Dissertationen zum Thema „Réparation de l'ADN mitochondrial“
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Wallet, Clementine. „L'hélicase RECG1, un facteur-clé dans le maintien et la ségrégation de l'ADN mitochondrial d'Arabidopsis thaliana“. Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAJ016/document.
Der volle Inhalt der QuelleThe mitochondrial DNA (mtDNA) of flowering plants is characterized by the recombination activities that modulate its structure. These activities are required for the mtDNA maintenance, and drive its rapid structural evolution. The factors that control recombination are therefore essential for plant mtDNA stability. During my PhD, I identified and characterized two DNA helicases that are present in the organelles of Arabidopsisthaliana. One is the homologue of a bacterial helicase involved in transcription-coupled repair. Its role in the plant organelles is still not determined. The other one, the RECG1 helicase, has roles in recombination dependent repair, the surveillance of ectopic recombination involving short repeated sequences, and also the segregation of the mtDNA. We have found that in the absence of RECG1 there is loss of recombination control resulting in the occurrence of alternative versions of the mtDNA generated by recombination. The analysis oftheir segregation, induced by RECG1, allowed us to build a model to how new stable mtDNA configurations are generated by the stoichiometric shift of mtDNA sub-genomes. This work allowed us to better understand the recombination and segregation mechanisms that modulate the Arabidopsis mtDNA
Kubilinskas, Rokas. „MitoTALENs to explore mitochondrial DNA repair and segregation“. Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAJ014.
Der volle Inhalt der QuelleFor long, the plant mitochondrial genome (mtDNA) was not amenable to manipulation, until recent advancements in genome engineering using Transcription Activator-Like Effector Nucleases (TALEN). In this work I used TALENs specifically targeted to mitochondria (mitoTALENs) to study plant mtDNA repair and segregation. MitoTALEN constructs were transformed into the background of 10 different Arabidopsis thaliana mutant lines, deficient in various factors involved in plant mitochondrial repair by homologous recombination. The resulting lines were analysed by Illumina sequencing and qPCR approaches. In wild type plants, the mtDNA double-strand-break (DSB) induced by MitoTALENs was repaired by homologous recombination, resulting in the replacement of the region containing the DSB by a distal unaffected sequence of the mtDNA, flanked by the same set of repeated sequences. In mutants deficient in repair factors, repair could shift to alternative pathways, such as Single-Strand Annealing (SSA) and Microhomology-mediated recombination (MHMR). Furthermore, in some mutants, the data revealed no evidence of DSB repair, but rather suggested that plants deficient in key repair factors could survive by reconstituting an alternative viable mitochondrial genome, from pre-existing autonomously replicating sub-genomes
Moretton, Amandine. „Mécanismes de maintenance de l'intégrité de l'ADN mitochondrial humain suite à des cassures double-brin“. Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC047/document.
Der volle Inhalt der QuelleMitochondria are organelles that possess their own genome, the mitochondrial DNA (mtDNA). Repair of oxidative damages, defective replication, or various exogenous sources, such as chemotherapeutic agents or ionizing radiations, can generate double-strand breaks (DSBs) in mtDNA. MtDNA encodes for essential proteins involved in ATP production and maintenance of integrity of this genome is thus of crucial importance. Mutations in mtDNA are indeed found in numerous pathologies such as mitochondrial myopathies, neurodegenerative disorders or cancers. However, the mechanisms involved in mtDNA maintenance after DSBs remain unknown.To elucidate this question, we have generated mtDNA DSBs using a human inducible cell system expressing the restriction enzyme PstI targeted to mitochondria. Using this system, we could not find any support for DSBs repair of mtDNA. Instead we observed a loss of the damaged mtDNA molecules and a severe decrease in mtDNA content, followed by reamplification of intact mtDNA molecules. We have demonstrated that none of the known mitochondrial nucleases are involved in mtDNA degradation and that DNA loss is not due to autophagy, mitophagy or apoptosis but to a selective mechanism. Our study suggests that a still uncharacterized pathway for the targeted degradation of damaged mtDNA in a mitophagy/autophagy-independent manner is present in mitochondria, and might provide the main mechanism used by the cells to deal with DSBs. Global approaches are ongoing to identify proteins involved in degradation of damaged mtDNA following DSBs, mainly an RNAi screen targeting 80 nucleases. In parallel we are interested in a family of phosphohydrolases named Nudix and their putative protective role in sanitizing the nucleotides pool in mitochondria
Martinet, Pervenche. „Peau et anomalies de la réparation de l'ADN aux ultraviolets : à propos d'une observation associant dyschromie, syndrome cérébelleux et dysfonctionnement mitochondrial“. Aix-Marseille 2, 1994. http://www.theses.fr/1994AIX20831.
Der volle Inhalt der QuelleIqbal, Rana khalid. „Approches biotechnologiques de l'expression et de la diversité du génome mitochondrial des plantes“. Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAJ035/document.
Der volle Inhalt der QuelleThe mitochondrial DNA of plants is dynamic and its expression is complex. Using a strategy based on the natural import of nuclear-encoded transfer RNAs from the cytosol, we targeted to mitochondria in Arabidopsis thaliana the orf77 RNA characteristic for S-CMS in maize and we analyzed the effects on the transcriptome. The results showed that the mitochondrial transcriptome is tighly regulated during plant development and is strongly buffered at early stages. Mitochondrial targeting of orf77 also triggered a cross-talk with the nucleus. On the other hand, DNA replication and repair in plant mitochondria involve active recombination controled by nuclear-encoded factors. We identified a new member of this set of factors, the 5'-3' exonuclease potentially responsible for the resection of DNA ends in recombination-mediated repair of double-strand breaks. As a whole, the results open prospects for generating mitochondrial genetic diversity and creating CMS lines with agronomical interest
Boesch, Pierre. „Caractérisation d'un mécanisme de réparation de l'ADN par excision de base dans les mitochondries des cellules végétales“. Université Louis Pasteur (Strasbourg) (1971-2008), 2005. http://www.theses.fr/2005STR13181.
Der volle Inhalt der QuelleMitochondria possess their own DNA (mtDNA) and are a major source for Reactive Oxygen Species (ROS) production. Due to its close proximity to the ROS source the mtDNA is a likely to be oxidized. 8-oxo-guanine (8oxoG) and uracile are the most studied oxidative lesion and are repaired by the Base Excision Repair (BER) pathway. This DNA repair pathway is also the only one found with absolute certainty in mitochondria. As the question of DNA repair in plant’s organelles remains open our laboratory has initiated a study whose aim was to show whether mitochondria and chloroplast are able to repair DNA or not. In a first set of in vitro experiments we have shown that plant organelle do actually harbor DNA glycosylase and AP endonuclease activities, and that some part of each activities is somehow present in a membrane associated fashion. The second set of in organello experiments has enable us to show that a DNA carrying uracile can be imported and fully repaired in plant mitochondria. So, these organelles do actually have also DNA repair synthesis and ligase activity. The presence of a complete BER pathway in plant mitochondria is thus undoubtful, but the question of its association with the membrane remains open and the protein involved in this pathway should still be identified
Rageul, Julie. „Rôles d'ERCC1, une protéine clé de la réparation de l'ADN, dans la progression du cycle cellulaire et la survie des cellules humaines, tumorales ou non“. Rennes 1, 2011. http://www.theses.fr/2011REN1B081.
