Is required for normal leaf, flower and seed development and controls cotyledon and leaf patterning by inhibiting premature differentiation. Regulates the expression of a subset of PcG target genes. Is required for the repression of the floral specific genes PI, SEP2, and SEP3, but also for the activation of FLC (PubMed:20647345). Involved in response to cold. Involved in the regulation of COR15A, COR15B, BAM3 and AMY3 transcripts, and ascorbate levels in response to prolonged chilling temperatures (PubMed:20674078). Interacts with CLF. May shuttle between the nucleus and the cytoplasm. Expressed in root tips, emerging lateral roots, shoot apical meristem (SAM), vasculature of cotyledons, leaves, sepals and carpels. During embryo development, expressed in the basal part and the vasculature of heart stage and torpedo stage embryos. Pleiotropic phenotype with defects in cotyledon, leaf, flower and seed development, slow growth, severe epidermal defects, including loss of cell adhesion, outgrowth of cells and increased cotyledon cell size.