Multiscale reorganization of the genome following DNA damage facilitates chromosome translocations via nuclear actin polymerization
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PROVIDER: PRJNA758977 | ENA |
REPOSITORIES: ENA
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Project description:Purpose: Evaluate how ARP2/3-coupled DSB mobility affects chromatin organization (Hi-C) and translocation frequency (HTGTS) in mouse embryonic fibroblasts (MEFs) harboring an inducible AsiSI restriction enzyme. MEF Hi-C Methods: Damaged samples were treated with 3 ug/mL doxycycline for 24 hours. For the last 6 hours of doxycycline treatment, 1 ug/mL 4-OHT was used to induce AsiSI translocation to the nucleus, triggering DSBs. Cells were co-treated with DMSO, 100 μM CK-666, or 10 μM NU7441. For DNA-PKcs inhibitor experiments, cells were pretreated with 10 μM NU7441 for 1 hour prior to induction of damage with 4OHT. 2 biological replicates were performed for each experimental condition. MEF HTGTS Methods: WT MEFs and AsiSI MEFs were treated as above. Following 6 hours treatment with dox and 4OHT, cells were lysed. For WASP inhibition, cells were treated with 3 μM wiskostatin following induction of damage. For flag-actin experiments, AsiSI-MEF cells were transfected with Flag–actinR62D–NLS 24 hours prior to induction of AsiSI expression. For cas9 experiments, WT MEF cells were transfected with sgRNA targeting Chr2 48 hours prior to cell lysis.
2022-11-14 | GSE183059 | GEO
Project description:Nuclear actin-based movements have been shown to orchestrate clustering of DNA double-strand breaks (DSBs) into homology-directed repair domains. Here we describe multiscale three-dimensional genome reorganization following DNA damage and analyze the contribution of the nuclear WASP-ARP2/3-actin pathway toward chromatin topology alterations and pathologic repair. Hi-C analysis reveals genome-wide, DNA damage-induced chromatin compartment flips facilitated by ARP2/3 that enrich for open, A compartments. Damage promotes interactions between DSBs, which in turn facilitate aberrant, actin-dependent intra- and inter-chromosomal rearrangements. Our work establishes that clustering of resected DSBs into repair domains by nuclear actin assembly is coordinated with multiscale alterations in genome architecture that enable homology-directed repair while also increasing nonhomologous end-joining-dependent translocation frequency.
| S-EPMC10104780 | biostudies-literature
Project description:Megakaryoblastic leukemia 1 (MKL1) promotes the regulation of essential cell processes, including actin cytoskeletal dynamics by co-activating serum response factor. Recently, the first human case with MKL1 deficiency, leading to a novel primary immunodeficiency, was identified. We report a second family with two siblings with a homozygous frameshift mutation in MKL1. The index case deceased as an infant from progressive and severe pneumonia by Pseudomonas aeruginosa and poor wound healing. The younger sib was preemptively transplanted shortly after birth. The immunodeficiency was marked by a pronounced actin polymerization defect and a strongly reduced motility and chemotactic response by MKL1-deficient neutrophils. Apart from the lack of MKL1, subsequent proteomic and transcriptomic analyses of patient neutrophils revealed actin and several actin-related proteins to be downregulated, confirming a role for MKL1 as transcriptional co-regulator. Degranulation was enhanced upon suboptimal neutrophil activation, while production of reactive oxygen species was normal. Neutrophil adhesion was intact but without proper spreading. The latter could explain the observed failure in firm adherence and transendothelial migration under flow conditions. No apparent defect in phagocytosis and bacterial killing was found. Also monocyte-derived macrophages showed intact phagocytosis; lymphocyte counts and proliferative capacity were normal. Non-hematopoietic primary patient fibroblasts demonstrated defective differentiation into myofibroblasts but normal migration and filamentous actin (F-actin) content, most probably due to compensatory mechanisms of MKL2, which is not expressed in neutrophils. Our findings extend current insight into the severe immune dysfunction in MKL1 deficiency, with cytoskeletal dysfunction and defective extravasation of neutrophils as most prominent features.
2020-03-16 | GSE134644 | GEO
Project description:Characterization of open chromatin sensitive to actin polymerization using DSP-MNase-DNA-seq
| PRJNA1080193 | ENA
Project description:The mechanisms underlying cancer metastasis remain poorly understood. Here, we report that TFAM deficiency rapidly and stably induced spontaneous lung metastasis in mice with liver cancer. Interestingly, unexpected polymerization of nuclear actin was observed in TFAM-knockdown HCC cells when cytoskeleton was examined. Polymerization of nuclear actin is causally linked to the high-metastatic ability of HCC cells by modulating chromatin accessibility and coordinating the expression of genes associated with extracellular matrix remodeling, angiogenesis, and cell migration. Mechanistically, TFAM deficiency blocked the TCA cycle and increased the intracellular malonyl-CoA levels. Malonylation of mDia2, which drives actin assembly, promotes its nuclear translocation. Importantly, inhibition of malonyl-CoA production or nuclear actin polymerization significantly impeded the spread of HCC cells in mice. Moreover, TFAM was significantly downregulated in metastatic HCC tissues and was associated with overall survival and time to tumor recurrence of HCC patients. Taken together, our study connects mitochondria to the metastasis of human cancer via uncovered mitochondria-to-nucleus retrograde signaling, indicating that TFAM may serve as an effective target to block HCC metastasis.
