Brg1 defect causes aberrent nucleosome landscape and affects totipotency & pluripotency transcriptional factors binding during embryogenesis
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ABSTRACT:
PROVIDER: PRJNA1256306 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| Other | ||||
| SRR33333330_1.fastq.gz | Fastqsanger.gz | |||
| SRR33333330_2.fastq.gz | Fastqsanger.gz | |||
| SRR33333331_1.fastq.gz | Fastqsanger.gz | |||
| SRR33333331_2.fastq.gz | Fastqsanger.gz |
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Project description:Mammalian embryogenesis involves intricate epigenetic reprogramming and chromatin remodeling. In this study, we investigated the role of Brg1, a catalytic ATPase subunit of the SWI/SNF complex, in early embryonic development and mouse embryonic stem cell (mESC) pluripotency. By generating Smarca4 flox/flox Gdf9-Cre female mice to knockout Brg1 in MII oocytes and using CRISPR-Cas9 to knockout Brg1 in mESCs, we found that Brg1 deficiency led to multiple defects. In mouse embryos, maternal knockout of Brg1 caused reduced blastocyst formation, delayed development, elevated nucleosome occupancy at gene promoters, and dysregulation of zygotic genome activation (ZGA) genes, potentially due to disrupted binding of totipotency-related transcription factors (TFs). In mESCs, Brg1 knockout resulted in abnormal clone morphology, decreased pluripotency marker expression, and reduced cell proliferation. Brg1 affected pluripotency mainly by influencing the binding of pluripotency-related TFs such as Oct4 through enhancer accessibility. We identified those TFs as totipotency/pluripotency Brg1-dependent TFs. Overall, this study demonstrates the crucial role of Brg1 in ZGA and mESC identity maintenance in affecting specific TF binding on proximal and distal regulatory elements.
2025-05-09 | GSE295748 | GEO
Project description:Mammalian embryogenesis involves intricate epigenetic reprogramming and chromatin remodeling. In this study, we investigated the role of Brg1, a catalytic ATPase subunit of the SWI/SNF complex, in early embryonic development and mouse embryonic stem cell (mESC) pluripotency. By generating Smarca4 flox/flox Gdf9-Cre female mice to knockout Brg1 in MII oocytes and using CRISPR-Cas9 to knockout Brg1 in mESCs, we found that Brg1 deficiency led to multiple defects. In mouse embryos, maternal knockout of Brg1 caused reduced blastocyst formation, delayed development, elevated nucleosome occupancy at gene promoters, and dysregulation of zygotic genome activation (ZGA) genes, potentially due to disrupted binding of totipotency-related transcription factors (TFs). In mESCs, Brg1 knockout resulted in abnormal clone morphology, decreased pluripotency marker expression, and reduced cell proliferation. Brg1 affected pluripotency mainly by influencing the binding of pluripotency-related TFs such as Oct4 through enhancer accessibility. We identified those TFs as totipotency/pluripotency Brg1-dependent TFs. Overall, this study demonstrates the crucial role of Brg1 in ZGA and mESC identity maintenance in affecting specific TF binding on proximal and distal regulatory elements.
2025-05-23 | GSE297843 | GEO
Project description:Brg1 defect causes aberrent nucleosome landscape and affects totipotency & pluripotency transcriptional factors binding during embryogenesis [MNase-Seq]
| PRJNA1266270 | ENA
Project description:The SWI/SNF complex remodels chromatin in an ATP-dependent manner through the ATPase subunits BRG1 and BRM. Chromatin remodeling alters nucleosome structure to change gene expression, however aberrant remodeling and gene expression can result in cancer. The function and localization on chromatin of the SWI/SNF complex depends on the protein makeup of the complex. Here we report the protein-protein interactions of wild-type BRG1 or mutant BRG1 in which the HSA domain has been deleted (BRG1-HSA). We demonstrate the interaction of BRG1 with most SWI/SNF complex members and a failure of a number of these members to interact with BRG1-HSA. These results demonstrate that the HSA domain of BRG1 is a critical interaction platform for the correct formation of SWI/SNF remodeling complexes.
