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Publications plate-forme I2BC


  • S. C. Brown, M. Bourge, N. Maunoury, M. Wong, M. W. Bianchi, S. Lepers-Andrzejewski, P. Besse, S. Siljak-Yakovlev, M. Dron, et B. Satiat-Jeunemaître, « DNA remodelling by Strict Partial Endoreplication in orchids, an original process in the plant kingdom », Genome Biology and Evolution, 2017.
    Résumé : DNA remodelling during endoreplication appears to be a strong developmental characteristic in orchids. In this study, we analysed DNA content and nuclei in 41 species of orchids to further map the genome evolution in this plant family. We demonstrate that the DNA remodelling observed in 36 out of 41 orchids studied corresponds to strict partial endoreplication. Such process is developmentally regulated in each wild species studied. Cytometry data analyses allowed us to propose a model where nuclear states 2C, 4E, 8E, etc. form a series comprising a fixed proportion, the euploid genome 2C, plus 2 to 32 additional copies of a complementary part of the genome. The fixed proportion ranged from 89% of the genome in Vanilla mexicana down to 19% in V. pompona, the lowest value for all 148 orchids reported. Insterspecific hybridisation did not suppress this phenomenon. Interestingly, this process was not observed in mass-produced epiphytes. Nucleolar volumes grow with the number of endocopies present, coherent with high transcription activity in endoreplicated nuclei. Our analyses suggest species-specific chromatin rearrangement. Towards understanding endoreplication, V. planifolia constitutes a tractable system for isolating the genomic sequences that confer an advantage via endoreplication from those that apparently suffice at diploid level.
    Mots-clés : BIOCELL, CYTO, cytogenetics, cytometry, DYNBSJ, endoreplication, genome imbalance, Genome Size, PF, Vanilla.

  • E. Dambroise, M. Simion, T. Bourquard, S. Bouffard, B. Rizzi, Y. Jaszczyszyn, M. Bourge, P. Affaticati, A. Heuzé, J. Jouralet, J. Edouard, S. Brown, C. Thermes, A. Poupon, E. Reiter, F. Sohm, F. Bourrat, et J. - S. Joly, « Postembryonic Fish Brain Proliferation Zones Exhibit Neuroepithelial-Type Gene Expression Profile: Features of Neuroepithelial Cells in Fish », STEM CELLS, 2017.
    Mots-clés : BMgif, CYTO, NGS, PF.

  • T. Di Meo, W. Ghattas, C. Herrero, C. Velours, P. Minard, J. - P. Mahy, R. Ricoux, et A. Urvoas, « αRep A3: A versatile artificial scaffold for metalloenzyme design », Chemistry (Weinheim an Der Bergstrasse, Germany), 2017.
    Résumé : αRep is a new family of artificial proteins based on a thermostable alpha-helical repeated motif. One of its members, αRep A3, forms a stable homo-dimer with a wide cleft that is able to receive metal complexes and thus appears as suitable for generating new artificial biocatalysts. Based on the crystal structure of αRep A3, two positions (F119 and Y26) were chosen and changed independently into cysteine residues. A phenanthroline ligand was covalently attached to the unique cysteine of each protein variant and the corresponding biohybrids were purified and characterized. Once mutated and coupled to phenanthroline, the protein remained folded and dimeric. Copper(II) was bound specifically by the two biohybrids with two different binding modes and, in addition, the holo biohybrid A3F119NPH was found to be able to catalyze enantioselectively the Diels-Alder (D-A) cycloaddition with up to 62% ee. This study validates the choice of the αRep A3 dimer as a protein scaffold and provides a new promising route for the design and production of new enantioselective biohybrids based on entirely artificial proteins issued from a highly diverse library.
    Mots-clés : artificial repeat proteins, B3S, Diels-Alder reaction, Enantioselective Catalysis, MIP, PF, PIM.

  • R. El Helou, G. Pinna, O. Cabaud, J. Wicinski, R. Bhajun, L. Guyon, C. Rioualen, P. Finetti, A. Gros, B. Mari, P. Barbry, F. Bertucci, G. Bidaut, A. Harel-Bellan, D. Birnbaum, E. Charafe-Jauffret, et C. Ginestier, « miR-600 Acts as a Bimodal Switch that Regulates Breast Cancer Stem Cell Fate through WNT Signaling », Cell Reports, vol. 18, nᵒ 9, p. 2256-2268, 2017.

  • C. Esnault, D. Leiber, C. Toffano-Nioche, Z. Tanfin, et M. - J. Virolle, « Another example of enzymatic promiscuity: the polyphosphate kinase of Streptomyces lividans is endowed with phospholipase D activity », Applied Microbiology and Biotechnology, vol. 101, nᵒ 1, p. 139-145, 2017.
    Résumé : Polyphosphate kinases (PPK) from different bacteria, including that of Streptomyces lividans, were shown to contain the typical HKD motif present in phospholipase D (PLD) and showed structural similarities to the latter. This observation prompted us to investigate the PLD activity of PPK of S. lividans, in vitro. The ability of PPK to catalyze the hydrolysis of phosphatidylcholine (PC), the PLD substrate, was assessed by the quantification of [(3)H]phosphatidic acid (PA) released from [(3)H]PC-labeled ELT3 cell membranes. Basal cell membrane PLD activity as well as GTPγS-activated PLD activity was higher in the presence than in absence of PPK. After abolition of the basal PLD activity of the membranes by heat or tryptic treatment, the addition of PPK to cell membranes was still accompanied by an increased production of PA demonstrating that PPK also bears a PLD activity. PLD activity of PPK was also assessed by the production of choline from hydrolysis of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) in the presence of the Amplex Red reagent and compared to two commercial PLD enzymes. These data demonstrated that PPK is endowed with a weak but clearly detectable PLD activity. The question of the biological signification, if any, of this enzymatic promiscuity is discussed.
    Mots-clés : Amino Acid Motifs, Cell Membrane, Choline, eBio, Hydrolysis, Lipid droplets, MESMIC, MICROBIO, PF, Phosphatidic Acids, Phosphatidylcholines, Phospholipase D, Phosphotransferases (Phosphate Group Acceptor), Polyphosphate kinase, Promiscuous enzyme, Protein Conformation, Streptomyces lividans.

