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6 results on '"Elodie Chatre"'

1. RNAP II antagonizes mitotic chromatin folding and chromosome segregation by condensin

Author

Jérémy Lebreton, Léonard Colin, Elodie Chatre, and Pascal Bernard

Subjects
CP: Molecular biology, Biology (General), QH301-705.5
Abstract

Summary: Condensin shapes mitotic chromosomes by folding chromatin into loops, but whether it does so by DNA-loop extrusion remains speculative. Although loop-extruding cohesin is stalled by transcription, the impact of transcription on condensin, which is enriched at highly expressed genes in many species, remains unclear. Using degrons of Rpb1 or the torpedo nuclease Dhp1XRN2 to either deplete or displace RNAPII on chromatin in fission yeast metaphase cells, we show that RNAPII does not load condensin on DNA. Instead, RNAPII retains condensin in cis and hinders its ability to fold mitotic chromatin and to support chromosome segregation, consistent with the stalling of a loop extruder. Transcription termination by Dhp1 limits such a hindrance. Our results shed light on the integrated functioning of condensin, and we argue that a tight control of transcription underlies mitotic chromosome assembly by loop-extruding condensin.

Published
2024
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2. Cinématique de réorientation de E. coli à proximité d'une surface solide

Author

Cao Cuong Nguyen, Christophe Place, Cédric Vaillant, Elodie Chatre, T. Cajgfinger, Jean-François Palierne, Laurence Lemelle, Agnes Dominjon, Remi Barbier, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique de l'ENS Lyon (Phys-ENS), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Claude Bernard Lyon 1 (UCBL), École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Surface (mathematics), Physics, 0303 health sciences, Models, Statistical, High magnification, Chemotaxis, Solid surface, [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], Biophysics, Geometry, Kinematics, Thermal diffusivity, Models, Biological, [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, Article, Biomechanical Phenomena, 03 medical and health sciences, 0302 clinical medicine, Flagella, 13. Climate action, Escherichia coli, High temporal resolution, Clockwise, 030217 neurology & neurosurgery, 030304 developmental biology
Abstract

International audience; Bacteria tumble periodically, following environmental cues. Whether they can tumble near a solid surface is a basic issue for the inception of infection or mineral biofouling. Observing freely swimming Escherichia coli near and parallel to a glass surface imaged at high magnification (Â100) and high temporal resolution (500 Hz), we identified tumbles as events starting (or finishing, respectively) in abrupt deceleration (or reacceleration, respectively) of the body motion. Selected events show an equiprobable clockwise (CW) or counterclockwise change in direction that is superimposed on a surface CW path because of persistent propulsion. These tumbles follow a common long (about 300 5 100 ms, N ¼ 52) deceleration-reorientation acceleration pattern. A wavelet transform multiscale analysis shows these tumbles cause in-plane diffusive reorientations with 1.5 rad 2 /s rotational diffusivity, a value that compares with that measured in bulk tumbles. In half of the cases, additional few-millisecond bursts of an almost equiprobable CW or counterclockwise change of direction (12 5 90 , N ¼ 89) occur within the reorientation stage. The highly dispersed absolute values of change of direction (70 5 66 , N ¼ 89) of only a few bursts destabilize the cell-swimming direction. These first observations of surface tumbles set a foundation for statistical models of run-and-tumble surface motion different from that in bulk and lend support for chemotaxis near solid surface.

Published
2020

3. Synthesis of multifunctional lipid-polymer conjugates: application to the elaboration of bright far-red fluorescent lipid probes

Author

Cyril Favard, Elodie Chatre, Chantal Andraud, Marie-Thérèse Charreyre, Salim Adjili, Yann Bretonnière, Julien Massin, Delphine Muriaux, Christophe Place, Arnaud Favier, Yi-Chun Lin, William Lacour, Ingénierie des Matériaux Polymères (IMP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet [Saint-Étienne] (UJM)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon, Laboratoire de Chimie - UMR5182 (LC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), Laboratoire Joliot Curie, École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique de l'ENS Lyon (Phys-ENS), École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Institut de Recherche en Infectiologie de Montpellier (IRIM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), IMBM, Virologie humaine, École normale supérieure - Lyon (ENS Lyon)-IFR128-Institut National de la Santé et de la Recherche Médicale (INSERM)-École normale supérieure - Lyon (ENS Lyon)-IFR128-Institut National de la Santé et de la Recherche Médicale (INSERM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure de Lyon (ENS de Lyon)-IFR128-Institut National de la Santé et de la Recherche Médicale (INSERM)-École normale supérieure de Lyon (ENS de Lyon)-IFR128-Institut National de la Santé et de la Recherche Médicale (INSERM)

Subjects
chemistry.chemical_classification, Liposome, General Chemical Engineering, Phospholipid, Nanotechnology, General Chemistry, Polymer, [CHIM.MATE]Chemical Sciences/Material chemistry, Chromophore, Fluorescence, chemistry.chemical_compound, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Reversible addition−fragmentation chain-transfer polymerization, lipids (amino acids, peptides, and proteins), Lipid bilayer, Conjugate
Abstract

International audience; A new class of lipid-ended polymer conjugates presenting reactive sites regularly distributed along the polymer chain were synthesized using RAFT polymerization. The chosen modular approach enables preparation of different lipid families by tuning the nature of the phospholipid α-end, the molecular weight and the lateral functions of the polymer chain. The multiple activated ester functions of the conjugates can indeed be used for the efficient coupling of a great variety of amino-containing entities of interest. In this study, we elaborated original fluorescent lipid-polymer probes for optical microscopy by coupling along the chain a controlled number of chromophores emitting in the far-red where auto-fluorescence and light absorption by biological samples are limited. Water-soluble fluorescent lipid probes exhibiting an enhanced brightness were obtained. As a proof of concept, these probes were able to efficiently label the lipid bilayer of liposomes of various sizes. Such multifunctional lipid-ended polymers thus exhibit great potential to functionalize model and natural lipid assemblies.

