Chisayo Kozuka

Keywords bivalent chromatin Polycomb Trithorax epigenetic inheritance mouse oocyte MLL2 genomic imprinting placenta Introduction Polycomb group (PcG) and Trithorax group (TrxG) proteins are evolutionarily highly conserved across the metazoan kingdom and play fundamental roles in gene regulation in development and disease.1,2,3 PcG and TrxG proteins repress and promote transcription, respectively, and often form long-lasting epigenetic memory.

Abstract Mammalian oocytes establish a unique landscape of histone modifications, some of which are inherited by early embryos. How histone variants shape the maternal histone landscape remains unknown. Here we map histone H2A variants in mouse fully grown oocytes (FGOs) and find that H2A.Z forms broad domains across intergenic regions, along non-canonical H3K4me3 (ncH3K4me3).

Abstract Parental epigenomes are established during gametogenesis. While they are largely reset after fertilization, broad domains of Polycomb repressive complex 2 (PRC2)-mediated formation of lysine 27–trimethylated histone H3 (H3K27me3) are inherited from oocytes in mice. How maternal H3K27me3 is established and inherited by embryos remains elusive. Here, we show that PRC1-mediated formation of lysine 119–monoubiquititinated histone H2A (H2AK119ub1) confers maternally heritable H3K27me3.