  • J. Lang, A. Vigouroux, A. El Sahili, A. Kwasiborski, M. Aumont-Nicaise, Y. Dessaux, J. A. Shykoff, S. Moréra, et D. Faure, « Fitness costs restrict niche expansion by generalist niche-constructing pathogens », The ISME Journal, vol. 11, nᵒ 2, p. 374-385, 2017.
    Mots-clés : B3S, MESB3S, MICROBIO, PBI, PF, PIM.

  • J. Marion, R. Le Bars, B. Satiat-Jeunemaitre, et C. Boulogne, « Optimizing CLEM protocols for plants cells: GMA embedding and cryosections as alternatives for preservation of GFP fluorescence in Arabidopsis roots », Journal of Structural Biology, 2017.
    Mots-clés : Arabidopsis, BIOCELL, Correlative microscopy, DYNBSJ, GFP, GMA resin, MET, PF, PHOT, Tokuyasu, Transmission electron microscopy.

  • J. - A. Pedroza-García, C. Mazubert, I. del Olmo, M. Bourge, S. Domenichini, R. Bounon, Z. Tariq, E. Delannoy, M. Piñeiro, J. A. Jarillo, C. Bergounioux, M. Benhamed, et C. Raynaud, « Function of the Plant DNA Polymerase Epsilon in Replicative Stress Sensing, a Genetic Analysis », Plant Physiology, vol. 173, nᵒ 3, p. 1735-1749, 2017.

  • P. Pétriacq, L. de Bont, L. Genestout, J. Hao, C. Laureau, I. Florez-Sarasa, T. Rzigui, G. Queval, F. Gilard, C. Mauve, F. Guérard, M. Lamothe-Sibold, J. Marion, C. Fresneau, S. Brown, A. Danon, A. Krieger-Liszkay, R. Berthomé, M. Ribas-Carbo, G. Tcherkez, G. Cornic, B. Pineau, B. Gakière, et R. De Paepe, « Photoperiod Affects the Phenotype of Mitochondrial Complex I Mutants », Plant Physiology, vol. 173, nᵒ 1, p. 434-455, 2017.
    Mots-clés : B3S, BIOCELL, DYNBSJ, MROP, PF, PHOT.

  • C. Samson, F. Celli, K. Hendriks, M. Zinke, N. Essawy, I. Herrada, A. - A. Arteni, F. - X. Theillet, B. Alpha-Bazin, J. Armengaud, C. Coirault, A. Lange, et S. Zinn-Justin, « Emerin self-assembly mechanism: role of the LEM domain », The FEBS Journal, vol. 284, nᵒ 2, p. 338-352, 2017.
    Mots-clés : B3S, CRYO, INTGEN, PF.

  • P. V. Sauer, J. Timm, D. Liu, D. Sitbon, E. Boeri-Erba, C. Velours, N. Mücke, J. Langowski, F. Ochsenbein, G. Almouzni, et D. Panne, « Insights into the molecular architecture and histone H3-H4 deposition mechanism of yeast Chromatin assembly factor 1 », eLife, vol. 6, mars 2017.
    Mots-clés : AMIG, B3S, PF, PIM.

  • Z. M. Song, L. Bouchab, E. Hudik, R. Le Bars, O. Nüsse, et S. Dupré-Crochet, « Phosphoinositol 3-phosphate acts as a timer for reactive oxygen species production in the phagosome », Journal of Leukocyte Biology, p. jlb.1A0716-305R, janv. 2017.

  • A. Talagas, L. Fontaine, L. Ledesma-García, J. Mignolet, I. Li de la Sierra-Gallay, N. Lazar, M. Aumont-Nicaise, M. J. Federle, G. Prehna, P. Hols, et S. Nessler, « Correction: Structural Insights into Streptococcal Competence Regulation by the Cell-to-Cell Communication System ComRS », PLOS Pathogens, vol. 13, nᵒ 2, p. e1006208, févr. 2017.
    Mots-clés : B3S, FAAM, PF, PIM.


  • S. Ahmad, L. Pecqueur, B. Dreier, D. Hamdane, M. Aumont-Nicaise, A. Plückthun, M. Knossow, et B. Gigant, « Destabilizing an interacting motif strengthens the association of a designed ankyrin repeat protein with tubulin », Scientific Reports, vol. 6, p. 28922, juill. 2016.
    Mots-clés : B3S, MIKICA, PF, PIM.

