WorldCat Identities

Beaujean, Nathalie

Overview
Works: 14 works in 30 publications in 2 languages and 210 library holdings
Genres: Laboratory manuals 
Roles: Editor, Other, Author, Opponent, Contributor
Classifications: QH442.2, 570
Publication Timeline
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Most widely held works by Nathalie Beaujean
Nuclear reprogramming : methods and protocols by Nathalie Beaujean( )

13 editions published between 2014 and 2016 in English and held by 182 WorldCat member libraries worldwide

Nuclear Reprogramming: Methods and Protocols, Second Edition includes not only classic methods to perform nuclear transfer in different species but also several techniques to assess the early and late development of the reconstructed embryos, at the cellular, molecular, and epigenetic level. Over the past several years, many technical improvements have been made to improve somatic cell nuclear transfer (SCNT) efficiency, all of which are reflected in the detailed chapters of this fully revised collection. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and up-to-date, Nuclear Reprogramming: Methods and Protocols, Second Edition will be of interest not only to cloners but also to researchers concerned with studying the development of embryos
Relationship between genome and epigenome : challenges and requirements for future research by Genevieve Almouzni( )

4 editions published in 2014 in English and held by 7 WorldCat member libraries worldwide

Understanding the links between genetic, epigenetic and non-genetic factors throughout the lifespan and across generations and their role in disease susceptibility and disease progression offer entirely new avenues and solutions to major problems in our society. To overcome the numerous challenges, we have come up with nine major conclusions to set the vision for future policies and research agendas at the European level
STRUCTURE DE LA CHROMATINE ET ACTIVITE TRANSCRIPTIONNELLE DANS LES EMBRYONS DE SOURIS NORMAUX OU APRES TRANSFERTS DE NOYAUX : ROLE DE LA PROTEINE HMG-I by Nathalie Beaujean( Book )

2 editions published in 2001 in French and held by 4 WorldCat member libraries worldwide

DANS L'EMBRYON DE SOURIS, LA TRANSCRIPTION ZYGOTIQUE NE DEMARRE PAS IMMEDIATEMENT APRES LA FECONDATION, L'ACTIVITE TRANSCRIPTIONNELLE NE REPRENANT QU'A LA FIN DU STADE UNE-CELLULE. LES FACTEURS MOLECULAIRES RESPONSABLES DE CETTE REACTIVATION RESTENT A IDENTIFIER, MAIS IL EST GENERALEMENT ADMIS QUE LA STRUCTURE DE LA CHROMATINE SERAIT UN ELEMENT REGULATEUR CLE. LES RESULTATS OBTENUS AU COURS DE CE TRAVAIL DE THESE MONTRENT QUE LA PROTEINE HMG-I (PROTEINE CHROMATINIENNE NON-HISTONE) EST IMPLIQUEE DANS LA REMISE EN ROUTE DE LA TRANSCRIPTION ZYGOTIQUE. CETTE PROTEINE LIE SELECTIVEMENT LES SEQUENCES RICHES EN PAIRES DE BASES DA DT PAR L'INTERMEDIAIRE D'UN DOMAINE DE LIAISON APPELE AT-HOOK. BIEN QUE PRESENTE DANS LES OVOCYTES, LA PROTEINE EST ABSENTE DES PRONOYAUX D'EMBRYONS UNICELLULAIRES JUSTE APRES LEUR FORMATION ET SUIT UNE CINETIQUE DE LOCALISATION NUCLEAIRE PARTICULIERE QUI SEMBLE PARTICIPER A LA REGULATION TEMPORELLE DE LA TRANSCRIPTION ZYGOTIQUE. PAR AILLEURS, LA MICROINJECTION D'HMG-I DANS DES EMBRYONS UNICELLULAIRES, AINSI QUE LA MICROINJECTION D'UN PEPTIDE CORRESPONDANT AUX MOTIFS AT-HOOK, AVANCE LE DEMARRAGE DE LA TRANSCRIPTION DE DEUX HEURES. CET EFFET ACTIVATEUR REQUIERT LA FIXATION DE LA PROTEINE A L'ADN ET IMPLIQUE UNE MODIFICATION DE LA STRUCTURE CHROMATINIENNE, PROBABLEMENT PAR COMPETITION AVEC L'HISTONE H1. CEPENDANT, AUCUNE INDICATION NE PERMET DE DIRE SI CET EFFET EST DIRECT OU S'IL IMPLIQUE LE RECRUTEMENT D'AUTRES ELEMENTS. J'AI MONTRE QUE LE DEGRE D'ACETYLATION DE L'HISTONE H4, QUI REPRESENTE UN AUTRE ELEMENT REGULATEUR DE LA STRUCTURE CHROMATINIENNE ET DE LA TRANSCRIPTION AU DEBUT DU DEVELOPPEMENT EMBRYONNAIRE, SEMBLE CONNECTE A LA PROTEINE HMG-I. L'ETUDE D'UN AUTRE MODELE, CELUI DU TRANSFERT DE NOYAUX DE CELLULES SOMATIQUES DANS DES OVOCYTES ACTIVES, SUGGERE QU'HMG-I JOUE AUSSI PROBABLEMENT UN ROLE DANS LES REMANIEMENTS DE LA STRUCTURE DE LA CHROMATINE ET LES CHANGEMENTS D'ACTIVITE TRANSCRIPTIONNELLE QUI ACCOMPAGNENT CES TRANSFERTS
Recherche et développement de biomolécules permettant l'amélioration des biotechnologies de la reproduction chez le bovin. by Guillaume Martinez( )

