Variant PCGF1-PRC1 links PRC2 recruitment with induced transcriptional inactivation at target genes [ChIP-seq]

Polycomb repressive complexes-1 and -2 (PRC1 and 2), silence developmental genes in spatiotemporally regulated manner during metazoan embryogenesis. How PcG proteins contribute to down-regulation of target genes upon differentiation, however, remains elusive. Here, by differentiating embryonic stem cells into embryoid bodies, we reveal a crucial role of a PCGF1 (Polycomb group RING finger protein 1)-containing variant PRC1 complex (PCGF1-PRC1) to facilitate induced down-regulation of a group of genes. Binding of PCGF1-PRC1 results in down-regulation of transcriptional activity, followed by Histone H2AK119 mono-ubiquitination (H2AK119ub1) and subsequent recruitment of PRC2, to initiate PcG-repressive domain formation. Based on these findings, we propose that PCGF1-PRC1 mediates establishment of PcG-repressive domains at target genes during differentiation. ChIP-seq analysis of mouse ES cell and embryoid body (EB)