  • C. Aillaud, C. Bosc, Y. Saoudi, E. Denarier, L. Peris, L. Sago, N. Taulet, A. Cieren, O. Tort, M. M. Magiera, C. Janke, V. Redeker, A. Andrieux, et M. - J. Moutin, « Evidence for new C-terminally truncated variants of α- and β-tubulins », Molecular Biology of the Cell, vol. 27, nᵒ 4, p. 640-653, 2016.
    Résumé : Cellular α-tubulin can bear various carboxy-terminal sequences: full-length tubulin arising from gene neosynthesis is tyrosinated, and two truncated variants, corresponding to detyrosinated and Δ2 α‑tubulin, result from the sequential cleavage of one or two C-terminal residues, respectively. Here, by using a novel antibody named 3EG that is highly specific to the -EEEG C-terminal sequence, we demonstrate the occurrence in neuronal tissues of a new αΔ3‑tubulin variant corresponding to α1A/B‑tubulin deleted of its last three residues (EEY). αΔ3‑tubulin has a specific distribution pattern: its quantity in the brain is similar to that of αΔ2-tubulin around birth but is much lower in adult tissue. This truncated α1A/B-tubulin variant can be generated from αΔ2-tubulin by the deglutamylases CCP1, CCP4, CCP5, and CCP6 but not by CCP2 and CCP3. Moreover, using 3EG antibody, we identify a C‑terminally truncated β-tubulin form with the same -EEEG C-terminal sequence. Using mass spectrometry, we demonstrate that β2A/B-tubulin is modified by truncation of the four C-terminal residues (EDEA). We show that this newly identified βΔ4-tubulin is ubiquitously present in cells and tissues and that its level is constant throughout the cell cycle. These new C-terminally truncated α- and β-tubulin variants, both ending with -EEEG sequence, are expected to regulate microtubule physiology. Of interest, the αΔ3-tubulin seems to be related to dynamic microtubules, resembling tyrosinated-tubulin rather than the other truncated variants, and may have critical function(s) in neuronal development.
    Mots-clés : Amino Acid Sequence, Animals, Brain, Carboxypeptidases, cell cycle, Gene Knockdown Techniques, HEK293 Cells, HeLa Cells, Humans, Mass Spectrometry, Mice, Microtubules, Molecular Sequence Data, Neurogenesis, Neurons, Peptide Synthases, PF, Protein Processing, Post-Translational, SICAPS, Tubulin, Tyrosine.

  • M. Benincasa, Q. Barrière, G. Runti, O. Pierre, M. Bourge, M. Scocchi, et P. Mergaert, « Single Cell Flow Cytometry Assay for Peptide Uptake by Bacteria », BIO-PROTOCOL, vol. 6, nᵒ 23, 2016.
    Mots-clés : CYTO, MICROBIO, PBI, PF.

  • C. Chaintreuil, D. Gully, C. Hervouet, P. Tittabutr, H. Randriambanona, S. C. Brown, G. P. Lewis, M. Bourge, F. Cartieaux, M. Boursot, H. Ramanankierana, A. D'Hont, N. Teaumroong, E. Giraud, et J. - F. Arrighi, « The evolutionary dynamics of ancient and recent polyploidy in the African semiaquatic species of the legume genus Aeschynomene », The New Phytologist, vol. 211, nᵒ 3, p. 1077-1091, 2016.
    Résumé : The legume genus Aeschynomene is notable in the ability of certain semiaquatic species to develop nitrogen-fixing stem nodules. These species are distributed in two clades. In the first clade, all the species are characterized by the use of a unique Nod-independent symbiotic process. In the second clade, the species use a Nod-dependent symbiotic process and some of them display a profuse stem nodulation as exemplified in the African Aeschynomene afraspera. To facilitate the molecular analysis of the symbiotic characteristics of such legumes, we took an integrated molecular and cytogenetic approach to track occurrences of polyploidy events and to analyze their impact on the evolution of the African species of Aeschynomene. Our results revealed two rounds of polyploidy: a paleopolyploid event predating the African group and two neopolyploid speciations, along with significant chromosomal variations. Hence, we found that A. afraspera (8x) has inherited the contrasted genomic properties and the stem-nodulation habit of its parental lineages (4x). This study reveals a comprehensive picture of African Aeschynomene diversification. It notably evidences a history that is distinct from the diploid Nod-independent clade, providing clues for the identification of the specific determinants of the Nod-dependent and Nod-independent symbiotic processes, and for comparative analysis of stem nodulation.
    Mots-clés : Aeschynomene, CYTO, dysploidy, genome downsizing, PF, Polyploidy, stem nodulation, Symbiosis.