2023-02-15 | PXD029647 | Pride
Project description:Enhancers of transcription activate transcription via binding of sequence-specific transcription factors to their target sites in chromatin. In this report, we identify GATA1-bound enhancers genome-wide and find a global reorganization of the nucleosomes at these enhancers during differentiation of hematopoietic stem cells (HSCs) to erythrocytes. We show that the catalytic subunit BRG1 of BAF complexes localizes to these enhancers during differentiation and generates a longer nucleosome repeat length surrounding the GATA1 sites by shifting the flanking nucleosomes away. Intriguing, we find that the nucleosome shifting specifically facilitates binding of TAL1 but not GATA1, which subsequently activates transcription of target genes. Human hematopoietic stem cells (referred as CD34+ cells) were differentiated into erythroid lineage expressing the cell surface marker CD36 (referred as CD36+ cells). To study the function of ATP-dependent chromatin remodeling BAF complexes in the establishment of erythroid specific enhancers during differentiation, we mapped the genome-wide binding sites of GATA1 and TAL1, the key transcription regulators of erythroid differentiation, in CD36+ cells, then determined the genomic positions of the catalytic subunit BRG1 of the BAF complexes and the nucleosome landscapes, by ChIP-Seq and Mnase-Seq, respectively, for both HSCs and the differentiated cells. We compared changes in nucleosome landscapes with BRG1 binding at GATA1 and TAL1 binding sites and found that BRG1 binding is correlated with nucleosome shifting away from the binding sites, which is critical for TAL1 binding. To confirm that BRG1 is responsible for the nucleosome shift, we knocked down BRG1 in CD36+ cells and analyzed the nucleosome changes in the knockdown cells. The data indicated that inhibition of BRG1 caused a nucleosome shift towards the GATA1 or TAL1 sites, indicating that BRG1 is indeed responsible for the observed nucleosome shift.
2011-07-01 | E-GEOD-26501 | biostudies-arrayexpress
Project description:Mammalian SWI/SNF-related complexes have been implicated in cancer based on some of the subunits physically interacting with RB and other proteins involved in carcinogenesis. Additionally, several subunits are mutated or not expressed in tumor-derived cell lines. Strong evidence for a role in tumorigenesis in vivo, however, has been limited to SNF5 mutations that result primarily in malignant rhabdoid tumors (MRTs) in humans and MRTs as well as other sarcomas in mice. We previously generated a null mutation of the Brg1 catalytic subunit in the mouse and reported that homozygotes die during embryogenesis. Here, we demonstrate that Brg1 heterozygotes are susceptible to mammary tumors that are fundamentally different than Snf5 tumors. First, mammary tumors are carcinomas not sarcomas. Second, Brg1+/- tumors arise because of haploinsufficiency rather than loss of heterozygosity (LOH). Third, Brg1+/- tumors exhibit genomic instability but not polyploidy based on array CGH results. We monitored Brg1+/-, Brm-/- double-mutant mice but did not observe any tumors resembling those from Snf5 mutants, indicating that the Brg1+/- and Snf5+/- tumor phenotypes do not differ simply because Brg1 has a closely related paralog whereas Snf5 does not. These findings demonstrate that BRG1 and SNF5 are not functionally equivalent but protect against cancer in different ways. We also demonstrate that Brg1+/- mammary tumors have relatively heterogeneous gene expression profiles with similarities and differences compared to other mouse models of breast cancer. The Brg1+/- expression profiles are not particularly similar to mammary tumors from Wap-T121 transgenic line where RB is perturbed. We were also unable to detect a genetic interaction between the Brg1+/- and Rb+/- tumor phenotypes. These latter findings do not support a BRG1-RB interaction in vivo. Experiment Overall Design: 14 microarrays consisting of 12 unique Brg1+/- murine mammary Experiment Overall Design: tumors
2008-06-18 | E-GEOD-8516 | biostudies-arrayexpress
Project description:Acquisition of new stem cell fates relies on the dissolution of the prior regulatory network sustaining the existing cell fates. Currently, extensive insights have been revealed for the totipotency regulatory network around the zygotic genome activation (ZGA) period. However, how the dissolution of the totipotency network is triggered to ensure the timely embryonic development following ZGA is largely unknown. In this study, we identified the unexpected role of a highly expressed 2C embryo specific transcription factor, ZFP352, in facilitating the dissolution of the totipotency network. We found that ZFP352 has bifurcated binding and regulation towards two different retrotransposon sub-families. ZFP352 coordinates with DUX to bind and regulate the 2C specific MT2_Mm sub-family. On the other hand, without DUX, ZFP352 switched affinity to bind extensively onto SINE_B1/Alu sub-family. This leads to the activation of later developmental programs like ubiquitination pathways, to facilitate the dissolution of the 2C state. Correspondingly, depleting ZFP352 in mouse embryos impaired the 2C to morula transition process. Thus, through differential regulation of MT2_Mm and SINE_B1/Alu, ZFP352 can trigger spontaneous dissolution of the totipotency network. Our study highlights the importance of different retrotransposons sub-families in facilitating the timely and programmed cell fates transition during early embryogenesis.
