extent, in roots, rosette leaves, inflorescence and young cauline leaves (PubMed:16957774). Expressed specifically in the apical domains of the shoot apical meristem (SAM), inflorescences, ovules, anthers and embryos. In young seedlings, localized mainly in the outermost three to four cell layers of the main shoot apex and in developing leaf primordia and young leaves. Also present in the meristem zone of primary roots and in the initiation site of lateral roots. Up-regulated by the transcription factor ERF114. Enhanced sensitivity to genotoxic stresses (e.g. bleomycin and mitomycin C (MMC)) due to reduced intrachromosomal homologous recombination (HR) (PubMed:16957774). Meristem defects associated with ectopic WUSCHEL expression at high levels (e.g. 238 fold higher than controls) mainly in the outermost cell layers instead of the organizing center (PubMed:18591352). Abnormal quiescent center (QC) in the root apical meristem (RAM) and defects in cell differentiation leading to short roots and loss of gravitropic response, probably due to defect in columella cell differentiation. Ectopic expression of WOX5 in RAM cells that normally express ROW1 (PubMed:25631790).