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:• Evolutionarily conserved SWI-SNF ATP-dependent chromatin remodeling complexes (CRCs) change nucleosome positioning and chromatin states, affecting gene expression to regulate important regulatory processes controlling such as proper development and hormonal signalling pathways. • In our study we used transcript profiling, chromatin immunoprecipitation (ChIP), exhaustive protein-protein interaction study including mass-spectrometry, yeast-two-hybrid and bimolecular fluorescence complementation (BiFC) along with hormone and metabolite profiling, and phenotype assessments to distinguish the functions of Arabidopsis SWP73A and SWP73B subunits in Arabidopsis. • We identified a novel subclass of SWI/SNF chromatin remodelling complexes defined by the presence of SWP73A subunit. Therefore, we propose a refined classification of SWI/SNF CRCs in Arabidopsis, introducing BAS-A (SWP73A-containing) and BAS-B (SWP73B-containing) subclasses. The SWP73A and SWP73B-carrying subclasses of SWI/SNF CRCs exhibit differential properties demonstrated by distinct chromatin binding patterns and divergent effect on hormone biosynthesis and metabolism. We found that SWP73A plays a specific role that cannot be fully compensated by SWP73B. We recognized that some atypical subclasses of SWI/SNF CRCs may be likely formed in mutant lines with inactivated SWP73 subunits. • Our study reveals that the duplication of the SWP73 subunit contributes to unique and shared functions of subclasses of SWI/SNF CRCs in the control of various regulatory processes in Arabidopsis.
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.