Published
2014

4. Curvature reversal of the circular motion of swimming bacteria probes for slip at solid/liquid interfaces

Author

Laurence Lemelle, Jean-François Palierne, Elodie Chatre, Cédric Vaillant, Christophe Place, Laboratoire de Sciences de la Terre (LST), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique de l'ENS Lyon (Phys-ENS), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire Joliot Curie, École normale supérieure de Lyon (ENS de Lyon)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, and École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, [PHYS]Physics [physics], 0303 health sciences, Materials science, business.industry, Solid surface, Anchoring, 02 engineering and technology, General Chemistry, Mechanics, Polymer, Slip (materials science), 021001 nanoscience & nanotechnology, Condensed Matter Physics, Curvature, 03 medical and health sciences, Optics, Circular motion, chemistry, Boundary value problem, 0210 nano-technology, business, Solid liquid, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology
Abstract

The orientation of the circular motion of most swimming E. coli at a solid surface is shown to be (i) reversed by supplementing the medium with alginate and (ii) restored by rendering the glass surface positively charged. Given slip promotion by the polymer and suppression by its anchoring on the surface, observations are interpreted by slip at the boundary. This points out bacterial swimming as a probe of the solid/fluid boundary condition.

Published
2013

5. Role of polyadenylation in regulation of the flagella cascade and motility in Escherichia coli

Author

Laurence Lemelle, Céline Gracia, Philippe Hamman, Alexandre Maes, Dominique Bréchemier, Philippe N. Bertin, Elodie Chatre, and Eliane Hajnsdorf

Subjects
Membrane permeability, Polyadenylation, Transcription, Genetic, Mutant, Sigma Factor, Flagellum, medicine.disease_cause, Biochemistry, Microbiology, Bacterial Proteins, Transcription (biology), Vancomycin, Gene expression, medicine, Escherichia coli, Promoter Regions, Genetic, biology, Escherichia coli Proteins, Polynucleotide Adenylyltransferase, General Medicine, Gene Expression Regulation, Bacterial, Cell biology, Anti-Bacterial Agents, Flagella, Mutation, biology.protein, Trans-Activators, Flagellin
Abstract

Polyadenylation is recognized as part of a surveillance machinery for eliminating defective RNA molecules in eukaryotes and prokaryotes. Escherichia coli strains, deficient in poly(A)polymerase I (PAP I), expressed less flagellin compared to wild-type strains. Because flagellin synthesis is a late step in the flagellar biosynthesis pathway, we assessed the role of PAP I in this cascade and in flagella function. Transcription of flhDC, fliA, and fliC was decreased in the PAP I mutant. These results provide evidence that polyadenylation positively controls the expression of genes belonging to the flagellar biosynthesis pathway and that this effect is mediated through the FlhDC master regulator. However, the downshift in flagella gene expression in the mutant strain did not provoke any noticeable defects in the synthesis of flagella, in biofilm formation and in swimming speed although there was a reduction in motility on soft agar. Our data support an alternative hypothesis that the reduced motility of the mutant resulted from an alteration of the cell membrane composition caused in part by the higher level of GlmS (Glucosamine-6P synthase) which accumulates in the mutant. In agreement with this hypothesis the mutant is more sensitive to hydrophobic agents and antibiotics and in particular to vancomycin. We propose that PAP I participates in the ability of the bacteria to adapt to and survive detrimental conditions by constantly monitoring and adjusting to its environment.

Published
2012

6. Counterclockwise Circular Motion of Bacteria Swimming at the Air-Liquid Interface▿ † ‡

Author

Laurence Lemelle, Jean-François Palierne, Elodie Chatre, Christophe Place, Laboratoire de Sciences de la Terre (LST), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Laboratoire Joliot Curie, École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique de l'ENS Lyon (Phys-ENS), École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Centre National de la Recherche Scientifique (CNRS), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
SURFACE, Physiology and Metabolism, Slip (materials science), Biology, Propulsion, 01 natural sciences, Microbiology, 010305 fluids & plasmas, 03 medical and health sciences, Planar, Circular motion, MOTILITY, 0103 physical sciences, Escherichia coli, Clockwise, Molecular Biology, 030304 developmental biology, 0303 health sciences, Microscopy, Video, Air liquid interface, Solid surface, Anatomy, Mechanics, CHEMOTAXIS, [SDV.MP]Life Sciences [q-bio]/Microbiology and Parasitology, ESCHERICHIA-COLI, Flagella, human activities, Locomotion
Abstract

Flagellar propulsion of swimming Escherichia coli produces circling clockwise motions near planar solid surfaces. Counterclockwise motion was first reported near air-TN medium interfaces, showing that slip at the interface is a key parameter of bacterial swimming.

Published
2010

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