1 edition published in 2016 in French and held by 2 WorldCat member libraries worldwide

The reproductive biotechnologies are now widely used in control of animal and human fertility. However, these technics have low yields and are currently the subject of much research. In this context, the present thesis focuses on the search for new pro-fertility molecules in cattle, organized around two axis : the first one is to test the pro-fertility properties of an enzyme from lipid metabolism on maturation, fertilization and preimplantation embryo development in vitro, and the second one is to discover molecules to improve sperm fertilizing ability. Here, we show that application of the enzyme significantly improve the number and quality of embryos at the blastocyst stage. Expertise in the use of this enzyme (time of treatment, concentration, etc.) was developed. This thesis also allowed the characterization of different compounds with different properties. Among them, one original molecule increase sperm velocity. This compound is promising because it works on sperm from the testis, epididymis or ejaculate before or after freezing
Trichostatin A treatment of cloned mouse embryos improves constitutive heterochromatin remodeling as well as developmental potential to term by Walid E Maalouf( )

1 edition published in 2009 in English and held by 2 WorldCat member libraries worldwide

Contrasting epigenetic states of heterochromatin in the different types of mouse pluripotent stem cells by Matteo Tosolini( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

L'organisation post-méiotique de l'épigénome mâle by Sophie Barral( )

1 edition published in 2018 in French and held by 2 WorldCat member libraries worldwide

Spermatogenesis, the process of producing male gametes, represents a relevant physiological model for the study of chromatin dynamics. Indeed, a drastic reorganization of the genome is observed at the end of spermatogenesis, during post-meiotic stages of the development of the male germ cells. These reorganizations are intended both to compact the genome to protect it before and during fertilization and to establish a specific male epigenome necessary for early embryonic development. In spermatozoa, during these post-meiotic stages, chromatin is completely reorganized so that the protamines replace the histones. This reorganization is initiated by a wave of genome-wide histone acetylation, followed by massive replacement of histones by small basic proteins, transition proteins and protamines. The molecular mechanisms responsible for this reorganization of the genome remain very poorly known today. My thesis aims to explore these mechanisms by using gene inactivation in mouse of epigenetic actors specifically expressed in post-meiotic germ cells : the nuclear factor Nut (Nuclear protein in Testis) and the histone H2A variant, H2A.L.2. We have demonstrated that the Nut protein interacts and stimulates the p300 acetyltransferase activity and induces the hyperacetylation of histone H4 precisely on the lysine residues at 5 and 8 positions. This acetylation is necessary for the interaction with the first bromodomain of Brdt initiating the process of histone replacement by protamines. Thus, the Nut factor is the main element of the histone acetylation wave. We have also deciphered the crucial role of H2A.L.2 in the “opening ” of nucleosomal structures in post-meiotic germ cells thus allowing its invasion by the transition proteins. These transition proteins will in turn generate a platform for the recruitment and maturation of protamines and induce the formation of transient structures before the final compaction of the mature sperm genome. These studies allowed us to establish for the first time a coherent molecular model for understanding the post-meiotic epigenetic programming of the male genome and its impact on male fertility
Base moléculaire de la programmation post-méiotique du génome mâle by Naghmeh Hoghoughi( )

1 edition published in 2019 in English and held by 2 WorldCat member libraries worldwide