  • A. de Saint Germain, G. Clavé, M. - A. Badet-Denisot, J. - P. Pillot, D. Cornu, J. - P. Le Caer, M. Burger, F. Pelissier, P. Retailleau, C. Turnbull, S. Bonhomme, J. Chory, C. Rameau, et F. - D. Boyer, « An histidine covalent receptor and butenolide complex mediates strigolactone perception », Nature Chemical Biology, vol. 12, nᵒ 10, p. 787-794, 2016.
    Résumé : Strigolactone plant hormones control plant architecture and are key players in both symbiotic and parasitic interactions. They contain an ABC tricyclic lactone connected to a butenolide group, the D ring. The DWARF14 (D14) strigolactone receptor belongs to the superfamily of α/β-hydrolases, and is known to hydrolyze the bond between the ABC lactone and the D ring. Here we characterized the binding and catalytic functions of RAMOSUS3 (RMS3), the pea (Pisum sativum) ortholog of rice (Oryza sativa) D14 strigolactone receptor. Using new profluorescent probes with strigolactone-like bioactivity, we found that RMS3 acts as a single-turnover enzyme that explains its apparent low enzymatic rate. We demonstrated the formation of a covalent RMS3-D-ring complex, essential for bioactivity, in which the D ring was attached to histidine 247 of the catalytic triad. These results reveal an undescribed mechanism of plant hormone reception in which the receptor performs an irreversible enzymatic reaction to generate its own ligand.
    Mots-clés : PF, SICAPS.

  • E. Deforzh, T. Vargas, J. Kropp, M. Vandamme, G. Pinna, et A. Polesskaya, « IMP-3 protects the mRNAs of cyclins D1 and D3 from GW182/AGO2-dependent translational repression », International Journal of Oncology, oct. 2016.
    Mots-clés : DBG, PARI, PF, RPTEG.

  • T. Eychenne, E. Novikova, M. - B. Barrault, O. Alibert, C. Boschiero, N. Peixeiro, D. Cornu, V. Redeker, L. Kuras, P. Nicolas, M. Werner, et J. Soutourina, « Functional interplay between Mediator and TFIIB in preinitiation complex assembly in relation to promoter architecture », Genes & Development, vol. 30, nᵒ 18, p. 2119-2132, 2016.
    Résumé : Mediator is a large coregulator complex conserved from yeast to humans and involved in many human diseases, including cancers. Together with general transcription factors, it stimulates preinitiation complex (PIC) formation and activates RNA polymerase II (Pol II) transcription. In this study, we analyzed how Mediator acts in PIC assembly using in vivo, in vitro, and in silico approaches. We revealed an essential function of the Mediator middle module exerted through its Med10 subunit, implicating a key interaction between Mediator and TFIIB. We showed that this Mediator-TFIIB link has a global role on PIC assembly genome-wide. Moreover, the amplitude of Mediator's effect on PIC formation is gene-dependent and is related to the promoter architecture in terms of TATA elements, nucleosome occupancy, and dynamics. This study thus provides mechanistic insights into the coordinated function of Mediator and TFIIB in PIC assembly in different chromatin contexts.
    Mots-clés : DBG, GTR, Mediator, PEPS, PF, preinitiation complex, promoter architecture, RNA polymerase II transcription, Saccharomyces cerevisiae, SICAPS, TFIIB.

  • E. Galli, M. Poidevin, R. Le Bars, J. - M. Desfontaines, L. Muresan, E. Paly, Y. Yamaichi, et F. - X. Barre, « Cell division licensing in the multi-chromosomal Vibrio cholerae bacterium », Nature Microbiology, vol. 1, nᵒ 9, p. 16094, juin 2016.
    Mots-clés : DBG, EMC2, EQYY, PF, PHOT.

  • J. Hai, N. Serradji, L. Mouton, V. Redeker, D. Cornu, J. - M. El Hage Chahine, P. Verbeke, et M. Hémadi, « Targeted Delivery of Amoxicillin to C. trachomatis by the Transferrin Iron Acquisition Pathway », PloS One, vol. 11, nᵒ 2, p. e0150031, 2016.
    Résumé : Weak intracellular penetration of antibiotics makes some infections difficult to treat. The Trojan horse strategy for targeted drug delivery is among the interesting routes being explored to overcome this therapeutic difficulty. Chlamydia trachomatis, as an obligate intracellular human pathogen, is responsible for both trachoma and sexually transmitted diseases. Chlamydia develops in a vacuole and is therefore protected by four membranes (plasma membrane, bacterial inclusion membrane, and bacterial membranes). In this work, the iron-transport protein, human serum-transferrin, was used as a Trojan horse for antibiotic delivery into the bacterial vacuole. Amoxicillin was grafted onto transferrin. The transferrin-amoxicillin construct was characterized by mass spectrometry and absorption spectroscopy. Its affinity for transferrin receptor 1, determined by fluorescence emission titration [KaffTf-amox = (1.3 ± 1.0) x 108], is very close to that of transferrin [4.3 x 108]. Transmission electron and confocal microscopies showed a co-localization of transferrin with the bacteria in the vacuole and were also used to evaluate the antibiotic capability of the construct. It is significantly more effective than amoxicillin alone. These promising results demonstrate targeted delivery of amoxicillin to suppress Chlamydia and are of interest for Chlamydiaceae and maybe other intracellular bacteria therapies.
    Mots-clés : Amoxicillin, Anti-Bacterial Agents, Chlamydia Infections, Chlamydia trachomatis, Drug Delivery Systems, Humans, Iron, PF, SICAPS, Trachoma, Transferrin, Vacuoles.

