A5053305582- DNA Repair Mechanisms
- Genomics and Chromatin Dynamics
- DNA and Nucleic Acid Chemistry
- Epigenetics and DNA Methylation
- Origins and Evolution of Life
- RNA and protein synthesis mechanisms
- Bacterial Genetics and Biotechnology
- Microtubule and mitosis dynamics
- Bacteriophages and microbial interactions
- Ubiquitin and proteasome pathways
- Plant Genetic and Mutation Studies
- Surfactants and Colloidal Systems
- RNA Research and Splicing
- Chromosomal and Genetic Variations
- Plant and Biological Electrophysiology Studies
- Diffusion and Search Dynamics
- Surface Roughness and Optical Measurements
- Plant Molecular Biology Research
- Electrostatics and Colloid Interactions
- Chromatin Remodeling and Cancer
- Force Microscopy Techniques and Applications
- Lipid Membrane Structure and Behavior
- Mesoporous Materials and Catalysis
- Polymer Surface Interaction Studies
- Philosophy and History of Science
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2014-2025
Centre National de la Recherche Scientifique
2009-2025
Université Paris-Saclay
2020-2025
Institut de Biologie Intégrative de la Cellule
2015-2025
CEA Paris-Saclay
2003-2025
Institut de Biologie et Technologies
2011-2021
Laboratoire de Physique de l'ENS de Lyon
2021
Génétique Animale et Biologie Intégrative
2019
Centre de Génétique Moléculaire
2016
Institut de Biologie de l'École Normale Supérieure
2011
Genome-wide replication timing studies have suggested that mammalian chromosomes consist of megabase-scale domains coordinated origin firing separated by large originless transition regions. Here, we report a quantitative genome-wide analysis DNA kinetics in several human cell types contradicts this view. combing HeLa cells sorted into four temporal compartments S phase shows origins are spaced at 40 kb intervals and fire as small clusters whose synchrony increases during fork velocity (mean...
The structure and biological function of the DNA double helix are based on interactions recognizing sequence complementarity between two single strands DNA. A strand can also recognize by binding in its groove forming a triplex. We now find that recognition occurs intact duplexes without any single-stranded elements as well. have imaged mixture fluorescently tagged, helical molecules identical nucleotide composition length (50% GC; 294 base pairs) but different sequences. In electrolytic...
In higher eukaryotes, replication program specification in different cell types remains to be fully understood. We show for seven human lines that about half of the genome is divided domains display a characteristic U-shaped timing profile with early initiation zones at borders and late centers. Significant overlap observed between U-domains also germline exhibiting N-shaped nucleotide compositional skew. From demonstration average fork polarity directly reflected by both skew derivative...
Abstract Large vertebrate genomes duplicate by activating tens of thousands DNA replication origins, irregularly spaced along the genome. The spatial and temporal regulation process is not yet fully understood. To investigate dynamics, we developed a methodology called RepliCorr, which uses correlation between patterns observed on stretched single-molecule obtained either combing or high-throughput optical mapping. analysis revealed two independent spatiotemporal processes that regulate...
Eukaryotic cells seem unable to monitor replication completion during normal S phase, yet must ensure a reliable time. This is an acute problem in early Xenopus embryos since DNA origins are located and activated stochastically, leading the random problem. combing, kinetic modelling other studies using egg extracts have suggested that potential much more abundant than actual initiation events time-dependent rate of initiation, I(t), markedly increases through phase rapid unreplicated gaps...
Although replication proteins are conserved among eukaryotes, the sequence requirements for initiation differ between species. In all species, however, origins fire asynchronously throughout S phase. The temporal program of origin firing is reproducible in cell populations but largely probabilistic at single-cell level. mechanisms and significance this unclear. Replication timing has been correlated with gene activity metazoans not yeast. One potential role a regulation to minimize...
Molecular combing of DNA is an extremely powerful fiber–stretching technique that often used in replication and genome stability studies. Optimal results mainly depend on the quality silanized surfaces onto which fibers are stretched. Here we describe improved method liquid-phase silanization using trimethoxy-octenylsilane/n-heptane as novel silane/solvent combination. Our simple produces homogenously modified coverslips a reproducible manner, but does not require any sophisticated or...