La chromatine des cellules spermatogèniques subit une réorganisation radicale pendant la spermiogenèse. Ce phénomène se produit pour deux raisons principales : premièrement, pour établir un génome très compact par l'incorporation de protamine, afin de protéger le génome du sperme avant et pendant la fécondation. Deuxièmement, afin de transférer avec succès l'information paternelle portée par le génome du sperme, à la génération suivante. Récemment, notre laboratoire a identifié différents acteurs et mécanismes moléculaires, qui sont au cœur de cette réorganisation radicale du génome. Une hyperacétylation des histones à l'échelle du génome amorce le processus de remplacement des histones par des protéines de transition et des protamines. Notre laboratoire a identifié NUT (Nuclear protein in Testis) comme le principal regulateur de l'hyperacétylation des histones au début du processus de transition histone-protamine. NUT par recrutement d'histone acétyltransférase CBP/p300, induit une hyperacétylation de l'histone H4 principalement au niveau des résidus lysine 5 et lysine 8. Ensuite, le premier bromodomaine de BRDT (bromodomaine contenant le facteur spécifique du test) reconnaît l'acétylation des histones et déclenche le processus d'élimination des histones. Le variant H2A.L.2 (H2A.Like 2) spécifique au testicule, forme un dimère avec le variant d'histone H2B, TH2B, au moment de l'éviction des histones dans les spermatides allongés. Le dimère H2A.L.2-TH2B s'incorpore alors dans la chromatine et ouvre la structure du nucléosome. Ceci permet l'invasion des histones par les protéines de transition ainsi que le traitement pré-protaminique. Les protamines déplacent finalement les complexes histone-TPs et compactele génome. Auparavant, notre laboratoire a rapporté qu'une fraction de H2A.L.2 resteassociée à des régions hétérochromatines péricentriques dans les spermatozoïdes matures. Au cours de mon doctorat, nous avons d'abord découvert les bases structurelles et moléculaires de l'activation du CBP/p300. Nous spéculons que les mêmes mécanismes pourraient mener à l'acétylation des histones induite par Nut-p300-dépendante, menant à l'initiation de l'élimination des histones dans les phases post-méiotiques de la spermatogenèse. Nous avons démontré également que la dissociation des nucléosomes à la suite de l'incorporation du H2A.L.2-TH2B permet au dimère H2A.L.2-TH2B de s'associer à l'ADN de façon stable, tandis que le tétramère H3-H4 est déplacé. Ceci conduit à la génération de structures à base de dimères H2A.L.2-TH2B, qui persistent dans le sperme mature. De plus, nous avons déchiffré la base moléculaire de la capacité intrinsèque de H2A.L.2 à cibler les régions hétérochromatines péricentriques. Nous avons également identifié un rôle critique vis-à-vis de l'ARN dans la régulation et le contrôle du renouvellement et de la localisation d' H2A.L.2 dans les régions hétérochromatines péricentriques. En conclusion, nos travaux mettent en évidence la présence de structures à base de dimères dans la chromatine du sperme, ainsi qu'une reprogrammation spécifique de l'hétérochromatine péricentrique masculine. Ceci pourrait porter des informations essentielles transmissibles à la génération suivante
Three-dimensional analysis of nuclear heterochromatin distribution during early development in the rabbit by Amélie Bonnet-Garnier( )

1 edition published in 2018 in English and held by 2 WorldCat member libraries worldwide

Identification and characterization of Polycomb repressed gene-enhancer loops by Charbel Souaid( )

1 edition published in 2019 in English and held by 1 WorldCat member library worldwide