  • D. Hamdane, C. Velours, D. Cornu, M. Nicaise, M. Lombard, et M. Fontecave, « A chemical chaperone induces inhomogeneous conformational changes in flexible proteins », Physical chemistry chemical physics: PCCP, vol. 18, nᵒ 30, p. 20410-20421, 2016.
    Résumé : Organic osmolytes also known as chemical chaperones are major cellular compounds that favor, by an unclear mechanism, protein's compaction and stabilization of the native state. Here, we have examined the chaperone effect of the naturally occurring trimethylamine N-oxide (TMAO) osmolyte on a loosely packed protein (LPP), known to be a highly flexible form, using an apoprotein mutant of the flavin-dependent RNA methyltransferase as a model. Thermal and chemical denaturation experiments showed that TMAO stabilizes the structural integrity of the apoprotein dramatically. The denaturation reaction is irreversible indicating that the stability of the apoprotein is under kinetic control. This result implies that the stabilization is due to a TMAO-induced reconfiguration of the flexible LPP state, which leads to conformational limitations of the apoprotein likely driven by favorable entropic contribution. Evidence for the conformational perturbation of the apoprotein had been obtained through several biophysical approaches notably analytical ultracentrifugation, circular dichroism, fluorescence spectroscopy, labelling experiments and proteolysis coupled to mass spectrometry. Unexpectedly, TMAO promotes an overall elongation or asymmetrical changes of the hydrodynamic shape of the apoprotein without alteration of the secondary structure. The modulation of the hydrodynamic properties of the protein is associated with diverse inhomogenous conformational changes: loss of the solvent accessible cavities resulting in a dried protein matrix; some side-chain residues initially buried become solvent exposed while some others become hidden. Consequently, the TMAO-induced protein state exhibits impaired capability in the flavin binding process. Our study suggests that the nature of protein conformational changes induced by the chemical chaperones may be specific to protein packing and plasticity. This could be an efficient mechanism by which the cell controls and finely tunes the conformation of the marginally stable LPPs to avoid their inappropriate protein/protein interactions and aggregation.
    Mots-clés : PF, PIM, SICAPS.

  • T. N. Le Lam, C. Morvan, W. Liu, C. Bohn, Y. Jaszczyszyn, et P. Bouloc, « Finding sRNA-associated phenotypes by competition assays: An example with Staphylococcus aureus », Methods, 2016.
    Mots-clés : DBG, NGS, PF, SRRB.

  • P. Maisonnasse, E. Bouguyon, G. Piton, A. Ezquerra, C. Urien, C. Deloizy, M. Bourge, J. - J. Leplat, G. Simon, C. Chevalier, S. Vincent-Naulleau, E. Crisci, M. Montoya, I. Schwartz-Cornil, et N. Bertho, « The respiratory DC/macrophage network at steady-state and upon influenza infection in the swine biomedical model », Mucosal Immunology, vol. 9, nᵒ 4, p. 835-849, 2016.

  • L. Marty, A. Vigouroux, M. Aumont-Nicaise, Y. Dessaux, D. Faure, et S. Moréra, « Structural Basis for High Specificity of Amadori Compound and Mannopine Opine Binding in Bacterial Pathogens », The Journal of Biological Chemistry, vol. 291, nᵒ 43, p. 22638-22649, 2016.
    Résumé : Agrobacterium tumefaciens pathogens genetically modify their host plants to drive the synthesis of opines in plant tumors. Opines are either sugar phosphodiesters or the products of condensed amino acids with ketoacids or sugars. They are Agrobacterium nutrients and imported into the bacterial cell via periplasmic-binding proteins (PBPs) and ABC-transporters. Mannopine, an opine from the mannityl-opine family, is synthesized from an intermediate named deoxy-fructosyl-glutamine (DFG), which is also an opine and abundant Amadori compound (a name used for any derivative of aminodeoxysugars) present in decaying plant materials. The PBP MotA is responsible for mannopine import in mannopine-assimilating agrobacteria. In the nopaline-opine type agrobacteria strain, SocA protein was proposed as a putative mannopine binding PBP, and AttC protein was annotated as a mannopine binding-like PBP. Structural data on mannityl-opine-PBP complexes is currently lacking. By combining affinity data with analysis of seven x-ray structures at high resolution, we investigated the molecular basis of MotA, SocA, and AttC interactions with mannopine and its DFG precursor. Our work demonstrates that AttC is not a mannopine-binding protein and reveals a specific binding pocket for DFG in SocA with an affinity in nanomolar range. Hence, mannopine would not be imported into nopaline-type agrobacteria strains. In contrast, MotA binds both mannopine and DFG. We thus defined one mannopine and two DFG binding signatures. Unlike mannopine-PBPs, selective DFG-PBPs are present in a wide diversity of bacteria, including Actinobacteria, α-,β-, and γ-proteobacteria, revealing a common role of this Amadori compound in pathogenic, symbiotic, and opportunistic bacteria.
    Mots-clés : ABC transporter, B3S, Crystal Structure, DFG, host-pathogen interaction, isothermal titration calorimetry (ITC), mannopine, MESB3S, opine, periplasmic binding protein, PF, PIM, plant pathogen, x-ray crystallography.

  • J. A. Pedroza-Garcia, S. Domenichini, C. Mazubert, M. Bourge, C. White, E. Hudik, R. Bounon, Z. Tariq, E. Delannoy, I. del Olmo, M. Piñeiro, J. A. Jarillo, C. Bergounioux, M. Benhamed, et C. Raynaud, « Role of the Polymerase ϵ sub-unit DPB2 in DNA replication, cell cycle regulation and DNA damage response in Arabidopsis », Nucleic Acids Research, p. gkw449, mai 2016.

