LFQMS of RING2 (RING1B, RNF2) immunoprecipitation from MDA-MB-231 and T47D breast cancer cells

Polycomb repressive complex PRC1 is essential for gene regulation in numerous cell fate decisions. We show that RING1B (RING2, RNF2) and canonical PRC1 (cPRC1) genes are amplified and overexpressed in breast cancer (BC). Moreover, cPRC1 complexes functionally associate with genes regulated by cell type specific key transcription factors such as estrogen receptor (ER) in ER+ tumor cells and BRD4 in triple negative BC cells. cPRC1 is recruited to active enhancers in a manner independent of PRC2 and RING1B enzymatic activity. RING1B regulates enhancer activity and gene transcription not only by promoting the expression of BC oncogenes but also by regulating chromatin accessibility for oncogenic transcription factors. RING1B recruitment, and thus PRC1 association, to active enhancers occurs in multiple cancers.