Similar Datasets
Project description:Exhausted CD8 T cells (TEX) arise during chronic viral infections and cancer and limit disease control. Three major sequential epigenetic remodeling events occur as naïve CD8 T cells (TN) differentiate into TEX: initial activation, early bifurcation between effector (TEFF) and TEX precursors, and later differentiation of effector-like and terminal TEX subsets from progenitor TEX. The epigenetic factors mediating these transitions remain poorly understood. Here, we uncovered distinct roles for two versions of the SWI/SNF chromatin remodeling complex, BAF and PBAF, in TEX differentiation using in vivo CRISPR screening. Disruption of BAF ablated antigen-specific CD8 T cells early in chronic infection, suggesting a requirement for BAF-mediated remodeling in the early epigenetic remodeling events. In contrast, depletion of PBAF subunits enhanced TEX formation and promoted progenitor TEX differentiation into more differentiated TEX subsets by limiting accessibility of TCF-1 binding sites. Loss of PBAF improved tumor control alone and in combination with anti-PD-L1. Simultaneous depletion of BAF- and PBAF-specific subunits revealed that BAF is required for the beneficial impact of loss of PBAF on TEX differentiation. Thus, BAF and PBAF regulate epigenetic transitions in CD8 T cell differentiation, with PBAF acting at a later stage in exhaustion as a guardian to limit full TEX differentiation and preserve TEX progenitor populations with implications for cancer immunotherapy.
2023-05-31 | GSE211410 | GEO
Project description:Exhausted CD8 T cells (TEX) arise during chronic viral infections and cancer and limit disease control. Three major sequential epigenetic remodeling events occur as naïve CD8 T cells (TN) differentiate into TEX: initial activation, early bifurcation between effector (TEFF) and TEX precursors, and later differentiation of effector-like and terminal TEX subsets from progenitor TEX. The epigenetic factors mediating these transitions remain poorly understood. Here, we uncovered distinct roles for two versions of the SWI/SNF chromatin remodeling complex, BAF and PBAF, in TEX differentiation using in vivo CRISPR screening. Disruption of BAF ablated antigen-specific CD8 T cells early in chronic infection, suggesting a requirement for BAF-mediated remodeling in the early epigenetic remodeling events. In contrast, depletion of PBAF subunits enhanced TEX formation and promoted progenitor TEX differentiation into more differentiated TEX subsets by limiting accessibility of TCF-1 binding sites. Loss of PBAF improved tumor control alone and in combination with anti-PD-L1. Simultaneous depletion of BAF- and PBAF-specific subunits revealed that BAF is required for the beneficial impact of loss of PBAF on TEX differentiation. Thus, BAF and PBAF regulate epigenetic transitions in CD8 T cell differentiation, with PBAF acting at a later stage in exhaustion as a guardian to limit full TEX differentiation and preserve TEX progenitor populations with implications for cancer immunotherapy.
2023-05-31 | GSE211409 | GEO
Project description:Distinct SWI/SNF chromatin remodelling complexes act differentially to maintain stem-like exhausted CD8 T cells.
| PRJNA870141 | ENA
Project description:Distinct SWI/SNF chromatin remodelling complexes act differentially to maintain stem-like exhausted CD8 T cells [ATAC-seq]
| PRJNA870147 | ENA
Project description:Distinct SWI/SNF chromatin remodelling complexes act differentially to maintain stem-like exhausted CD8 T cells [RNA-seq]
| PRJNA870148 | ENA
Project description:Multi-subunit ATPase-dependent chromatin remodelling complexes SWI/SNF (switch/sucrose non-fermentable) are fundamental epigenetic regulators of gene transcription. Functional genomic studies revealed a remarkable mutation prevalence of SWI/SNF-encoding genes in 20-25% of all human cancers, frequently driving oncogenic programmes. Some SWI/SNF-mutant cancers are hypersensitive to perturbations in other SWI/SNF subunits, regulatory proteins and distinct biological pathways, often resulting in sustained anticancer effects and synthetic lethal interactions. Exploiting these vulnerabilities is a promising therapeutic strategy. Here, we review the importance of SWI/SNF chromatin remodellers in gene regulation as well as mechanisms leading to assembly defects and their role in cancer development. We will focus in particular on emerging strategies for the targeted therapy of SWI/SNF-deficient cancers using chemical probes, including proteolysis targeting chimeras, to induce synthetic lethality.
| S-EPMC8154588 | biostudies-literature
Project description:SWI/SNF complexes are ATP-dependent chromatin remodelling enzymes that have been implicated in the regulation of gene expression in yeast and higher eukaryotes. BRG1, a catalytic subunit in the mammalian SWI/SNF complex, is required for transcriptional activation by the estrogen receptor, but the mechanisms by which the complex is recruited to estrogen target genes are unknown. Here, we have identified an interaction between the estrogen receptor and BAF57, a subunit present only in mammalian SWI/SNF complexes, which is stimulated by estrogen and requires both a functional hormone-binding domain and the DNA-binding region of the receptor. We also found an additional interaction between the p160 family of coactivators and BAF57 and demonstrate that the ability of p160 coactivators to potentiate transcription by the estrogen receptor is dependent on BAF57 in transfected cells. Moreover, chromatin immunoprecipitation assays demonstrated that BAF57 is recruited to the estrogen-responsive promoter, pS2, in a ligand-dependent manner. These results suggest that one of the mechanisms for recruiting SWI/SNF complexes to estrogen target genes is by means of BAF57.