2022-06-23 | MTBLS4307 | MetaboLights
Project description:CD4 T helper cells can differentiate to several types of cells like Th1, Th2, Th17 and Treg. This process is directed by cytokines and activation of T cells by specific antigens. This process has its own plasticity and it is directed by epigenetic changes allowing cells to develop and differentiate. In this experiment, we wanted to explore the binding pattern of EZH2 in the first 24 hours of Th cells activation and differentiation side by side with VAV1 binding pattern to understand the importance of actin polymerization factors in this process.
2021-08-28 | E-MTAB-9524 | biostudies-arrayexpress
Project description:Trichloroethylene (TCE) is primarily used as an industrial degreasing agent and has been in use since the 1940s. TCE is released into the soil, surface, and groundwater. From an environmental and regulatory standpoint more than half of Superfund hazardous waste sites on the National Priority List are contaminated with TCE. Occupational exposure to TCE occurs primarily via inhalation, while environmental TCE exposure also occurs through ingestion of contaminated drinking water. Current literature links TCE exposure to various adverse health effects including cardiovascular toxicity. Current studies aiming to address developmental cardiovascular toxicity utilized rodent and avian models with the majority of studies using relatively higher parts per million (ppm; mg/L) doses. In this study to further investigate developmental cardiotoxicity of TCE, zebrafish embryos were treated with 0, 10, 100, or 500 parts per billion (ppb; μg/L) TCE during embryogenesis and/or through early larval stages. After the appropriate exposure period, angiogenesis, F-actin polymerization, and mitochondrial function were assessed. A significant dose response decrease in angiogenesis, F-actin polymerization, and mitochondrial function was observed. To further complement this data, a transcriptomic profile of zebrafish larvae was completed to identify gene alterations associated with the 10 ppb TCE exposure. Results from the transcriptomic data revealed that an embryonic TCE exposure caused significant changes in genes associated with cardiovascular disease, cancer, and organismal injury and abnormalities with a number of targets in the FAK signaling pathway. Overall, results from our study further support TCE as a developmental cardiovascular toxicant and continued priority for environmental regulation.
2016-02-01 | GSE72918 | GEO
Project description:MKL1 deficiency results in a severe neutrophil motility defect due to impaired actin polymerization
| PRJNA555994 | ENA
Project description:Mitochondrial damage (MtD) represents a dramatic change in cellular homeostasis, necessitating metabolic changes and stimulating mitophagy. One rapid response to MtD is rapid peri-mitochondrial actin polymerization, termed ADA (acute damage-induced actin). The activation mechanism for ADA is unknown. Here, we use mitochondrial depolarization or the complex I inhibitor metformin to induce ADA. We show that two parallel signaling pathways are required for ADA. In one pathway, increased cytosolic calcium activates in turn PKC-β, Rac, WAVE regulatory complex, and Arp2/3 complex. In the other pathway, a drop in cellular ATP activates in turn AMPK (through LKB1), Cdc42, and FMNL formins. We also identify putative guanine nucleotide exchange factors for Rac and Cdc42, Trio and Fgd1 respectively, whose phosphorylation states increase upon mitochondrial depolarization and whose suppression inhibits ADA. The depolarization-induced calcium increase is dependent on the mitochondrial sodium-calcium exchanger NCLX, suggesting initial mitochondrial calcium efflux. We also show that ADA inhibition results in enhanced mitochondrial shape changes upon mitochondrial depolarization, suggesting that ADA inhibits these shape changes. These depolarization-induced shape changes are not fragmentation but a circularization of the inner mitochondrial membrane, dependent on the inner mitochondrial membrane protease Oma1. ADA inhibition increases proteolytic processing of an Oma1 substrate, the dynamin GTPase Opa1. These results show that ADA requires the combined action of Arp2/3 complex and formin proteins to polymerize a network of actin filaments around mitochondria, and that the ADA network inhibits the rapid mitochondrial shape changes that occur upon mitochondrial depolarization.
2022-03-15 | PXD031699 | Pride
Project description:Spermatogenesis is a biological process within the testis that produces haploid spermatozoa for the continuity of species. Sertoli cells are somatic cells in the seminiferous epithelium that orchestrate spermatogenesis. Cyclic reorganization of Sertoli cell actin cytoskeleton is vital for spermatogenesis but the underlying mechanism remains largely unclear. Here we report that RNA-binding protein PTBP1 controls Sertoli cell actin cytoskeleton reorganization by programming alternative splicing of actin cytoskeleton regulators. This splicing control enables ectoplasmic specializations, the actin-based adhesion junctions, to maintain the blood-testis barrier and support spermatid transport and transformation. Of particular, we show that PTBP1 promotes actin bundle formation by repressing the inclusion of exon 14 of Tnik, a kinase present at the ectoplasmic specialization. Our results thus reveal a novel mechanism wherein Sertoli cell actin cytoskeleton dynamics is controlled post-transcriptionally by utilizing functionally distinct isoforms of actin regulatory proteins and PTBP1 is a key player in generating such isoforms.
2024-07-31 | GSE267924 | GEO