Inhibits PRC2/EED-EZH1 and PRC2/EED-EZH2 complex function by inhibiting EZH1/EZH2 methyltransferase activity, thereby causing down-regulation of histone H3 trimethylation on 'Lys-27' (H3K27me3) (PubMed:29909548, PubMed:31086175, PubMed:31451685, PubMed:30923826). Probably inhibits methyltransferase activity by limiting the stimulatory effect of cofactors such as AEBP2 and JARID2 (PubMed:30923826). Inhibits H3K27me3 deposition during spermatogenesis and oogenesis (By similarity). Interacts with PRC2/EED-EZH1 complex member EZH1 and with PRC2/EED-EZH2 complex member EZH2; the interaction blocks EZH1/EZH2 methyltransferase activity (PubMed:29909548, PubMed:31086175, PubMed:31451685, PubMed:30923826). Interacts (via C-terminus) with SUZ12 which is a member of the PRC2/EED-EZH1 and PRC2/EED-EZH2 complexes (PubMed:29909548, PubMed:30923826). In testis, detected in male germ cells inside the seminiferous tubules, especially in spermatogonia and round spermatids (at protein level) (PubMed:31451685). In the ovary, expressed in primordial follicles and oocytes but not the external follicle cells (at protein level) (PubMed:31451685).