  • N. Petryk, M. Kahli, Y. d'Aubenton-Carafa, Y. Jaszczyszyn, Y. Shen, M. Silvain, C. Thermes, C. - L. Chen, et O. Hyrien, « Replication landscape of the human genome », Nature Communications, vol. 7, p. 10208, janv. 2016.

  • A. Polesskaya, G. Pinna, Y. Sassi, M. Vandamme, A. Bigot, V. Mouly, N. Morozova, A. Harel-Bellan, et C. Degerny, « Post-transcriptional modulation of interleukin 8 by CNOT6L regulates skeletal muscle differentiation », Biochimica Et Biophysica Acta (BBA) -Molecular Cell Research, vol. 1863, nᵒ 2, p. 263-270, 2016.
    Résumé : CNOT6L is a deadenylase subunit belonging to the CCR4-NOT complex, a major deadenylase complex in eukaryotes involved at multiple levels in regulation of gene expression. While CNOT6L is expressed in skeletal muscle cells, its specific functions in this tissue are still largely unknown. Our previous work highlighted the functional of CNOT6L in skeletal muscle cell differentiation. To further explore how CNOT6L regulates myogenesis, we used here gene expression analysis to identify CNOT6L mRNA targets in human myoblasts. Among these novel targets, IL-8 (interleukin 8) mRNA was the most upregulated in CNOT6L knock-down (KD) cells. Biochemical approaches and poly (A) tail length assays showed that IL-8 mRNA is a direct target of CNOT6L, and further investigations by loss- and gain-of-function assays pointed out that IL-8 is an important effector of myogenesis. Therefore, we have characterized CNOT6L-IL-8 as a new signaling axis that regulates myogenesis.
    Mots-clés : Adult, Animals, Blotting, Western, Cell Differentiation, Cell Line, Cells, Cultured, CNOT6L, DBG, Differentiation, Gene Expression Profiling, Humans, IL-8, Interleukin-8, Microscopy, Fluorescence, Muscle Development, Muscle Fibers, Skeletal, Muscle, Skeletal, Myoblasts, Myogenesis, Oligonucleotide Array Sequence Analysis, PARIS, PF, Post-transcriptional regulation, Reverse Transcriptase Polymerase Chain Reaction, Ribonucleases, RNA Interference, RNA, Messenger, RPTEG, Signal Transduction, Transcription, Genetic.

  • A. Rémion, F. Khoder-Agha, D. Cornu, M. Argentini, V. Redeker, et M. Mirande, « Identification of protein interfaces within the multi-aminoacyl-tRNA synthetase complex: the case of lysyl-tRNA synthetase and the scaffold protein p38 », FEBS open bio, vol. 6, nᵒ 7, p. 696-706, 2016.
    Résumé : Human cytoplasmic lysyl-tRNA synthetase (LysRS) is associated within a multi-aminoacyl-tRNA synthetase complex (MSC). Within this complex, the p38 component is the scaffold protein that binds the catalytic domain of LysRS via its N-terminal region. In addition to its translational function when associated to the MSC, LysRS is also recruited in nontranslational roles after dissociation from the MSC. The balance between its MSC-associated and MSC-dissociated states is essential to regulate the functions of LysRS in cellular homeostasis. With the aim of understanding the rules that govern association of LysRS in the MSC, we analyzed the protein interfaces between LysRS and the full-length version of p38, the scaffold protein of the MSC. In a previous study, the cocrystal structure of LysRS with a N-terminal peptide of p38 was reported [Ofir-Birin Y et al. (2013) Mol Cell 49, 30-42]. In order to identify amino acid residues involved in interaction of the two proteins, the non-natural, photo-cross-linkable amino acid p-benzoyl-l-phenylalanine (Bpa) was incorporated at 27 discrete positions within the catalytic domain of LysRS. Among the 27 distinct LysRS mutants, only those with Bpa inserted in place of Lys356 or His364 were cross-linked with p38. Using mass spectrometry, we unambiguously identified the protein interface of the cross-linked complex and showed that Lys356 and His364 of LysRS interact with the peptide from Pro8 to Arg26 in native p38, in agreement with the published cocrystal structure. This interface, which in LysRS is located on the opposite side of the dimer to the site of interaction with its tRNA substrate, defines the core region of the MSC. The residues identified herein in human LysRS are not conserved in yeast LysRS, an enzyme that does not associate within the MSC, and contrast with the residues proposed to be essential for LysRS:p38 association in the earlier work.
    Mots-clés : cross‐link, DBG, lysyl‐tRNA synthetase, MARS, multisynthetase complex, p38, PF, protein:protein interaction, SICAPS.

  • A. Talagas, L. Fontaine, L. Ledesma-Garca, J. Mignolet, I. Li de la Sierra-Gallay, N. Lazar, M. Aumont-Nicaise, M. J. Federle, G. Prehna, P. Hols, et S. Nessler, « Structural Insights into Streptococcal Competence Regulation by the Cell-to-Cell Communication System ComRS », PLOS Pathogens, vol. 12, nᵒ 12, p. e1005980, déc. 2016.
    Mots-clés : B3S, FAAM, PF, PIM.

  • V. D. T. Tran, O. Souiai, N. Romero-Barrios, M. Crespi, et D. Gautheret, « Detection of generic differential RNA processing events from RNA-seq data », RNA Biology, vol. 13, nᵒ 1, p. 59-67, janv. 2016.
    Mots-clés : DBG, eBio, PF, SSFA.

