A5057998870- DNA Repair Mechanisms
- DNA and Nucleic Acid Chemistry
- Advanced biosensing and bioanalysis techniques
- Cancer therapeutics and mechanisms
- Genomics and Chromatin Dynamics
- Click Chemistry and Applications
- CRISPR and Genetic Engineering
- PARP inhibition in cancer therapy
- RNA Interference and Gene Delivery
- Chemical Synthesis and Analysis
- RNA Research and Splicing
- Metal-Catalyzed Oxygenation Mechanisms
- Cancer-related Molecular Pathways
- Computational Drug Discovery Methods
- Synthesis and Characterization of Pyrroles
- Mechanisms of cancer metastasis
- Nuclear Structure and Function
- Ubiquitin and proteasome pathways
- Epigenetics and DNA Methylation
- RNA and protein synthesis mechanisms
- Mitochondrial Function and Pathology
- Chromosomal and Genetic Variations
- Cyclization and Aryne Chemistry
- Microtubule and mitosis dynamics
- Biochemical Acid Research Studies
Institut de Pharmacologie et de Biologie Structurale
2014-2024
Université de Toulouse
2014-2024
Université Toulouse III - Paul Sabatier
2009-2024
Centre National de la Recherche Scientifique
2014-2024
La Ligue Contre le Cancer
2014-2024
University of Cambridge
2010-2015
Wellcome Trust
2013-2015
The Gurdon Institute
2012-2015
Inserm
2002
Down-regulation and mutations of the nuclear-architecture proteins lamin A C cause misshapen nuclei altered chromatin organization associated with cancer laminopathies, including premature-aging disease Hutchinson-Gilford progeria syndrome (HGPS). Here, we identified small molecule "Remodelin" that improved nuclear architecture, organization, fitness both human A/C-depleted cells HGPS-derived patient decreased markers DNA damage in these cells. Using a combination chemical, cellular, genetic...
DNA double-strand breaks (DSBs) are the most toxic of all genomic insults, and pathways dealing with their signaling repair crucial to prevent cancer for immune system development. Despite intense investigations, our knowledge these has been technically limited by inability detect main factors at DSBs in cells. In this paper, we present an original method that involves a combination ribonuclease- detergent-based preextraction high-resolution microscopy. This allows direct visualization...
We previously identified the heterogeneous ribonucleoprotein SAF-A/hnRNP U as a substrate for DNA-PK, protein kinase involved in DNA damage response (DDR). Using laser micro-irradiation human cells, we report here that SAF-A exhibits two-phase dynamics at sites of damage, with rapid and transient recruitment followed by prolonged exclusion. corresponds to its binding Poly(ADP-ribose) while exclusion is dependent on activity ATM, ATR DNA-PK reflects dissociation from chromatin associated...
Although accumulation of DNA damage and genomic instability in resting cells can cause neurodegenerative disorders, our understanding how transcription produces double-strand breaks (DSBs) is limited. Transcription-blocking topoisomerase I cleavage complexes (TOP1ccs) are frequent events that prime DSB production non-replicating cells. Here, we report a mechanism their formation by showing they arise from two nearby single-strand (SSBs) on opposing strands: one SSB the removal...
Abstract Repair of single-ended DNA double-strand breaks (seDSBs) by homologous recombination (HR) requires the generation a 3′ single-strand overhang exonuclease activities in process called resection. However, it is anticipated that highly abundant end-binding protein Ku sequesters seDSBs and shields them from activities. Despite pioneering works yeast, unclear how mammalian cells counteract at to allow HR proceed. Here we show human cells, ATM-dependent phosphorylation CtIP epistatic...
The activities of many DNA-repair proteins are controlled through reversible covalent modification by ubiquitin and ubiquitin-like molecules. Nonhomologous end-joining (NHEJ) is the predominant DNA double-strand break (DSB) repair pathway in mammalian cells initiated DSB ends being recognized Ku70/Ku80 (Ku) heterodimer. By using MLN4924, an anti-cancer drug clinical trials that specifically inhibits conjugation protein, NEDD8, to target proteins, we demonstrate NEDD8 accumulation at...
G-quadruplexes (G4) are non-canonical DNA structures found in the genome of most species including human. Small molecules stabilizing these structures, called G4 ligands, have been identified and, for some them, shown to induce cytotoxic double-strand breaks. Through use an unbiased genetic approach, we identify here topoisomerase 2α (TOP2A) as a major effector cytotoxicity induced by two clastogenic pyridostatin and CX-5461, latter molecule currently undergoing phase I/II clinical trials...