Der volle Inhalt der QuelleERCC1-XPF (Excision Repair Cross Complementing gene 1/Xeroderma Pigmentosum group F) is a heterodimeric endonuclease involved in many DNA repair systems. Phenotypes of ERCC1 deficiency in diverse organisms suggest that this protein may have an additional role in the regulation of cell cycle progression. To evaluate this hypothesis in human tumoral and non-tumoral cell lines, we knocked-down ERCC1 by RNA interference (ERCC1KD). Our results have shown that ERCC1KD cells become multinucleated, not only in tumoral cells but also in non-tumoral cells and regardless of tissue type. These multinucleated cells accumulate nuclei through abnormal mitoses ending by a defective cytokinesis. In addition, when mitotic abnormalities are too drastic, ERCC1KD cells die in mitosis, and this is highly reminiscent of mitotic catastrophe. In an original way, cells knocked-down for XPF do not share this phenotype of multinucleation, suggesting for the first time that ERCC1 could bear a new role, independently of its known DNA repair activity. Furthermore, we have provided evidence suggesting that this new role of ERCC1 could potentially involve the oxidant/antioxidant balance and could be linked to a mitochondrial function. This ERCC1 new role may be crucial for development, growth, proliferation and cell survival. Finally, it may be conceivable that ERCC1 might become a new promising therapeutic target for cancer treatment
Paraf, François. „Gènes de réparation de l'ADN et Cancers Colorectaux“. Université de Limoges. Faculté de médecine et de pharmacie, 2001. http://www.theses.fr/2001LIMO102B.
Der volle Inhalt der QuelleEot-Houllier, Grégory. „Réparation in vitro de sites multilésés de l'ADN“. Paris 11, 2005. http://www.theses.fr/2005PA11T018.
Der volle Inhalt der QuelleJobin-Robitaille, Olivier. „Dynamique chromatinienne dans la réparation de l'ADN : analyse fonctionnelle du complexe histone acétyltransférase NuA4 dans la réparation des dommages à l'ADN“. Thesis, Université Laval, 2005. http://www.theses.ulaval.ca/2005/22935/22935.pdf.
Der volle Inhalt der QuelleInscrit au Tableau d'honneur de la Faculté des études supérieures
Tremblay, Sébastien. „L'oxydation de la cytosine dans l'ADN et sa réparation“. Thèse, Université de Sherbrooke, 2004. http://savoirs.usherbrooke.ca/handle/11143/4199.
Der volle Inhalt der QuelleMorelle, Sandrine. „Identification d'un régulon de Neisseria meningitidis contrôlé par l'interféron avec les cellules de l'hôte“. Paris 5, 2003. http://www.theses.fr/2003PA05N108.
Der volle Inhalt der QuelleNeisseria meningitidis (Nm) is a human extracellular pathogene that is responsible for septicaemia and meningitis, especially in children. Bacterial adhesion to human cells is the first step of infection. The analysis of the genomic sequence of Neisseria meningitidis Z2491 revealed the presence of many repeats, homologous to promotor, present upstream of 16 ORF. It has been demonstrated that these ORF constitute a regulon whose expression is induced by cell contact. Subsequent mutational analysis was performed by transposition in vitro to address the role of these genes during meningococcal-cell interactionOne of these frames is homologous to Escherichia coli exonuclease VII, which is implicated in DNA repair. The participation of this gene in meningococcal DNA repair was demonstrated by increased sensivity.
Bourdon, Alice. „Ribonucléotide réductase et synthèse de l'ADN mitochondrial“. Paris 5, 2009. http://www.theses.fr/2009PA05T006.
Der volle Inhalt der QuelleMitochondrial DNA (mtDNA) depletions are characterized by a decreased number of mtDNA molecules and constitute a major cause of respiratory chain deficiency. This work allowed us to identify a new nuclear gene of mtDNA depletion associated with a severe encephalomyopathy leading to death in the first months of age. This gene encodes a small ribonucleotide reductase (RNR) subunit p53R2 which is a target of the transcription factor p53. RNR catalyses the reduction of the nucleotides into their corresponding desoxyribonucleotides, which is the rate limiting step for DNA synthesis. The second part of this work focuses on the role of p53R2 in mtDNA replication studying its subcellular localization and the expression of the subunits of RNR in several mouse tissues during development
Biju, Duval Christophe. „Diversité de l'ADN mitochondrial chez les lagomorphes“. Paris 6, 1992. http://www.theses.fr/1992PA066046.
Der volle Inhalt der QuelleCastaing, Bertrand. „La formamidopyrimidine-ADN glycosylase, un enzyme de reparation de l'ADN chez E. Coli : étude de son interaction avec l'ADN“. Aix-Marseille 2, 1993. http://www.theses.fr/1993AIX22035.
Der volle Inhalt der QuelleBoussicault, Fabien. „Réparation de modèles de lésions photoinduites de l'ADN. Approches électrochimiques“. Phd thesis, Université Paris-Diderot - Paris VII, 2006. http://tel.archives-ouvertes.fr/tel-00109091.
Der volle Inhalt der QuelleL'étude par voltamétrie cyclique de modèles des lésions de type cyclobutane nous a permis d'une part de mimer l'étape clef de la réparation enzymatique (transfert d'électron dissociatif) et d'autre part de suivre dans le temps la réparation des lésions modèles par la photolyase ADN d'Escherichia coli. A partir des résultats obtenus, nous avons pu discuter le mécanisme de réparation, en particulier le caractère concerté ou séquentiel des réactions à l'oeuvre.
Le mécanisme de réparation des adduits (6-4) n'est pas encore élucidé mais une voie possible implique comme précédemment un transfert d'électron couplé à la coupure de deux liaisons vers la forme fermée des lésions (oxétanes). L'étude par voltamétrie cyclique d'une part de la réduction et de l'oxydation d'oxétanes modèles et d'autre part de leur réparation par la photolyase ADN d'E. coli nous a permis de rassembler une série de preuves expérimentales qui confirment le mécanisme initialement proposé et permettent de mieux le comprendre.
