Project description:To reveal the genome-wide targets of SWI/SNF complexes in AML cells, we performed ATAC-seq in THP-1, MOLM-13, and MV-4-11 cells with or without the SWI/SNF ATPase BRM014. Analysis of the locations decreased following 24 or 72 h after addition of BRM014 revealed that SWI/SNF-dependent sites are located at enhancers occupied by PU.1, especially the blood enhancer cluster (BENC), a set of enhancers that drives expression of MYC.
Project description:SWP73 subunits of SWI/SNF chromatin remodeling complexes (CRCs) are involved in key developmental pathways in Arabidopsis. We found, using microarray that inactivation of SWP73B caused altered expression of genes belonging to various regulatory pathways, including leaf and flower development. On the basis of this experiment and our other data we concluded that SWP73B modulates major developmental pathways.
Project description:Mutations in genes encoding the various subunits of the SWI/SNF chromatin remodeling complex are frequently observed in different human cancers. In diffuse large B-cell lymphoma (DLBCL), genetic changes in BCL7A, a subunit of the SWI/SNF complex, have been recently reported but the functional role of such genetic changes remains unknown. BCL7A mutations concentrate at the first exon and the most frequently mutated hotspot is the splice donor site of the first intron. By using in vitro and in vivo analyses, we show that restoration of BCL7A drives a tumor suppressor-like phenotype. Further, we found that splice site mutations block the tumor suppressor phenotype and prevent BCL7A from binding to the SWI/SNF complex. Finally, we identified that the SWI/SNF complex accumulates mutations in a third of DLBCL tumors, especially in the GCB subtype. These discoveries highlight the tumor suppressor role of BCL7A mutations in DLBCL, and suggest that the SWI/SNF complex is involved in DLBCL pathogenesis.
Project description:Switch defective/sucrose non-fermentable (SWI/SNF) complexes are evolutionarily conserved multi-subunit machines that play vital roles in chromatin architecture regulation for modulating gene expression via sliding or ejection of nucleosomes in eukaryotes. In plants, perturbations of SWI/SNF subunits often result in severe developmental disorders. However, the subunit composition, pathways of assembly, and genomic targeting of the plant SWI/SNF complexes remain undefined. Here, we reveal that Arabidopsis SWI/SNF complexes exist in three distinct final form assemblies: BRM-associated SWI/SNF complexes (BAS), SYD-associated SWI/SNF complexes (SAS) and MINU-associated SWI/SNF complexes (MAS). We show that BAS complexes are equivalent to human ncBAF, whereas SAS and MAS complexes evolve in multiple subunits unique to plants, suggesting a plant-specific functional evolution of SWI/SNF complexes. We further demonstrate overlapping and specific genomic targeting of the three plant SWI/SNF complexes on chromatin and reveal that SAS complexes are necessary for the correct genomic localization of the BAS complexes. Finally, by focusing on the SAS and BAS complexes, we establish a requirement for both the core module subunit and the ATPase in the assembly of the plant SWI/SNF complexes. Together, our work highlights the divergence of SWI/SNF chromatin remodelers during the eukaryote evolution and provides a comprehensive landscape for understanding the plant SWI/SNF complexes organization, assembly, genomic targeting, and function.
Project description:We identify three classes of Arabidopsis SWI/SNF chromatin remodeling complexes and demonstrate that they regulate different developmental processes by affecting chromatin accessibility.
Project description:We identify three classes of Arabidopsis SWI/SNF chromatin remodeling complexes and demonstrate that they regulate different developmental processes by affecting chromatin accessibility.
Project description:We identify three classes of Arabidopsis SWI/SNF chromatin remodeling complexes and demonstrate that they regulate different developmental processes by affecting chromatin accessibility.
Project description:Advanced prostate cancer initially responds to hormonal treatment, but ultimately becomes resistant and requires more potent therapies. One mechanism of resistance seen in 10% of these patients is through lineage plasticity, which manifests in a partial or complete small cell or neuroendocrine prostate cancer (NEPC) phenotype. Here, we investigate the role of the mammalian SWI/SNF chromatin remodeling complex in NEPC. Using large patient datasets, patient-derived organoids and cancer cell lines, we identify SWI/SNF subunits that are deregulated in NEPC, demonstrate that SMARCA4 (BRG1) overexpression is associated with aggressive disease and that SMARCA4 depletion impairs prostate cancer cell growth. We also show that SWI/SNF complexes interact with different lineage-specific factors in prostate adenocarcinoma and in NEPC cells, and that induction of lineage plasticity through depletion of REST is accompanied by changes in SWI/SNF genome occupancy. These data suggest a specific role for mSWI/SNF complexes in therapy-related lineage plasticity, which may be relevant for other solid tumors.
Project description:Chromatin, in addition to its purely structural functions, is considered a major regulatory system coordinating various genetic networks in eukaryotes. Constant changes of gene expression programs are especially important for plants, which have to respond to environment by modulating their growth and development during whole lifetime. External and developmental signals can be transmitted through signaling cascades to chromatin remodeling complexes like SWI/SNF, which alter chromatin structure by moving, ejecting or restructuring nucleosomes. Genetic studies in Arabidopsis thaliana revealed that SWI/SNF chromatin remodeling complexes are critical for proper plant development and growth. Especially, BRM, a catalytic subunit of the complex, was shown to directly regulate several genes with important functions in leaf development, flowering initiation, as well as gibberellin and abscisic acid signaling. In this study, we profiled BRM global binding regions in Arabidopsis genome by ChIP-chip analysis. We found that BRM can bind to thousands of genes, many of which have key functions in hormone and stress signaling.