Mutation of SMARCA4 (BRG1), the ATPase of BAF (mSWI/SNF) and PBAF complexes, contributes to a range of malignancies and neurologic disorders. Unfortunately, the effects of SMARCA4 missense mutations have remained uncertain. Here we show that SMARCA4 cancer missense mutations target conserved ATPase surfaces and disrupt the mechanochemical cycle of remodeling. We find that heterozygous expression of mutants alters the open chromatin landscape at thousands of sites across the genome. Loss of DNA accessibility does not directly overlap with Polycomb accumulation, but is enriched in 'A compartments' at active enhancers, which lose H3K27ac but not H3K4me1. Affected positions include hundreds of sites identified as superenhancers in many tissues. Dominant-negative mutation induces pro-oncogenic expression changes, including increased expression of Myc and its target genes. Together, our data suggest that disruption of enhancer accessibility represents a key source of altered function in disorders with SMARCA4 mutations in a wide variety of tissues.

• MeSH
• adenosintrifosfatasy metabolismus   MeSH
• chromatin chemie   MeSH
• DNA-helikasy genetika   MeSH
• dominantní geny * MeSH
• epigenomika MeSH
• genotyp MeSH
• heterozygot MeSH
• jaderné proteiny genetika   MeSH
• kultivační média MeSH
• lidé MeSH
• missense mutace MeSH
• multivariační analýza MeSH
• mutace * MeSH
• myší embryonální kmenové buňky cytologie   MeSH
• myši transgenní MeSH
• myši MeSH
• nádory genetika   MeSH
• polycomb proteiny genetika   MeSH
• restrukturace chromatinu MeSH
• sekvenční analýza RNA MeSH
• transkripční faktory genetika   MeSH
• zesilovače transkripce MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• adenosintrifosfatasy MeSH
• chromatin MeSH
• DNA-helikasy MeSH
• jaderné proteiny MeSH
• kultivační média MeSH
• polycomb proteiny MeSH
• SMARCA4 protein, human MeSH Prohlížeč
• transkripční faktory MeSH

The information on candidate cancer driver alterations available from public databases is often descriptive and of limited mechanistic insight, which poses difficulties for reliable distinction between true driver and passenger events. To address this challenge, we performed in-depth analysis of whole-exome sequencing data from cell lines generated by a barrier bypass-clonal expansion (BBCE) protocol. The employed strategy is based on carcinogen-driven immortalization of primary mouse embryonic fibroblasts and recapitulates early steps of cell transformation. Among the mutated genes were almost 200 COSMIC Cancer Gene Census genes, many of which were recurrently affected in the set of 25 immortalized cell lines. The alterations affected pathways regulating DNA damage response and repair, transcription and chromatin structure, cell cycle and cell death, as well as developmental pathways. The functional impact of the mutations was strongly supported by the manifestation of several known cancer hotspot mutations among the identified alterations. We identified a new set of genes encoding subunits of the BAF chromatin remodeling complex that exhibited Ras-mediated dependence on PRC2 histone methyltransferase activity, a finding that is similar to what has been observed for other BAF subunits in cancer cells. Among the affected BAF complex subunits, we determined Smarcd2 and Smarcc1 as putative driver candidates not yet fully identified by large-scale cancer genome sequencing projects. In addition, Ep400 displayed characteristics of a driver gene in that it showed a mutually exclusive mutation pattern when compared with mutations in the Trrap subunit of the TIP60 complex, both in the cell line panel and in a human tumor data set. We propose that the information generated by deep sequencing of the BBCE cell lines coupled with phenotypic analysis of the mutant cells can yield mechanistic insights into driver events relevant to human cancer development.

• MeSH
• exom genetika   MeSH
• fibroblasty MeSH
• lidé MeSH
• mutace MeSH
• myši MeSH
• nádorová transformace buněk genetika   MeSH
• nádorové proteiny genetika   MeSH
• nádory genetika   MeSH
• primární buněčná kultura MeSH
• vysoce účinné nukleotidové sekvenování * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• nádorové proteiny MeSH