Slade, Dea. „Mécanisme moléculaire de la réparation de l'ADN chez Deinococcus radiodurans“. Paris 6, 2009. http://www.theses.fr/2009PA066758.
Der volle Inhalt der QuelleDEGOUL, FRANCOISE. „Mutations de l'adn mitochondrial dans differentes myopathies humaines“. Clermont-Ferrand 2, 1991. http://www.theses.fr/1991CLF21276.
Der volle Inhalt der QuelleRocher, Christophe. „Anomalies de l'ADN mitochondrial et métabolisme mitochondrial : Mécanismes des déplétions et des délétions“. Bordeaux 2, 2001. http://www.theses.fr/2001BOR28910.
Der volle Inhalt der QuelleOne of the fundamental problems of the study of mitochondrial metabolism integration in cellular metabolism is to understand how mitochondrial metabolism is controlled (regulated) ? The subject of this thesis concerns this topic and tries to answer the two following questions : 1- What are the repercussions of a mitochondrial DNA (mtDNA) amount variation at the level of the energy metabolism ? We used two models which are : (i) a lymphoblastoid cell line coming from a patient for whom a 99 % decrease of the muscle mtDNA amount was observed (depletion), but also (ii) a series of stable mtDNA depleted cell lines obtained by treatment of a control one with nucleotides analogues (AZT and ddC). The results clearly indicate that cellular mtDNA amount is one important parameter in the regulation of oxidative phosphorylations. Indeed, despite the high copy number of mtDNA, a small decrease in its content has severe implications on mitochondrial bioenergetics. Consequently, the quantity of mtDNA in the cell is a parameter to take into account for the study of mitochondrial pathologies as well as the nature or the heteroplasmlic level of a mtDNA mutation. 2- What are the molecular mechanisms involved in the generation of human mitochondrial DNA rearrangements, such as large-scale deletions ? Some mitochondrial pathologies areare due to such reorganizations of mtDNA and different mechanisms have been proposed to explain these rearrangements. The mechanism of slipped mispairing has been proposed but no molecular bases are described. The results we obtained show that the formation of a triple helix could be involved in the generation of mtDNA deletions as well as partial duplications or triplications
Dendouga, Najoua. „Identification et caractérisation d'une enzyme de réparation de l'ADN chez Toxoplasma Gondii“. Lille 2, 2002. http://www.theses.fr/2002LIL2MT02.
Der volle Inhalt der QuelleLegros, Frédéric. „Étude de la dynamique du compartiment mitochondrial et des mutations hétéroplasmiques de l'ADN mitochondrial“. Paris 7, 2002. http://www.theses.fr/2002PA077109.
Der volle Inhalt der QuelleGarnery, Lionel. „Variabilité de l'ADN mitochondrial de l'abeille domestique : Implications phylogénétiques“. Paris 6, 1992. http://www.theses.fr/1992PA066487.
Der volle Inhalt der QuelleSarzi, Emmanuelle. „Caractérisation génétique et phénotypique des déplétions de l'ADN mitochondrial“. Paris 5, 2008. http://www.theses.fr/2008PA05T048.
Der volle Inhalt der QuelleMitochondrial diseases are a common group of metabolism pathologies. Nowadays, they represent more than 17% of our clinical consultations. Multiple respiratory chain deficiency account for an important number of mitochondrial disease and are characterised by a multi-systemic organ involvement leading to early death. Since these last 15 years, we have recruited a large number of patients with multiple respiratory chain deficiency. In 2001, it has been shown that a mtDNA quantitative anomaly was at the origin of this defect also named mtDNA depletions. The large number of patients with multiple respiratory chain deficiency and the weak yield of molecular diagnosis prompt us to consider mtDNA depletion as a cause of multiple respiratory chain deficiency. The aim of this work was firstly to estimate the incidence of mtDNA depletion in our series of multiple respiratory chain cases. Then, we characterised the genetic and phenotypic features of mtDNA depletions. Finaly, the study of one family among our consanguineous and/or multiplex patients allowed us to identify a new gene responsible for mtDNA depletions associated with a hepatocerebral failure. This gene also named PEO1 encodes for the mitochondrial Twinkle helicase which has been ever known to cause adult onset PEO in a dominant transmission. Finally, we have studied another consanguineous family with multiple respiratory chain deficiency and hepatic failure. This work allowed us to improve the genetic counselling in our laboratory especially for all patients with multiple respiratory chain deficiency associated with a mtDNA depletion
Al, Amir Dache Zahra. „Étude de la structure de l'ADN circulant d'origine mitochondriale“. Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTT059.
Der volle Inhalt der QuellePlasma transports blood cells with a mixture of compounds, including nutrients, waste, antibodies, and chemical messengers...throughout the body. Non-soluble factors such as circulating DNA and extracellular vesicles have recently been added to the list of these components and have been the subject of extensive research due to their role in intercellular communication. Circulating DNA (cirDNA) is composed of cell-free and particle-associated DNA fragments, which can be released by all cell types. cirDNA is derived not only from genomic DNA but also from extrachromosomal mitochondrial DNA. Numerous studies carried out lately indicate that the quantitative and qualitative analysis of cirDNA represents a breakthrough in clinical applications as a non-invasive biomarker for diagnosis, prognosis and therapeutic follow-up. However, despite the promising future of cirDNA in clinical applications, particularly in oncology, knowledge regarding its origins, composition and functions, that could considerably optimize its diagnostic value, is still lacking.The main goal of my thesis was to identify and characterize the structural properties of extracellular DNA of mitochondrial origin. By examining the integrity of this DNA, as well as the size and density of associated structures, this work revealed the presence of dense particles larger than 0.2 µm containing whole mitochondrial genomes. We characterized these structures by electron microscopy and flow cytometry and identified intact mitochondria in the extracellular medium in vitro and ex vivo (in plasma samples from healthy individuals). Oxygen consumption by these mitochondria was detected by the Seahorse technology, suggesting that at least some of these intact extracellular mitochondria may be functional.In addition, I contributed to other studies carried out in the team, such as studies aiming at evaluating (1) the influence of pre-analytical and demographic parameters on the quantification of nuclear and mitochondrial cirDNA on a cohort of 104 healthy individuals and 118 patients with metastatic colorectal cancer, (2) the influence of hypoxia on the release of cirDNA in vitro and in vivo, and (3) the potential of cirDNA analysis in the early detection and screening of cancer.This manuscript present a recent review on cirDNA and its different mechanisms of release, which go hand in hand with the structural characterization of this DNA, its functional aspects and its clinical applications. In addition, this thesis provides new knowledge on the structure of extracellular mitochondrial DNA and opens up new avenues for reflection, particularly on the potential impact that could have those circulating mitochondria on cell-cell communication, inflammation and clinical applications
Lourdin, Morgane. „Etudes biochimiques et structurales de la réparation des lésions multiples de l'ADN“. Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENV007/document.