| S-EPMC126156 | biostudies-literature
Project description:Multiple positions within the SWI/SNF chromatin remodeling complex can be filled by mutually exclusive subunits. Inclusion or exclusion of these proteins defines many unique forms of SWI/SNF and has profound functional consequences. Often this complex is studied as a single entity within a particular cell type and we understand little about the functional relationship between these biochemically distinct forms of the remodeling complex. Here we examine the functional relationships among three complex-specific ARID (AT-Rich Interacting Domain) subunits using genome-wide chromatin immunoprecipitation, transcriptome analysis, and transcription factor binding maps. We find widespread overlap in transcriptional regulation and the genomic binding of distinct SWI/SNF complexes. ARID1B and ARID2 participate in wide-spread cooperation to repress hundreds of genes. Additionally, we find numerous examples of competition between ARID1A and another ARID, and validate that gene expression changes following loss of one ARID are dependent on the function of an alternative ARID. These distinct regulatory modalities are correlated with differential occupancy by transcription factors. Together, these data suggest that distinct SWI/SNF complexes dictate gene-specific transcription through functional interactions between the different forms of the SWI/SNF complex and associated co-factors. Most genes regulated by SWI/SNF are controlled by multiple biochemically distinct forms of the complex, and the overall expression of a gene is the product of the interaction between these different SWI/SNF complexes. The three mutually exclusive ARID family members are among the most frequently mutated chromatin regulators in cancer, and understanding the functional interactions and their role in transcriptional regulation provides an important foundation to understand their role in cancer.
| S-EPMC4699898 | biostudies-literature
Project description:The SWI/SNF family of ATP-dependent chromatin-remodeling factors plays a central role in eukaryotic transcriptional regulation. In yeast and human cells, two subclasses have been recognized: one comprises yeast SWI/SNF and human BAF, and the other includes yeast RSC and human PBAF. Therefore, it was puzzling that Drosophila appeared to contain only a single SWI/SNF-type remodeler, the Brahma (BRM) complex. Here, we report the identification of two novel BRM complex-associated proteins: Drosophila Polybromo and BAP170, a conserved protein not described previously. Biochemical analysis established that Drosophila contains two distinct BRM complexes: (i) the BAP complex, defined by the presence of OSA and the absence of Polybromo and BAP170, and (ii) the PBAP complex, containing Polybromo and BAP170 but lacking OSA. Determination of the genome-wide distributions of OSA and Polybromo on larval salivary gland polytene chromosomes revealed that BAP and PBAP display overlapping but distinct distribution patterns. Both complexes associate predominantly with regions of open, hyperacetylated chromatin but are largely excluded from Polycomb-bound repressive chromatin. We conclude that, like yeast and human cells, Drosophila cells express two distinct subclasses of the SWI/SNF family. Our results support a close reciprocity of chromatin regulation by ATP-dependent remodelers and histone-modifying enzymes.
| S-EPMC381637 | biostudies-literature
Project description:BackgroundSWI/SNF chromatin remodeling genes are required for normal acute responses to alcohol in C. elegans and are associated with alcohol use disorder in two human populations. In an effort to discover the downstream genes that are mediating this effect, we identified SWI/SNF-regulated genes in C. elegans.ResultsTo identify SWI/SNF-regulated genes in adults, we compared mRNA expression in wild type and swsn-1(os22ts) worms under conditions that produce inactive swsn-1 in mature cells. To identify SWI/SNF-regulated genes in neurons, we compared gene expression in swsn-9(ok1354) null mutant worms that harbor a neuronal rescue or a control construct. RNA sequencing was performed to an average depth of 25 million reads per sample using 50-base, paired-end reads. We found that 6813 transcripts were significantly differentially expressed between swsn-1(os22ts) mutants and wild-type worms and 2412 transcripts were significantly differentially expressed between swsn-9(ok1354) mutants and swsn-9(ok1354) mutants with neuronal rescue. We examined the intersection between these two datasets and identified 603 genes that were differentially expressed in the same direction in both comparisons; we defined these as SWI/SNF-regulated genes in neurons and in adults. Among the differentially expressed genes was cbp-1, a C. elegans homolog of the mammalian CBP/p300 family of histone acetyltransferases. CBP has been implicated in the epigenetic regulation in response to alcohol in animal models and a polymorphism in the human CBP gene, CREBBP, has been associated with alcohol-related phenotypes. We found that cbp-1 is required for the development of acute functional tolerance to alcohol in C. elegans.ConclusionsWe identified 603 transcripts that were regulated by two different SWI/SNF complex subunits in adults and in neurons. The SWI/SNF-regulated genes were highly enriched for genes involved in membrane rafts, suggesting an important role for this membrane microdomain in the acute alcohol response. Among the differentially expressed genes was cbp-1; CBP-1 homologs have been implicated in alcohol responses across phyla and we found that C. elegans cbp-1 was required for the acute alcohol response in worms.
| S-EPMC7507291 | biostudies-literature