Polycomb group (PcG) protein. Catalytic subunit of some PcG multiprotein complex, which methylates 'Lys-27' of histone H3, leading to transcriptional repression of the affected target genes, mainly abscisic acid (ABA) responsive elements (PubMed:17881378, PubMed:30307069). Required to regulate floral development by repressing the AGAMOUS homeotic gene in leaves, inflorescence stems and flowers (PubMed:17881378). Together with ATX1, modulates AG nucleosome methylation statement (PubMed:17881378). Regulates the antero-posterior organization of the endosperm, as well as the division and elongation rates of leaf cells. PcG proteins act by forming multiprotein complexes, which are required to maintain the transcriptionally repressive state of homeotic genes throughout development. PcG proteins are not required to initiate repression, but to maintain it during later stages of development. L-lysyl-[histone] + S-adenosyl-L-methionine = H(+) + N(6)-methyl-L-lysyl-[histone] + S-adenosyl-L-homocysteine Probable component of a PcG complex. In plants, PcG complexes are probably composed of a member of the EZ family (CLF or MEA), FIE, and a member of the VEFS family (FIS2, VRN2 or EMF2) (By similarity). Interacts with FIE (PubMed:14871310). Interacts with RING1A (PubMed:19097900). Binds to ALP1 (PubMed:26642436). Interacts with BLI (PubMed:20647345). Binds to ATX1 in the nucleus (PubMed:17881378). Interacts with EOL1 (PubMed:28428341). Strongly expressed throughout the apical meristem, leaf primordia, and leaves of 7-8 day-old seedling. Weakly expressed in the vasculature of hypocotyl. Strongly expressed throughout the young stages 1 and 2 floral meristems that arose on the flanks of the apex. In stage 3 and 4 flowers, it is expressed in the emerging sepal primordia and in the dome of the floral meristem. During stages 6 and 7, it is strongly expressed in developing petal and stamen, and weakly expressed in the sepals. Late in floral development, at stage 12, it is weakly expressed in all floral whorls, and expressed at intermediate level in petals and ovules. Expressed in all four whorls throughout flower development. Misexpression of AGAMOUS, recognizable phenotypes (e.g. curly leaves, and early flowering time) and loss of H3K27me3 histone H3-tail marks (PubMed:17881378). Double mutant plants atx1 clf exhibits normal leaf-phenotype and flowering time (PubMed:17881378). The double mutant clf-50 swn-1 is hypersensitive to abscisic acid (ABA) associated with reduced ABA-responsive genes repression by histone H3 'Lys-27' methylation (H3K27me3) (PubMed:30307069). Belongs to the class V-like SAM-binding methyltransferase superfamily. Histone-lysine methyltransferase family. EZ subfamily.