Der volle Inhalt der QuelleNonnekens, Julie. „Bases moléculaires des syndromes de déficiences en transcription et réparation de l'ADN“. Toulouse 3, 2013. http://www.theses.fr/2013TOU30045.
Der volle Inhalt der QuelleXeroderma pigmentosum, Cockayne syndrome and trichothiodystrophy are rare autosomal recessive disorders caused by mutations in proteins which are implicated in nucleotide excision repair and transcription. In this thesis, we examined different cellular aspects to better understand the molecular mechanisms underlying the pathophysiology of these severe diseases. First, we describe the role of TFIIH and XPG in ribosome biogenesis: we characterized the function of TFIIH as a RNA polymerase I transcription factor functioning in elongation and described a novel role for XPG during early ribosomal RNA maturation. Next, we examined the DNA repair pathway responsible for repair of the transcribed ribosomal RNA. Finally, we used a novel in vivo tripartite split-GFP system to investigate protein-protein interactions within TFIIH
Larmony, Sharon. „Identification des protéines impliquées dans la réparation de l'ADN chez Sulfolobus solfataricus“. Versailles-St Quentin en Yvelines, 2010. http://www.theses.fr/2007VERS0029.
Der volle Inhalt der QuelleS. Solfataricus est un Archaea thermoacidophile vivant à 80°C, température où la fréquence des dommages de l'ADN est fortement augmentée ce qui suppose qu’il possède un système de réparation de son génome très efficace. La réponse cellulaire de S. Solfataricus aux rayonnements gamma et aux UV a été suivie par une approche de protéomique différentielle. Nous avons montré que S. Solfataricus résiste à des doses allant jusqu'à 1000 Gray alors qu’il ne possède aucun système de protection des cassures double-brin de son ADN. La cinétique de réparation de l’ADN indique qu’il dispose d’un système de réparation efficace. Dans son protéome, nous avons identifié par spectrométrie de masse 17 protéines présentant des variations après irradiation, dont les protéines de réplication PCNA-2 et Cdc6-2. Enfin, par marquage spécifique des protéines, nous avons visualisé une variation importante de la dynamique des protéines de cellules irradiées. Pour visualiser clairement la réponse de S. Solfataricus, nous avons utilisé une souche infectée par le virus tempéré SSV1. La comparaison des protéomes nous a permis d’identifier 23 protéines par spectrométrie de masse, dont une partie intervenant dans le stress oxydant et le métabolisme de l’ADN. Ainsi, nos travaux montrent que, quelle que soit la nature des dommages subis par S. Solfataricus, son protéome subit très peu de variations. Les protéines de réparation pourraient être recrutées aux sites de lésions par modifications post-traductionnelles et/ou par relocalisation dans la cellule pour une réparation rapide et efficace des lésions de l’ADN
Kieffer, Kyong-Rim. „Stimulation de la réparation de l'ADN par des activateurs de la transcription“. Université Louis Pasteur (Strasbourg) (1971-2008), 2002. http://www.theses.fr/2002STR13085.
Der volle Inhalt der QuelleEukaryotic genes are contained within a higher order complex of DNA and histones called chromatin. Although packaging of DNA into chromatin provides the means for compaction of the entire genome to fit in the nucleus, it restricts the access of the many regulatory proteins required for essential biological processes such as DNA replication, transcription, and recombination. The chromatin, however, is not a static structure, but rather a dynamic assembly that condenses and decondenses (remodeling) in response to specific signals during cell life. Chromatin remodeling requires a specific set of enzymes that modify the nucleosome, the building block of chromatin. These enzymes fall into two classes: the first includes ATP-dependent chromatin remodeling activities that use energy derived from ATP hydrolysis to alter nucleosomal structure and/or arrangement, whereas the second class includes enzymes that add acetyl groups to the histone N termini. This thesis has described that DNA repair is also hindered by chromatin structure and requires a subset of chromatin remodeling enzymes from each class to optimally occur. In the promoter region, chromatin remodeling enzymes are dictated by sequence-specific activators, resulting in facilitated damage removal in the proximity of transcription initiation site. The mechanism of this preferential repair is independent of transcription machinery and transcription per se, although two events pass on the same template. Furthermore, transcriptionally inactive activator accomplishes the stimulation of repair by binding to its cognate sequences. It is likely that the function of activators is dual : (i) they help to derepress chromatin, a step common to DNA processes, (ii) in parallel or subsequently, and possibly in a cooperative manner according to activities demanded by the surrounding DNA, they recruit specific factors involved in transcription, DNA repair or replication
NELSON, ISABELLE. „Etude de l'organisation de l'adn mitochondrial dans les pathologies neuromusculaires“. Rennes 1, 1991. http://www.theses.fr/1991REN10073.
Der volle Inhalt der QuelleBarome, Pierre-Olivier. „Phylogeographie du genre acomys (rodentia, muridae) fondee sur l'adn mitochondrial“. Paris 11, 1998. http://www.theses.fr/1998PA112350.
Der volle Inhalt der QuelleReynier, Pascal. „Etude des délétions de l'ADN mitochondrial dans diverses maladies musculaires“. Aix-Marseille 2, 1995. http://www.theses.fr/1995AIX22061.
Der volle Inhalt der QuelleJacquet, Karine. „Fonction et régulation du complexe acétyltransférase TIP60 au cours de la réponse aux dommages de l'ADN“. Doctoral thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/27557.
Der volle Inhalt der QuelleAuriol, Jérôme. „Etude fonctionnelle du facteur de transcription/réparation TFIIH : rôles dans le mécanisme de réparation de l'ADN par excision de nucléotides“. Université Louis Pasteur (Strasbourg) (1971-2008), 2002. http://www.theses.fr/2002STR13178.
Der volle Inhalt der QuelleTFIIH is a multiprotein complex involved in transcription of class II and class I genes, and in nucleotide excision repair (NER). The cellular importance of this complex is illustrated by genetic disorders associated with mutations in two subunits of TFIIH, the XPB and XPD helicases. Those helicases are essentials for transcriptional and DNA repair mechanisms. During my PhD studies, we became interested in the function of TFIIH in NER. We studied the molecular consequences of an XPB mutation which change the last 40 C-terminal amino acids. Mutation disrupts TFIIH activity both in transcription and in repair. This mutant allowed us to identify an XPB phosphorylation site required for the cellular functions of TFIIH. Moreover, we isolated a complex containing TFIIH, RNA polymerase I and two repair proteins XPG and CSB. This complex is involved in ribosomal RNA synthesis. We show that mutations within the CSB protein destabilized the complex. This is also true for mutations within XPB and XPD, arguing for the biological significance of this complex. Finally, in order to study the regulation of TFIIH expression, we study the organisation of murine gene coding for p62 subunit as well as its promoter
Sattler, Ulrike. „Analyse des dommages oxydatifs de l'ADN et de leurs effets biologiques“. Toulouse 3, 2002. http://www.theses.fr/2002TOU30052.