In the mouse embryonic stem cells (mESCs), Polycomb Group Proteins (PcG) repress developmental genes and thereby participating in the maintenance of the pluripotency. PcG repress genes by depositing the H3K27me3 histone marks on their regulatory elements, followed by chromatin compaction. In addition to the H3K27me3 marks, those genes carry H3K4me3 active marks and were characterized as bivalent. Intriguingly, at many PcG repressed genes, DNA loops can be observed with enhancer elements, which are normally thought to have an activating function. The aim of my project is to both describe and mechanistically dissect the function of Polycomb repressed promoter - enhancer loops.During my PhD, I aimed firstly to identify all promoter-enhancer loops involved by PcG repressed genes in mESCs. I have performed ChIP-seq profiling of 4 histone marks and identified around 2500 PcG repressed promoters and 13000 enhancers. Using a recently published high-resolution Hi-C data in mESCs, I have identified all DNA loops that are formed by PcG repressed promoters. Surprisingly, a high percentage of bivalent promoters were found to contact active enhancers. The presence of those loops were validated by ultra-high 4C-seq on selected genes and imply a small significant increase of the gene expression without leading to a complete activation of the gene. I have established a more physiological ESC model (2i+VitC) where H3K27me3 is reduced at all promoters. I have performed ChIP-seq, where bivalent promoters were all classified as H3K27me3 negative. RNA-seq experiments have showed that those genes do not become activated. 4C-seq experiments have revealed that those loops do not disappear after PcG removal, whereas the half of interacted enhancer loose their H3K27ac active marks. Those genes seem to remain repressed by an unknown mechanism. These results argue for a possible role of PcG in preparing the gene for their activation by blocking the productivity of such DNA loops. Secondly, I aimed to functionally characterize those DNA loops by using a CRISPR/dCas9 approach to completely remove H3K27me3 from two PcG repressed genes that contact active enhancers Pax6 and Nkx1-1 genes. This system is still under optimization steps.My project revealed the most systematic characterization of DNA loops under the regulation of PcG, providing important insight how PcG function to inactivate such loops. I have highlighted an additional function of PcG which the involvement in the repression of already establish loops between active enhancers and promoters and thereby blocking the productivity of such activating loops. This function is an addition to the already described repressive function of PcG on both promoters and poised enhancers
Impact du stress oxydant sur l'intégrité de l'épigénome spermatique murin by Alexandre Champroux( )

1 edition published in 2018 in French and held by 1 WorldCat member library worldwide

In Mammals, the success of fertilization and embryonic development, are associated to the quality of the reproductive cells: male gametes (spermatozoa) and female gametes (oocytes); each bringing half of the genetic heritage of the future individual. This genetic heritage may be compromised by various processes a very common one being radical attacks in cases of oxidative stress, it could diminish the quality of gametes and therefore the success of reproduction. It is well described that sperm DNA oxidative damage (SDOD) is one of the causes of male infertility frequently associated with reproductive failures in the context of natural or artificial conception in humans. To better understand the impact of oxidative damage on the quality of sperm, our team generated mouse models with SDOD. Characterization of these transgenic mice has shown that SDOD alone was associated with increased embryo defects, miscarriages and perinatal mortality. The team also brought forward that SDOD concerns preferentially specific regions of the sperm nucleus. In addition, the team suggested that sperm chromosomes were not identically susceptible to oxidative damage.In this thesis work, I developed and implemented fluorescence in situ hybridization (FISH) protocols to study chromosome positioning in the mouse sperm. I confirmed that susceptibility of chromosomes to oxidation is determined by their position in the murine sperm nucleus. In parallel, I addressed the question whether the sperm epigenome (particularly DNA methylation) was modified in a situation of post-testicular oxidative stress. Preliminary results seem to show that SDOD disturbs the sperm epigenetic profile.In parallel, in a pre-clinical approach, I contributed to show that an oral antioxidant supplementation can correct SDOD by modifying the antioxidant response of the epididymal tissue of the treated animals
Study of the organisation and the transcriptional activity of mouse major satellites by Lorena Kolar-Znika( )

1 edition published in 2015 in English and held by 1 WorldCat member library worldwide

Dans les cellules de souris, l'hétérochromatine péricentromérique, caractérisée par les répétitions des satellites majeurs et une signature épigénétique spécifique, la triméthylation de l'histone H3 sur la lysine 9 (H3K9me3), est organisée en structures nucléaires particulières appelées chromocentres. Cette région est transcriptionnellement active, produisant des ARN non-codants. Pour caractériser le profil transcriptionnel des satellites majeurs, nous avons utilisé des oligonucléotides LNA séquence spécifiques, pour des expériences de northern blot. Nous avons mis en évidence un profil de transcription complexe, révélé avec les sondes conçues pour cibler les deux brins des répétitions des satellites majeurs. Ce profil est modulé en réponse au choc thermique, condition dans laquelle un court ARN transcrit par l'ARN polymérase III, est surexprimé. Cependant, des problèmes de spécificité inhérents à l'utilisation de ces sondes LNA, ne nous ont pas permis de confirmer que les transcrits détectés ont pour origine les satellites majeurs. La seconde partie de ce travail a consisté en l'étude de l'impact de la modification ciblée de H3K9me3 aux satellites majeurs par une protéine TALE fusionnée à l'histone déméthylase mJMJD2D. Nous avons montré que le signal H3K9me3 est aboli dans les cellules transfectées avec cette protéine TALE. La déméthylation provoque des changements morphologiques des chromocentres, tels que l'augmentation de la taille des foci de satellites majeurs, accompagnés par la diminution de leur nombre, suggérant la fusion de plusieurs chromocentres
Evolution of the human & mouse X-chromosome inactivation regulatory network by Olga Rosspopoff( )