  • M. Wery, M. Descrimes, N. Vogt, A. - S. Dallongeville, D. Gautheret, et A. Morillon, « Nonsense-Mediated Decay Restricts LncRNA Levels in Yeast Unless Blocked by Double-Stranded RNA Structure », Molecular Cell, vol. 61, nᵒ 3, p. 379-392, 2016.
    Mots-clés : DBG, eBio, PF, SSFA.

  • Z. Yi, M. Manil-Ségalen, L. Sago, A. Glatigny, V. Redeker, R. Legouis, et M. - H. Mucchielli-Giorgi, « SAFER, an Analysis Method of Quantitative Proteomic Data, Reveals New Interactors of the C. elegans Autophagic Protein LGG-1 », Journal of Proteome Research, vol. 15, nᵒ 5, p. 1515-1523, 2016.
    Résumé : Affinity purifications followed by mass spectrometric analysis are used to identify protein-protein interactions. Because quantitative proteomic data are noisy, it is necessary to develop statistical methods to eliminate false-positives and identify true partners. We present here a novel approach for filtering false interactors, named "SAFER" for mass Spectrometry data Analysis by Filtering of Experimental Replicates, which is based on the reproducibility of the replicates and the fold-change of the protein intensities between bait and control. To identify regulators or targets of autophagy, we characterized the interactors of LGG1, a ubiquitin-like protein involved in autophagosome formation in C. elegans. LGG-1 partners were purified by affinity, analyzed by nanoLC-MS/MS mass spectrometry, and quantified by a label-free proteomic approach based on the mass spectrometric signal intensity of peptide precursor ions. Because the selection of confident interactions depends on the method used for statistical analysis, we compared SAFER with several statistical tests and different scoring algorithms on this set of data. We show that SAFER recovers high-confidence interactors that have been ignored by the other methods and identified new candidates involved in the autophagy process. We further validated our method on a public data set and conclude that SAFER notably improves the identification of protein interactors.
    Mots-clés : atg-8/LC3, Autophagy, BIM, BIOCELL, C. elegans, DBG, label free mass spectrometry, OTOFAG, PF, proteomics, SICAPS, statistical methodology.


  • A. - A. Arteni, M. Fradot, D. Galzerano, M. M. Mendes-Pinto, J. - A. Sahel, S. Picaud, B. Robert, et A. A. Pascal, « Structure and Conformation of the Carotenoids in Human Retinal Macular Pigment », PLOS ONE, vol. 10, nᵒ 8, p. e0135779, août 2015.
    Mots-clés : B3S, Humans, LBMS, Lutein, Macular Pigment, Molecular Conformation, PF, Retinal Pigments, SE, Spectrum Analysis, Raman, Zeaxanthins.

  • C. Bourbousse, I. Mestiri, G. Zabulon, M. Bourge, F. Formiggini, M. A. Koini, S. C. Brown, P. Fransz, C. Bowler, et F. Barneche, « Light signaling controls nuclear architecture reorganization during seedling establishment », Proceedings of the National Academy of Sciences, vol. 112, nᵒ 21, p. E2836-E2844, mai 2015.

  • M. Bourge, C. Fort, M. - N. Soler, B. Satiat-Jeunemaître, et S. C. Brown, « A pulse-chase strategy combining click-EdU and photoconvertible fluorescent reporter: tracking Golgi protein dynamics during the cell cycle », New Phytologist, vol. 205, nᵒ 2, p. 938-950, 2015.
    Mots-clés : 5-ethynyl-2′-deoxyuridine (EdU), Arabidopsis, cell cycle, Cell Proliferation, Click Chemistry, Copper, CYTO, Deoxyuridine, Fluorescence, Fluorescent Dyes, fluorescent proteins, G1 subcompartments, Golgi Apparatus, Golgi synthesis, Green Fluorescent Proteins, Kaede pulse-chase, Luminescent Proteins, Molecular Imaging, PF, PHOT, Plant Proteins, Plants, Genetically Modified, Protoplasts, Tobacco, tobacco (Nicotiana tabacum) BY2 cells.

  • A. Chevrel, A. Urvoas, I. L. de la Sierra-Gallay, M. Aumont-Nicaise, S. Moutel, M. Desmadril, F. Perez, A. Gautreau, H. van Tilbeurgh, P. Minard, et M. Valerio-Lepiniec, « Specific GFP-binding artificial proteins ( Rep): a new tool for in vitro to live cell applications », Bioscience Reports, vol. 35, nᵒ 4, p. e00223-e00223, août 2015.
    Mots-clés : B3S, FAAM, MIP, PF, PIM.

  • M. Descrimes, Y. Ben Zouari, M. Wery, R. Legendre, D. Gautheret, et A. Morillon, « VING: a software for visualization of deep sequencing signals », BMC research notes, vol. 8, p. 419, 2015.
    Résumé : BACKGROUND: Next generation sequencing (NGS) data treatment often requires mapping sequenced reads onto a reference genome for further analysis. Mapped data are commonly visualized using genome browsers. However, such software are not suited for a publication-ready and versatile representation of NGS data coverage, especially when multiple experiments are simultaneously treated. RESULTS: We developed 'VING', a stand-alone R script that takes as input NGS mapping files and genome annotations to produce accurate snapshots of the NGS coverage signal for any specified genomic region. VING offers multiple viewing options, including strand-specific views and a special heatmap mode for representing multiple experiments in a single figure. CONCLUSIONS: VING produces high-quality figures for NGS data representation in a genome region of interest. It is available at We also developed a Galaxy wrapper, available in the Galaxy tool shed with installation and usage instructions.
    Mots-clés : Computational Biology, eBio, Genome, Genomics, High-Throughput Nucleotide Sequencing, Internet, PF, Reproducibility of Results, Sequence Analysis, DNA, Software.

