H3K27me3 and the PRC1-H2AK119ub pathway cooperatively maintain heterochromatin and transcriptional silencing after the loss of H3K9 methylation

Our findings highlight a compensatory role for uH2A in preserving heterochromatin structure after the loss of other repressive chromatin modifications. The PRC1-uH2A pathway plays a critical role in maintaining the integrity of B compartments and suggests that heterochromatin architecture is supported by a network of redundant epigenetic mechanisms in mammalian cells.