Polycomb group (PcG) protein. 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. They act via the methylation of histones, rendering chromatin heritably changed in its expressibility (PubMed:23505380, PubMed:24020752). Involved in the regulation of seed endosperm development, grain filling and seed dormancy. FIE2-containing PcG complex in seed endosperm regulates the expression of various transcription factors by trimethylation on histone H3 'Lys-27' (H3K27me3) of target genes. Involved in the overall expression regulation of a large number of nutrient metabolism genes (PubMed:23505380). Involved in the regulation of seed endosperm development. Involved in the regulation of vegetative development, particulary in stem cell maintenance in the root system, where it maintains the suppression of key differentiation regulators (PubMed:24020752). Interacts with EZ1 (Ref.1, PubMed:23150632, PubMed:23505380). Component of the polycomb repressive complex 2 (PRC2), composed of the core PRC2 components EMF2B, EZ1 and CLF. PRC2 methylates 'Lys-27' residues of histone H3 (H3K27me3), leading to transcriptional repression of the affected target gene (PubMed:23505380). Widely expressed. Plants silencing FIE2 have small and partially filled seeds, and exhibit seed germination before seed maturation (PubMed:23505380). Plant silencing FIE2 exhibit aberrant pleiotropic phenotypes in vegetative and reproductive organ generation, and derepression of some developmental regulators, such as MADS3 and OSH5 genes (PubMed:24020752). Belongs to the WD repeat ESC family.