Der volle Inhalt der QuellePardo, Benjamin. „Protection de l'intégrité des télomères chez la levure“. Paris 11, 2006. http://www.theses.fr/2006PA112167.
Der volle Inhalt der QuelleFusions between chromosomes would compromise genome integrity. In particular, Non-Homologous End Joining (NHEJ) must be excluded from telomeres. Rap1p is the prominent telomere binding-factor in Saccharomyces cerevisiae and homologues are found in human cells and Schyzosaccharomyces pombe. Instead of binding directly the telomeric repeats, spRap1 and hRap1 are recruited by the major telomere binding-factor in these organisms, Taz1 and TRF2, respectively. It has been demonstrated that Taz1 and TRF2 protect chromosomes against end fusions by NHEJ. We took advantage in this study of a new conditional allele of RAP1, rap1-(∆), to test a role for Rap1p in telomere protection. In this allele, Rap1p is lost when cells progress toward stationary phase. This loss correlated with the appearance of end-to-end fusions detected by PCR. Telomere fusions were cloned. The fusion point seems difficult to sequence. However, the presence of a restriction site at the junction of some cloned fusions allowed us to determine that fusions occurred between telomeres of near wild-type length. Furthermore, we observed that the sequence at the fusion point seems random. Telomere fusions were not observed in rap1-(∆) cells defective for each factor required for NHEJ in budding yeast: Lig4p, Lif1p, Lif2p, Yku70p, Yku80p, Mre11p, Rad50p, and Xrs2p. The NHEJ-DNA polymerase Pol4p is also required. Sae2p and Tel1p, two known regulators of the Mre11p-Rad50p-Xrs2p complex not required for NHEJ, did not seem to be involved in telomere fusions. Thus, Rap1p protects telomeres from NHEJ. This newly described role is likely to be conserved
Chanut, Pauline. „Comprendre et perturber le choix de la voie de réparation des cassures double brin de l'ADN pour augmenter l'efficacité et la sélectivité des agents anticancéreux génotoxiques“. Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30151.
Der volle Inhalt der QuelleDNA double-strand break (DSB) is the most toxic DNA damage, because a single mis- or un-repaired DSB can lead to cell death. This toxicity is exploited in clinics to eradicate tumoral cells. So, among molecules currently used in chemotherapy, topoisomerase 1 (TOPO1) poisons such as camptothecin (CPT), are able to generate a particular type of DSB bearing one single end (seDSBs); these lesions are created when a replication fork collides with the TOPO1 blocked on the DNA. They are repaired by homologous recombination (HR) because, devoid of a second end, they cannot be ligated by non-homologous end-joining (NHEJ). The Ku heterodimer, the initiator of the NHEJ is both a major detector of the DSBs due to its nuclear abundance and strong affinity, and a powerful HR inhibitor. Therefore, the regulation of Ku binding to one-ended DSB is a crucial question for the understanding of mechanisms determining the choice of the suitable DSB repair pathway. In this context, my first thesis project aimed at deciphering the molecular mechanisms responsible for the DNA repair pathway choice at seDSBs. Firstly, using High Resolution Microscopy, I demonstrated that Ku and DNA-PKcs are rapidly recruited on seDSBs. Then, I showed that ATM-dependent phosphorylation of CtIP and the epistatic and coordinated actions of MRE11 and CtIP nuclease activities are required to limit the stable loading of Ku on seDSBs. I established that DNA-PKcs removal from seDSBs relies on ATM-dependent phosphorylation of the ABCDE cluster. Using a non-phosphorylable mutant of this cluster, I demonstrated that impaired DNA-PKcs removal prevents MRE11 from releasing Ku. However, my work also suggested the existence of an additional mechanism that contributes to prevent Ku accumulation at 50% of seDSBs. Finally, I demonstrated that Ku and DNA-PKcs persistence on seDSBs does not impair long range resection and RAD51 recruitment but compromises cell survival. My second thesis project was dedicated to target the DSB repair pathway choice mechanisms in order to potentiate the effect of CPT. Indeed, since ATM inhibition increases drastically the death of replicative cells treated with CPT, we may identify others sensitizers able to disrupt the repair pathway choice. On the basis of a cytotoxicity assay on mouse embryonic fibroblasts (MEFs), I performed a phenotypic screening of the NIH Clinical Collection and identified the antibiotic nitrofurantoin (NTF) and hydrocortisone acetate (HCA) as a sensitizer of MEFs to CPT. However, sensitization induced by NTF does not depend on Ku but rather seems to rely on Reactive Oxygen Species (ROS) generation by nitroreduction of the molecule and sensitization induced by HCA is not reproducible and is still under investigation. My work contributes to extend the knowledge of the repair pathway choice mechanisms involved in cell tolerance to CPT and opens new opportunities to potentiate its anticancerous property
Choudjaye, Jonathan. „Etude de l'organisation spatiale de la réparation des cassures double-brins de l'ADN“. Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30390.
Der volle Inhalt der QuelleDNA Double Strand Breaks (DSBs) form a major threat to the genome stability. To circumvent the deleterious effects of DSBs, cells activate the DNA damage response (DDR), which comprises events that lead to detection and repair of these lesions, as well as a delay in cell cycle progression. This DDR largely rely on two members of the PI3K-like kinase family : ataxia telangiectasia mutated (ATM) and DNA Protein Kinase (DNAPK), whose respective functions during the DDR remains controversial. Using a cell line, expressing the AsiSI restriction enzyme, combined with high resolution ChIP-chip mapping, sequence-specific DSB repair kinetics analysis and advanced high resolution microscopy, we uncovered that both ATM and DNA-PK are recruited to a confined region surrounding DSBs. However, once present at the DSB site, they exhibit non-overlapping functions on end-joining and yH2AX domain establishment. At the repair level, DNAPK is absolutely required for end-joining while ATM is dispensable although promoting repair fidelity. By contrast, ATM is the main kinase required for the establishment of the histone mark yH2AX at all breaks. We also clearly demonstrated that multiple AsiSI-induced DSBs are able to associate within "repair foci", in a manner that strictly depends on ATM, but not DNAPK, activity. Our study shed light on the respective roles of ATM and DNAPK regarding end joining and yH2AX domain establishment. Lastly it allowed us to uncover a function of ATM in the spatial organisation of the repair, more precisely in the clustering of multiple breaks within "repair foci" in order to be repaired
D'Augustin, de Bourguisson Ostiane. „Caractérisation de la dynamique de l'ADN-glycosylase OGG1 et de résidus responsables de son interaction avec l'ADN en cellules vivantes“. Electronic Thesis or Diss., Rennes 1, 2022. http://www.theses.fr/2022REN1B060.