Chromatin organization is crucial for transcriptional regulation in eukaryotes. Mediator an essential and conserved co-activator thought to act concert with chromatin regulators. However, it remains largely unknown how their functions are coordinated. Here, we provide evidence the yeast Saccharomyces cerevisiae that establishes physical contact RSC (Remodels Structure of Chromatin), a remodeling complex nucleosome-depleted region (NDR) formation. We determine role Mediator-RSC interaction...
In human and other metazoans, the determinants of replication origin location strength are still elusive. Origins licensed in G1 phase fired S cell cycle, respectively. It is debated which these two temporally separate steps determines efficiency. Experiments can independently profile mean timing (MRT) fork directionality (RFD) genome-wide. Such profiles contain information on multiple origins' properties speed. Due to possible inactivation by passive replication, however, observed intrinsic...
The phase behavior of a supported dimyristoylphosphatidylcholine (DMPC) bilayer system has been investigated using neutron reflectivity. is fabricated by combination Langmuir−Blodgett, Langmuir−Schaeffer, and self-assembly techniques, while robustly associated with the substrate, remains separated from it substantial layer water, due to Helfrich type entropic repulsion. reflectivity data have analyzed quasi-molecular model, similar that used Wiener White (Wiener et al. Biophys. J. 1992, 61,...
The aggregation of short (294-base-pair) linear double-stranded DNA molecules into cholesteric spherulitic droplets in a brine solution polyethylene glycol has been studied using polarized light microscopy. concentration within the droplet is found to be constant and therefore pitch independent total concentration. size grows as power law DNA. exponent relation calculated progressive nucleation growth model. equal two-thirds good agreement with experimental data. By analysing fields at low...
The time-dependent rate <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>I</mml:mi><mml:mo>(</mml:mo><mml:mi>t</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:math> of origin firing per length unreplicated DNA presents a universal bell shape in eukaryotes that has been interpreted as the result complex time-evolving interaction between origins and limiting factors. Here, we show normal diffusion replication fork components towards localized potential (p-oris) can more...
Abstract The activation of eukaryotic DNA replication origins needs to be strictly controlled at multiple steps in order faithfully duplicate the genome and maintain its stability. How checkpoint recovery adaptation protein Polo-like kinase 1 (Plk1) regulates firing during non-challenged S phase remained an open question. Using fiber analysis, we show that immunodepletion Plk1 Xenopus vitro system decreases fork density initiation frequency. Numerical analyses suggest reduces overall...
Recent studies of eukaryotic DNA replication timing profiles suggest that the time-dependent rate origin firing, I(t), has a universal shape, which ensures reproducible completion time. However, measurements I(t) are based on population averages, may bias shape because imperfect cell synchrony and cell-to-cell variability. Here, we measure population-averaged profile from synchronized Saccharomyces cerevisiae cells using combing extract single-cell numerical deconvolution. The single...
Using a combination of self assembly, Langmuir–Blodgett and Langmuir–Schaeffer techniques, we have produced multilayered film dimyristoylphosphatidylcholine (DMPC) intended for use as biomembrane mimic. Neutron reflectivity measurements revealed that the upper two layers phospholipid are separated from silicon substrate lower by hydration region approximately 30 Å thick. This layer limits tethering effect such molecules within bilayer significant freedom. freedom is evidenced fact shows...
Substitution of a polyelectrolyte for silica during formation surfactant-templated films produces similar nano- and macroscale structures confirming that acts as thin film self-assembly.
DNA replication in higher eukaryotes initiates at thousands of origins according to a spatio-temporal program. The ATR/Chk1 dependent checkpoint inhibits the activation later firing origins. In Xenopus vitro system initiations are not sequence and 2-5 grouped clusters that fire different times despite very short S phase. We have shown temporal program is stochastic level single clusters. It unclear how late but permits origin early Here, we analyze role Chk1 sperm nuclei replicating egg...