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. 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 (Probable). Involved in the regulation of flowering. Promotes flowering under short day (SD) conditions. Regulates the trimethylation on histone H3 'Lys-27' (H3K27me3) of the flowering regulator LF (PubMed:25400654). L-lysyl(27)-[histone H3] + 3 S-adenosyl-L-methionine = 3 H(+) + N(6),N(6),N(6)-trimethyl-L-lysyl(27)-[histone H3] + 3 S-adenosyl-L-homocysteine Interacts with FIE1 (PubMed:23150632). Interacts with FIE2 (Ref.9, PubMed:23150632, PubMed:23505380). Component of the polycomb repressive complex 2 (PRC2), composed of the core PRC2 components FIE2, EMF2B and CLF. PRC2 methylates 'Lys-27' residues of histone H3 (H3K27me3), leading to transcriptional repression of the affected target gene. Widely expressed (PubMed:19825651). Expressed in leaves and stems. Expressed a low levels in roots, anthers, ovaries and ovules (Ref.9). Highly expressed in seed endosperm 7 days after pollination. Down-regulation of EZ1 delays flowering in short day (SD), but has no effect in long day (LD). Belongs to the class V-like SAM-binding methyltransferase superfamily. Histone-lysine methyltransferase family. EZ subfamily.