2023-06-01 | GSE222636 | GEO
Project description:Mammalian SWI/SNF-related complexes have been implicated in cancer based on some of the subunits physically interacting with RB and other proteins involved in carcinogenesis. Additionally, several subunits are mutated or not expressed in tumor-derived cell lines. Strong evidence for a role in tumorigenesis in vivo, however, has been limited to SNF5 mutations that result primarily in malignant rhabdoid tumors (MRTs) in humans and MRTs as well as other sarcomas in mice. We previously generated a null mutation of the Brg1 catalytic subunit in the mouse and reported that homozygotes die during embryogenesis. Here, we demonstrate that Brg1 heterozygotes are susceptible to mammary tumors that are fundamentally different than Snf5 tumors. First, mammary tumors are carcinomas not sarcomas. Second, Brg1+/- tumors arise because of haploinsufficiency rather than loss of heterozygosity (LOH). Third, Brg1+/- tumors exhibit genomic instability but not polyploidy based on array CGH results. We monitored Brg1+/-, Brm-/- double-mutant mice but did not observe any tumors resembling those from Snf5 mutants, indicating that the Brg1+/- and Snf5+/- tumor phenotypes do not differ simply because Brg1 has a closely related paralog whereas Snf5 does not. These findings demonstrate that BRG1 and SNF5 are not functionally equivalent but protect against cancer in different ways. We also demonstrate that Brg1+/- mammary tumors have relatively heterogeneous gene expression profiles with similarities and differences compared to other mouse models of breast cancer. The Brg1+/- expression profiles are not particularly similar to mammary tumors from Wap-T121 transgenic line where RB is perturbed. We were also unable to detect a genetic interaction between the Brg1+/- and Rb+/- tumor phenotypes. These latter findings do not support a BRG1-RB interaction in vivo. Keywords: reference X sample
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Project description:Totipotency is the ability of a single cell to give rise to all the differentiated cells that build the conceptus, yet how to capture this property in vitro remains incompletely understood. Defining totipotency relies upon a variety of assays of variable stringency. Here we describe criteria to define totipotency. We illustrate how distinct criteria of increasing stringency can be used to judge totipotency by evaluating candidate totipotent cell types in the mouse, including early blastomeres and expanded or extended pluripotent stem cells. Our data challenge the notion that expanded or extended pluripotent states harbor increased totipotent potential relative to conventional embryonic stem cells under in vivo conditions.
2020-10-13 | GSE145609 | GEO
Project description:The haploid multicellular male gametophyte of plants, the pollen grain, is a terminally differentiated structure whose function ends at fertilization. Unlike pollen grains, the immature gametophyte retains its capacity for totipotent growth when cultured in vitro. Haploid embryo production from cultured immature male gametophytes is a widely used plant breeding and propagation technique that was described nearly 50 years ago, but one that is poorly understood at the mechanistic level. Using a chemical approach, we show that the switch to haploid embryogenesis is controlled by the activity of histone deacetylases (HDACs). Blocking HDAC activity with trichostatin A (TSA) in cultured immature male gametophytes of Brassica napus leads to a large increase in the proportion of cells that switch from pollen to embryogenic growth. Embryogenic growth is enhanced by, but not dependent on, the high temperature stress that is normally used to induce haploid embryogenesis in B. napus. The immature male gametophyte of Arabidopsis thaliana, which is recalcitrant for haploid embryo development in culture, also forms embryogenic cell clusters after TSA treatment. TSA treatment of immature male gametophytes for as little as eight hours was accompanied by hyperacetylation of histones H3 and H4, and by the upregulation of genes involved in cell-cycle progression, the auxin pathway and cell wall catabolism pathways. We propose that the totipotency of the immature male gametophyte in planta is kept in check by an HDAC-dependent mechanism, and that high temperature or other stresses used to induce haploid embryo development in culture impinge on this HDAC-dependent pathway. 8 samples were analyzed. We generated the following pairwise comparisons between treatment and the corresponding mock treatment: TSA+CHX (2 replicates) vs CHX (2 replicates); TSA (2 replicates) vs DMSO (2 replicates).
2016-07-03 | E-GEOD-49070 | biostudies-arrayexpress