Der volle Inhalt der QuelleDNA is constantly subjected to various stress, threatening its integrity, and consequently, the proper functioning of the cell. In order to preserve the genomic integrity, the cell can activate a large set of repair pathways. One of the most common genomic alteration is the base modification 8-oxoguanine (8-oxoG), an oxidized form of guanine. It is highly mutagenic, due to its tendency to pair with adenine instead of cytosine during replication. Thus, it needs to be detected and repaired on time to avoid G:C to T:A transversions. 8-oxoG paired with cytosine is recognized and excised by the 8-oxoguanine DNA-glycosylase (OGG1), which initiates the base excision repair pathway. Although OGG1 has been widely studied in vitro and many structural data are available, many questions remain concerning the dynamics of the protein within the cell nucleus. Hence, the goal of my PhD project was to characterize the dynamics of OGG1 searching for 8-oxoG and get new insights about the residues or functions of OGG1 that regulate these dynamics. I was able to show that the interaction between OGG1 and DNA is crucial for the efficient search of 8-oxoG, and that mutating the residues involved in such interaction impairs OGG1 dynamics and its ability to detect and excise 8-oxoG. Similarly, 8-oxoG detection, but also that of the facing cytosine, both play an important role in the function of the DNA-glycosylase and in its ability to accumulate at the sites of damage. Finally, the NNN motif, which is highly conserved but very poorly characterized, seems to be essential to the specific association with 8-oxoG, but not for the nuclear exploration by OGG1
Buck, Dietke. „Analyse moléculaire de patients présentant un déficit immunitaire combiné avec microcéphalie associé à un défaut général de la réparation de l'ADN“. Paris 5, 2005. http://www.theses.fr/2005PA05N34S.
Der volle Inhalt der QuelleMolecular analysis of patients presenting combined immunodeficiency and microcephaly associated with a general DNA repair defect DNA double strand breaks (DNA dsb) formed during V(D)J recombination are modified and ligated by general DNA repair factors of the non homologous end joining pathway (NHEJ), which comprises six known proteins : Ku70/Ku86/DNAPKcs, Artemis and Xrcc4/Lig4. First, we have shown that hypomorphic mutations of Lig4 are able to cause severe combined immunodeficiency associated to radiosensitivity (RS-SCID) in humans, characterized by a V(D)J recombination defect in vitro, which is complemented by the wild-type form of Lig4. Second, we have identified a new V(D)J/NHEJ factor by functional and genetic analysis of a group of patients presenting a phenotype similar to Lig4 deficient patients. The gene encoding this new factor, which we have called Cernunnos, is mutated in all analysed patients. The NHEJ deficiency observed in the patients' cells is complemented by the wild-type form of Cernunnos
Giraudon, Christophe. „Effets de nouveaux composés anticancéreux sur la réparation et la transcription sur l'ADN“. Strasbourg, 2011. http://www.theses.fr/2011STRA6073.
Der volle Inhalt der QuelleThe DNA, encoder of our genetic information, is constantly attacked by diverse agents. In order to maintain its genome integrity, the cell possesses several repair mechanisms. The latter allow the repair of the DNA damages and prevent mutagenesis. However, a high DNA lesion load or a DNA repair mechanism deficiency may trigger the generation of mutations during replication and transcription thereby putatively contributing to tumorigenesis. During my PhD, I was interested in the mechanism of action of two novel anticancer compounds. Trabectedin, a molecule isolated from the sea-origin tunicate Ecteinascidia turbinata and Zalypsis, a compound structurally related to jorumycin, exhibit anticancer properties against a large variety of tumors. We demonstrated that these compounds behave as interstrand crosslinking agents although they covalently bind to only one DNA strand. These molecules induce a bend in the DNA, which is recognized and cleaved by a cellular endonuclease, XPF/ERCC1. They also display an effect on DNA transcription. Indeed, Trabectedin and Zalypsis inhibit gene expression by preventing the recruitment of transcription factor Sp1 and/or by blocking RNA pol II progression regardless of the strand they are located on. My PhD thesis gives insights into the mechanisms of action of two promising anticancer compounds namely Trabectedin and Zalypsis and may guide future cancer treatment researches
Meister, Peter. „Usines de réplication et de réparation de l'ADN chez la levure Schizosaccharomyces pombe“. Paris 11, 2004. http://www.theses.fr/2004PA112124.
Der volle Inhalt der QuelleWhen double-strand breaks are detected on DNA, signaling and repair processes are activated. Activation can be visualized in vivo following the formation of sub-nuclear structures composed of DNA ends, repair and signaling factors. In the model organism Schizosaccharomyces pombe, we revealed these structures in vivo, using fluorescence microscopy and fluorescent fusion proteins. In a first study, we show that signaling factors colocalise with repair factors after induction of DSBs by gamma irradiation. Moreover, these "foci" or "factories" colocalise partially with PCNA, a ubiquitous DNA repair and replication factor. Taking advantage of fission yeast easy genetic analysis, we also studied the genetic determinant of factories formation. In a second study, we were interested by the relationship between replication and recombination after-replication forks blockage by depletion of the desoxyribonucleotides pool. The study is based on strains allowing simultaneous visualization of a replication and a recombination factor. We show that in the presence of replication fork blocks, lack of intra-S phase checkpoint induces appearance of recombination foci. Moreover, in wild-type cells, the intra-S checkpoint delays recombination till replication is almost complete following replication forks blockage. Finally, recombination induced by the absence of intra-S checkpoint in the absence of nucleotides seems to be at least partially responsible for replication fork collapse. In the third study presented here, we describe the spatial and temporal organization of DNA replication in S. Pombe. During S-phase, PCNA forms sub-nuclear foci. We show for the first time in vivo in a unicellular organism that these foci are replication factories (clusters of replication forks). These replication factories display reproducible temporal and spatial organization. Finally, we analyze the dynamics of these factories, as well as the effects of deleting components of the intra-S checkpoint on the organization of DNA replication
Bellacosa, Alfonso. „Le locus MED1 dans la réparation de l'ADN et lors du développement embryonnaire“. Paris 11, 2004. http://www.theses.fr/2004PA112247.
