Genome wide identification of polycomb associated RNAs by RIP seq.
Polycomb proteins play essential roles in stem cell renewal and human disease. Recent studies of HOX genes and X inactivation have provided evidence for RNA cofactors in Polycomb repressive complex 2 (PRC2) Here we develop a RIP seq method to capture the PRC2 transcriptome and identify a genome wide pool of >9000 PRC2 interacting RNAs in embryonic stem cells. The transcriptome includes antisense, intergenic, and promoter associated transcripts, as well as many unannotated RNAs. A large number of transcripts occur within imprinted regions, oncogene and tumor suppressor loci, and stem cell related bivalent domains. We provide evidence for direct RNA protein interactions, most likely via the Ezh2 subunit. We also identify Gtl2 RNA as a PRC2 cofactor that directs PRC2 to the reciprocally imprinted Dlk1 coding gene. Thus, Polycomb proteins interact with a genome wide family of RNAs, some of which may be used as biomarkers and therapeutic targets for human disease.
Molecular cell