1 edition published in 2018 in English and held by 1 WorldCat member library worldwide

Long non-coding RNAs (lncRNAs) have emerged as the major output of mammalian transcriptomes. As of today, the function of the majority of lncRNAs remains largely enigmatic and importantly may be mediated by various entities such as the transcript itself, the act of transcription or key regulatory elements within the locus. A remarkable characteristic of lncRNAs is their poor evolutionary conservation, which raises the question of their contribution to species-specific regulatory mechanisms.X chromosome inactivation (XCI) is a paradigm for epigenetic processes mediated by lncRNA genes (LRGs) and a powerful model to explore their functional, mechanistic and evolutionary aspects. XCI is a process initiated early during embryonic development, which ensures the dosage compensation of X-linked genes between male and female in mammals. In the mouse, XCI is triggered by the combined action of several LRGs, among which Xist is the key regulator of the process. Xist is produced from a genomic region, the X-chromosome inactivation center (Xic), that is enriched for LRGs described either as positive or negative XCI regulators. In the present study, we investigated the evolutionary conservation of two candidate LRGs, JPX and FTX, and their contribution to XIST regulation in both human and mouse.In the mouse, we demonstrated that the Jpx RNA is required for proper Xist expression and acts as a post-transcriptional regulator of Xist, most likely by affecting its accumulation or stability. In striking contrast, in human, it is JPX transcription, but not the transcript itself, that controls the RNA Polymerase II (RNAPII) recruitment at XIST promoter. Accordingly, the two genes are interacting through local chromosome conformation, emphasized by RNAPII bridges in between the two loci. While the function of JPX/Jpx in promoting XIST/Xist accumulation is conserved between human and mouse, the underlying mechanisms diverge markedly. On the other hand, preliminary results on FTX function in human, suggest that it might be involved in XCI maintenance in human in very specific cellular contexts. Altogether, these results shed a new light on the functional evolution of XIST regulatory network between mouse and human that might be specifically adapted to XCI requirements in each species. This work highlights the functional plasticity of lncRNAs in evolution and how it might play important roles in species-specific mechanism of gene regulation
Cellules souches pluripotentes induites de lapin : caractérisation moléculaire et fonctionnelle des états naïf et amorcé by Yann Tapponnier( )

1 edition published in 2015 in French and held by 1 WorldCat member library worldwide

Deux états d'autorenouvellement des cellules souches pluripotentes (PSCs) ont été définis, à savoir les états naïf et amorcé. De nombreuses différences existent entre ces deux états dont la plus marquante est la capacité unique des PSCs à l'état naïf, de coloniser l'embryon préimplantatoire et former des chimères. L'objectif de mon projet doctoral a été d'étudier la pluripotence chez le lapin. Dans ce cadre, j'ai d'abord entrepris de fabriquer et de caractériser des cellules souches pluripotentes induites (RbiPSCs), puis d'évaluer leur capacité à coloniser l'embryon et à former des chimères. Trois lignées de RbiPSCs dépendantes du FGF2 ont été obtenues par reprogrammation de fibroblastes de lapin. Leur caractérisation moléculaire et fonctionnelle a révélé des caractéristiques mixtes, naïves et amorcées. En revanche, sur le plan fonctionnel, elles sont incapables de coloniser l'embryon de lapin, une caractéristique de la pluripotence amorcée. La seconde partie de mon projet doctoral a consisté à reprogrammer des RbiPSCs vers l'état naïf. Dans ce but, j'ai surexprimé KLF2 et KLF4, deux gènes appartenant au réseau de pluripotence naïf, et utilisé les conditions de culture des PSCs de souris. Les cellules ainsi obtenues présentent un profil d'expression génique plus proche de celui de l'ICM de lapin, dû notamment à la réactivation de marqueurs spécifiques de la pluripotence naïve. Enfin, les cellules ainsi reprogrammées présentent une capacité accrue pour la colonisation de l'embryon préimplantatoire de lapin. Mes travaux constituent le premier exemple de reprogrammation de cellules souches pluripotentes vers l'état naïf chez le lapin. Les cellules ainsi produites ouvrent la voie à la fabrication de chimères somatiques et germinales
 
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Nuclear reprogramming : methods and protocols
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Nathalie Beaujean researcher

Nathalie Beaujean wetenschapper

Languages
English (24)

French (6)