Der volle Inhalt der QuelleThe base excision repair enzyme MED1 (also known as MBD4), identified as an interactor of the mismatch repair (MMR) protein MLH1, acts as a thymine and uracil DNA N-glycosylase specific for G:T and G:U mismatches at CpG sites. Methylating agents are a class of antitumor drugs that cause cytotoxicity by inducing O6-methyguanine (O6-meG). O6-meG can direct misincorporation of thymine during replication, generating O6-meG:T mismatches. MED1 was found to exhibit thymine glycosylase activity on O6-meG:T mismatches. We generated mice with targeted inactivation of the Med1 gene and prepared mouse embryonic fibroblasts (MEFs) with different Med1 genotype. Unlike wild type and heterozygous cultures, Med1-/- MEFs failed to undergo G2-M cell cycle arrest and apoptosis upon treatment with the methylating agent Nmethyl-N'-nitro-N-nitrosoguanidine (MNNG). Resistance of Med1-/- MEFs to MNNG was due to a tolerance mechanism, because DNA damage accumulated but did not elicit checkpoint activation. Interestingly, steady state amounts of several MMR proteins are reduced in Med1-/MEFs, in comparison to Med1+/+ and Med1+/+ MEFs. Thus, MED1 has an additional role in DNA damage response to anti-tumor agents and is associated with integrity of the MMR system. Embryonic lethality in mice was caused by homozygosity for the targeted Med1 allele lacking exons 1 to 3, but not for the allele lacking exons 2 to 5. This discrepancy maybe explained by concurrent inactivation of neighboring gene Wdr10. Wdr10 shares a portion of exon 1 with Med1 in the opposite orientation. This suggests that the two genes may represent a functional unit necessary for normal development
Roa, Hélène. „Etude des voies de signalisation de la réparation de l'ADN chez Arabidopsis thaliana“. Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13052.
Der volle Inhalt der QuellePlants are continuously exposed to DNA damage. According to the kind of damage, plants have to activate specific signaling pathways that are well conserved through the evolution. Our work first allowed us to reveal an AtRNR specific one marker of DSB repair pathway which expression is ATM and AtE2Fa dependant, the AtRNR2-3 bis gene. A replicative stress marker gene was also identified, the AtTSO3 gene, coding for a TCX protein expressed in the nuclear. A model of transcriptional regulation mediated by ATR in response to replicative stress was established with the AtRNR2-3 and AtRNR2-5 genes. The expression of the last example is dependant on the RAD9 and RAD17 proteins. Concurrently, to visualize in planta the expression of GUS reporter gene conducted by candidate gene promoters, in DNA damage response, we have developed a new non-invasive approach by MRI (Magnetic Resonance Imaging) in Arabidopsis thaliana. These different approaches will allow us to better understand the DNA repair signaling in plants trough the development
Bourdat, Anne-Gaëlle. „Lésions tandem radio-induites de l'ADN : formation, insertion dans des oligonucléotides et réparation“. Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10100.
Der volle Inhalt der QuelleFrance, Benoît. „Étude du rôle des facteurs MYSM1 et ZNF699 dans la réparation de l'ADN“. Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCB072.
Der volle Inhalt der QuelleFor the last 20 years, important knowledge were acquired regarding the implication of the DNA damage response (DDR) in the development, maturation and function of the immune system. The lab DGSI has shown that DNA repair deficiencies can lead to immune disorders and in some cases to cancer predisposition. The first part of this thesis is based on the study of a patient exhibiting an immune deficiency and developmental problems. An homozygous misense mutation affecting the catalytic site of the protein MYSM1 was identified for this patient. MYSM1 is a metalloprotease, targeting monoubiquitinated histone H2A on lysine 119 (H2AK119ub), a marker of transcription silencing. Based on murine models, MYSM1 was described as a transcriptional derepresser of genes implicated in hematopoietic stem cells homeostasis and lymphocytes differentiation. The MYSM1 deficient patient suffered from a complete absence of B cells, a T cell lymhopenia, some hematopoietic defects and developmental abnormalities. As observed in the murine model, those symptoms could be explained by a transcriptional deregulation of factors implicated in the immuno-hematopoietic development. However, patient's fibroblasts are hypersensitive to certain genotoxic compounds. Hence, the DDR seems to be impaired in the patient cells, which is not described in murine models, and suggests an implication of MYSM1 in the DDR. A second part of the thesis focuses on ZNF699, wich is a zinc finger protein. An homozygous insertion of one nucleotide, leading to a frameshift, was identified in the gene coding for ZNF699 in a patient suffering from medullar aplasia, accelerated aging and short telomeres. Cells from this patient are also hypersensitive to some gentoxic compounds, suggesting the implication of ZNF699 in the DDR. The aim of this work is to understand the role of these two factors MYSM1 and ZNF699 in each patient pathology, and decipher their respective implication in the DDR
Lemadre, Elodie. „Nouveaux rôles anti-tumoraux de STAT1 : expression des immunoglobulines et réparation de l'ADN“. Thesis, Paris 13, 2014. http://www.theses.fr/2014PA132020/document.
Der volle Inhalt der QuelleThe transcription factor STAT1, as a major effector of interferon, plays a key role in innate immunity. Through its strong anti-proliferative and pro-apoptotic properties STAT1 is also considered as a tumor suppressor. The aim of this project was to delineate new potential tumor suppressor properties for STAT1 in two signaling mechanisms: i) Ig expression in plasmacytoid cells and ii) cellular response to genotoxic stress.Our kinetic experiments, upon “de novo” expression of STAT1 in a rare STAT1-deficient cell line showed its modulation of membrane IgG expression. The underlying mechanism involves a STAT1-dependent inactivation of STAT3 and subsequently a decreased expression of BLIMP1, a major contributor to plasma cell differentiation. Since STAT1, like STAT3, is able to bind to the BLIMP1 promoter elements a transcriptional interference cannot be excluded.During alkylating agent treatment with MNNG we have observed the presence of STAT1 in DNA repair complex. STAT1 expression allows the recruitment into a MLH1/p53 complex of the kinase c-Abl. This complex leads to cytotoxic dependence on c-Abl kinase activity, an efficient DNA repair with a transient cell cycle arrest and to signaling mechanisms toward cell survival. At longer term of exposure STAT1 also lead to cellular resistance to treatment.These results provide evidences for new anti-tumor roles of STAT1 in two major regulatory systems and indicate STAT1 as a potential therapeutic target
Berthelot, Vivien. „Biochimie analytique de complexes de réparation de l'ADN : élaboration d'un système analytique intégré“. Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112386/document.
