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Smarcb1 Is Required For Widespread Baf Complex-Mediated Activation Of Enhancers And Bivalent Promoters., Robert T Nakayama, John L Pulice, Alfredo M Valencia, Matthew J Mcbride, Zachary M Mckenzie, Mark A Gillespie, Wai Lim Ku, Mingxiang Teng, Kairong Cui, Robert T Williams, Seth H Cassel, He Qing, Christian J Widmer, George D Demetri, Rafael A Irizarry, Keji Zhao, Jeffrey A Ranish, Cigall Kadoch

Articles, Abstracts, and Reports

Perturbations to mammalian SWI/SNF (mSWI/SNF or BAF) complexes contribute to more than 20% of human cancers, with driving roles first identified in malignant rhabdoid tumor, an aggressive pediatric cancer characterized by biallelic inactivation of the core BAF complex subunit SMARCB1 (BAF47). However, the mechanism by which this alteration contributes to tumorigenesis remains poorly understood. We find that BAF47 loss destabilizes BAF complexes on chromatin, absent significant changes in complex assembly or integrity. Rescue of BAF47 in BAF47-deficient sarcoma cell lines results in increased genome-wide BAF complex occupancy, facilitating widespread enhancer activation and opposition of Polycomb-mediated repression at bivalent promoters. We …