Nonhomologous end joining is a critical mechanism that repairs DNA double-strand breaks in human cells. In this work, we address the structural and functional role of accessory protein PAXX [paralog x-ray repair cross-complementing 4 (XRCC4) XRCC4-like factor (XLF)] mechanism. Here, report high-resolution cryo-electron microscopy (cryo-EM) crystallography structures C-terminal Ku-binding motif bound to Ku70/80 cryo-EM two alternate DNA-dependent kinase (DNA-PK) end-bridging dimers, mediated...
Abstract Two DNA repair pathways operate at double strand breaks (DSBs): non-homologous end-joining (NHEJ), that requires two adjacent ends for ligation, and homologous recombination (HR), resects one invasion of a duplex. Faithful replicative single-ended DSBs (seDSBs) is mediated by HR, due to the lack second end end-joining. ATM stimulates resection such through multiple mechanisms including CtIP phosphorylation, which also promotes removal DNA-ends sensor NHEJ protein Ku. Here, using new...
Abstract Centromeres are defined by chromatin containing the histone H3 variant CENP-A assembled onto repetitive α-satellite sequences, which actively transcribed throughout cell cycle. play an essential role in chromosome inheritance and genome stability through coordinating kinetochores assembly during mitosis. Structural functional alterations of centromeres cause aneuploidy aberrations can induce death. In human cells, tumor suppressor BRCA1 associates with centromeric absence exogenous...
Repair of DNA double-strand breaks by the non-homologous end-joining pathway is initiated binding Ku to ends. Multiple proteins load onto linear DNAs in vitro. However, cells, loading limited ∼1-2 molecules per end. The mechanisms enforcing this limit are currently unclear. Here, we show that catalytic subunit DNA-dependent protein kinase (DNA-PKcs), but not its activity, required prevent excessive entry into chromatin. accumulation further restricted two mechanisms: a...
The nuclear envelope (NE) is important for cellular health as it protects and organizes the genome. NE dynamics various processes including cell growth, migration removal of defective components. In extreme cases, can rupture leading to exchange material between interior cytoplasm. Rapid repair initiated minimize effect on While our understanding machinery involved in this process increasing, a lot still unknown about events up rupture. Interestingly, biomolecular condensates have recently...
Translocation of DNA and RNA polymerases along their duplex substrates results in supercoiling. This torsional stress promotes the formation plectonemic structures, including three-way junction (TWJ), which can block transactions lead to damage. While cells have evolved multiple mechanisms prevent accumulation such stabilizing TWJ through ad hoc ligands offer an opportunity trigger damage with high levels transcription replication, as cancer cells. Here, we develop a series azacryptand-based...
Abstract G-quadruplexes (G4) are non-canonical secondary structures consisting in stacked tetrads of hydrogen-bonded guanines bases. An essential feature G4 is their intrinsic polymorphic nature, which characterized by the equilibrium between several conformations (also called topologies) and presence different types loops with variable lengths. In cells, functions rely on protein or enzymatic factors that recognize promote resolve these structures. order to characterize new G4-dependent...
Aiming to identify novel phosphorylation sites in response DNA double-strand breaks (DSB) inducers, we have isolated a site on KU70. Unexpectedly, rabbit antiserum raised against this cross-reacted with 120 kDa protein cells treated by DSB inducers. We identified as SAF-A/hnRNP U, an abundant and essential nuclear containing regions binding or RNA. The was mapped at S59 position sequence context favoring "S-hydrophobic" consensus model for DNA-PK vivo. This exclusively phosphorylated In...
The human genome is replete with repetitive DNA sequences that can fold into thermodynamically stable secondary structures such as hairpins and quadruplexes. Cellular enzymes exist to cope these whose accumulation would result in damage through interference transactions transcription replication. Therefore, the chemical stabilization of offers an attractive way foster transaction-associated damages trigger cell death proliferating cancer cells. While much emphasis has been recently given...
Scaffold attachment factor A (SAF-A), also called heterogenous nuclear ribonuclear protein U (hnRNP-U), is phosphorylated on serine 59 by the DNA-dependent kinase (DNA-PK) in response to DNA damage. Since SAF-A, DNA-PK catalytic subunit (DNA-PKcs), and phosphatase 6 (PP6), which interacts with DNA-PKcs, have all been shown roles mitosis, we asked whether DNA-PKcs phosphorylates SAF-A mitosis. We show that phosphorylation requires polo-like 1 (PLK1) rather than PLK1 nocodazole-treated cells,...
Abstract DNA is intrinsically dynamic and folds transiently into alternative higher-order structures such as G-quadruplexes (G4s) three-way junctions (TWJs). G4s TWJs can be stabilised by small molecules (ligands) that have high chemotherapeutic potential, either standalone damaging agents or combined in synthetic lethality strategies. While previous approaches claimed to use ligands specifically target TWJs, we report here on a new approach which targeting both vitro demonstrate cellular...