Der volle Inhalt der QuelleIn eucaryotic cells, DNA double-strand breaks are repaired through two main pathways : the homologous recombination and the non homologous end joining . Altough these pathways are well characterized, two particular aspects of the repair remain poorly understood :- If two separated pathways may occur in the cells, which mechanism(s) govern the choice of the pathway that will ultimately lead to the repair ?- If the double-strand break is induced by ionizing radiations – as those employed in anti-cancerous radiotherapy – how does the repair occur if the DNA ends at the edge of the break are not compatible with a direct ligation ? A proper knowledge of the proteins involved in this repair would allow the development of additives, useful to increase the efficiency of the radiotherapy.To investigate these questions, we designed a new analytical system allowing : 1) the specific recruitment of DNA double-strand break repair complexes on home-made chromatographic phases, 2) the separation of these complexes in a non-denaturing polyacrylamide gel and their subsequent visualization and 3) their biochemical characterization.The methodology developped in this work has been focused on the following points : 1) we designed and implemented a chromatographic system allowing the distinction between proteins recruited onto duplex DNA oligonucleotide with free DNA ends (mimicking DNA double-strand breaks) and proteins fixed onto the internal sequence of the same oligonucleotides ; 2) we adapted to our problematic a methodology of non-denaturing electrophoresis thus allowing the separation of the purified complexes while guaranteeing their integrity during the migration, 3) we also determined their composition by mass spectrometry after their visualization.The biochemical study has shown that the purified complexes were still functionnal, that is they were able to efficiently ligate two oligonucleotides. The study of the data provided by the mass spectrometry analysis of independant experiences proved that the complexes belonged to the DNA physiology and were especially representative of the diversity of the DNA repair pathways.Interestingly, we observed that some of the protein specifically recruited onto the the double-strand breaks were not known to be involved in the DNA repair (nucleotide synthesis, checkpoint, DNA topology, cytoskeleton).The rôle of these proteins should be characterized in cellulo especially with siRNA. On the other hand we will also use the methodological development described above to study the repair mechanisms of radio-induced DNA double-strand breaks occuring in the irradiated tumorous cells. To achieve this study we will elaborate new chromatographic phases with pre-irradiated oligonucleotides
Warcoin, Mathilde. „Etudes de pathologies humaines atypiques associées à des défauts de réparation de l'ADN“. Paris 7, 2009. http://www.theses.fr/2009PA077123.
Der volle Inhalt der QuelleInherited mutations in genes involved in DNA repair result in two différent pathologies. First, some mutations lead to severe pediatric diseases called "chromosomes breakage syndromes" such as ataxia-telangiectasia, the Nijmegen breakage syndrome and the ataxia-telangiectasia like disorder due to inactivation of the ATM, NBN/NBS1 and MRE11 gene respectively. These syndromes share some symptoms, including chromosomal instability, immune defect, radiosensitivity and a predisposition to cancer. Second, other alterations of some genes of the DlsfA damage repair pathway are responsible for an inherited predisposition to breast cancer. We screened adult and pediatric patients presenting some clinical features of those chromosomes breakage syndromes. In a family of two adult siblings, whose call sign was a hypofertility and an evocative cytogenetic we detected germline biallelic nonsense-mutations of the NBN gene. Hypersensitivity to ionizing radiation similar to that observed in the Nijmegen syndrome was found in these two patients. In a second family, the first case of a mono-allelic deletion of the RAD50 gene was identified in a young woman with isolated mild ataxia. Both genes encode proteins belonging to the MRN complex (MRE11/RAD50/NBN). This complex plays a role in the early response to DNA damage. These original observations demonstrate the existence of a new class of patients mutated in genes involved in the response to DNA damage. These adult subjects without developmental abnormalities, have hypomorphic variants of these genes that result in major defect of the DNA repair. In the context of infertility, cancer predisposition and unexplained hypersensitivity to radio / chemotherapy, abnormalities of these genes must be investigated
Dernoncourt, Emma. „SAF-A - hnRNP U : une protéine à l'interface du métabolisme de l'ARN et des dommages à l'ADN“. Toulouse 3, 2013. http://www.theses.fr/2013TOU30246.
Der volle Inhalt der QuelleAn expanding aspect of the DNA Damage Response (DDR) is its connexion with RNA metabolism. My team has identified the RNA-binding protein SAF-A/hnRNP U as a substrate for DNA-PK, the key kinase in DNA double-strand breaks repair. I have investigated SAF-A involvement in the DDR. After laser microirradiation, SAF-A-GFP dynamics exhibited a two phases profile with a first transient recruitment in the damaged nuclear area followed by a prolonged exclusion. The two phases were uncoupled. SAF-A recruitment was PARP-dependent, while its exclusion relied on ATM, ATR and DNA-PK. SAF-A RNA-binding domain recapitulated SAF-A dynamics after DNA damage. Mass-spectrometry analysis using this domain as a bait identified mostly RNA-binding partners, at least two of them (FUS and TAF15) exhibited similar dynamics. Upon transcription inhibition, SAF-A exclusion was abolished, supporting that it concerns the pool of SAF-A engaged in RNA metabolism. Given that abnormal transcription conditions have been shown to promote RNA:DNA hybrids formation (R-loop), we constructed a cell line expressing a catalytically inactive mCherry-tagged RNAseHI (RmC), which retains its ability to bind R-loop. RmC recruitment to the laser damage site was abolished upon transcription inhibition. When SAF-A exclusion was blocked, RmC exhibited a prolonged recruitment, supporting that SAF-A release is a readout of R-loops resolution post-DNA damage. Finally, overexpressing this mutated RNAseHI negatively impacted cell survival after X-ray irradiation. These results uncover an anti-R-loop mechanism at DNA damage sites in transcribed areas testified by the post-damage exclusion of RNA-binding proteins from these sites
Aymard, François. „Rôle de la chromatine dans le choix de la voie de réparation des cassures double-brins à l'ADN“. Toulouse 3, 2014. http://thesesups.ups-tlse.fr/3749/.
Der volle Inhalt der QuelleAmongst all DNA damages, Double-Strand Breaks (DSBs) are the most harmful lesions, since they can lead to mutations or genome rearrangements associated with cancerogenesis. DSBs can be repaired by two main mechanisms: NHEJ (Non Homologous End Joining) and HR (Homologous Recombination). The mechanism by which one or the other pathway is favored to repair DSB is not entirely understood. In the nucleus, DNA is wrapped around histones and forms the Chromatin, a dynamique structure that is known to influence all processes involving DNA including DSB repair. Firstly, we showed that the chromatin landscape participate in the repair pathway choice. The transcriptionnally active chromatin is preferentially repaired by HR which is recruted on transcribed loci via the H3K36me3 histone mark. This study demonstrates an essential rôle of the chromatin in the DSB repair pathway choice, in human cells. Secondly, we mapped by ChIP-Seq numerous histone post-translationnal modifications suspected to be involved in DNA repair, before and after DSB induction. This study allowed us to study the induction, the distribution and the association with the different repair pathways of nine histone modifications These studies led to a better understanding of reciprocical influences between chromatin and repair, and especially the rôle of transcritpion and the repair pathway choice