  • A. El Sahili, A. Kwasiborski, N. Mothe, C. Velours, P. Legrand, S. Moréra, et D. Faure, « Natural Guided Genome Engineering Reveals Transcriptional Regulators Controlling Quorum-Sensing Signal Degradation », PLOS ONE, vol. 10, nᵒ 11, p. e0141718, nov. 2015.
    Mots-clés : 4-Butyrolactone, Amino Acid Sequence, Amino Acid Substitution, B3S, Bacterial Proteins, Carboxylic Ester Hydrolases, Circular Dichroism, Crystallography, X-Ray, Directed Molecular Evolution, Gene Expression Regulation, Bacterial, Homoserine, Lactones, MESB3S, MICROBIO, Molecular Sequence Data, Mutation, Mutation, Missense, PBI, PF, PIM, Point Mutation, Polymorphism, Single Nucleotide, Protein Conformation, Protein Folding, Quorum Sensing, Rhodococcus, Transcription Factors, Transcription, Genetic.

  • F. Eyboulet, S. Wydau-Dematteis, T. Eychenne, O. Alibert, H. Neil, C. Boschiero, M. - C. Nevers, H. Volland, D. Cornu, V. Redeker, M. Werner, et J. Soutourina, « Mediator independently orchestrates multiple steps of preinitiation complex assembly in vivo », Nucleic Acids Research, vol. 43, nᵒ 19, p. 9214-9231, 2015.
    Résumé : Mediator is a large multiprotein complex conserved in all eukaryotes, which has a crucial coregulator function in transcription by RNA polymerase II (Pol II). However, the molecular mechanisms of its action in vivo remain to be understood. Med17 is an essential and central component of the Mediator head module. In this work, we utilised our large collection of conditional temperature-sensitive med17 mutants to investigate Mediator's role in coordinating preinitiation complex (PIC) formation in vivo at the genome level after a transfer to a non-permissive temperature for 45 minutes. The effect of a yeast mutation proposed to be equivalent to the human Med17-L371P responsible for infantile cerebral atrophy was also analyzed. The ChIP-seq results demonstrate that med17 mutations differentially affected the global presence of several PIC components including Mediator, TBP, TFIIH modules and Pol II. Our data show that Mediator stabilizes TFIIK kinase and TFIIH core modules independently, suggesting that the recruitment or the stability of TFIIH modules is regulated independently on yeast genome. We demonstrate that Mediator selectively contributes to TBP recruitment or stabilization to chromatin. This study provides an extensive genome-wide view of Mediator's role in PIC formation, suggesting that Mediator coordinates multiple steps of a PIC assembly pathway.
    Mots-clés : Chromatin, DBG, Galactokinase, Gene Expression Regulation, Fungal, Genome, Fungal, GTR, Mediator Complex, Mutation, PF, RNA Polymerase II, RNA, Messenger, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, SICAPS, TATA-Box Binding Protein, Transcription Factor TFIIH, Transcription Initiation, Genetic.

  • A. Gall, A. A. Pascal, et B. Robert, « Vibrational techniques applied to photosynthesis: Resonance Raman and fluorescence line-narrowing », Biochimica et Biophysica Acta (BBA) - Bioenergetics, vol. 1847, nᵒ 1, p. 12-18, 2015.
    Mots-clés : B3S, carotenoid, Carotenoids, Chlorophyll, LBMS, Light-harvesting, PF, photosynthesis, Pigments, Biological, Reaction center, Spectrometry, Fluorescence, Spectrum Analysis, Raman, SV, Vibration.

  • L. Garcia, F. Cisnetti, N. Gillet, R. Guillot, M. Aumont-Nicaise, J. - P. Piquemal, M. Desmadril, F. Lambert, et C. Policar, « Entasis through hook-and-loop fastening in a glycoligand with cumulative weak forces stabilizing Cu(I) », Journal of the American Chemical Society, vol. 137, nᵒ 3, p. 1141-1146, 2015.
    Résumé : The idea of a possible control of metal ion properties by constraining the coordination sphere geometry was introduced by Vallee and Williams with the concept of entasis, which is frequently postulated to be at stake in metallobiomolecules. However, the interactions controlling the geometry at metal centers remain often elusive. In this study, the coordination properties toward copper ions—Cu(II) or Cu(I)—of a geometrically constrained glycoligand centered on a sugar scaffold were compared with those of an analogous ligand built on an unconstrained alkyl chain. The sugar-centered ligand was shown to be more preorganized for Cu(II) coordination than its open-chain analogue, with an unusual additional stabilization of the Cu(I) redox state. This preference for Cu(I) was suggested to arise from geometric constraints favoring an optimized folding of the glycoligand minimizing steric repulsions. In other words, the Cu(I) d(10) species is stabilized by valence shell electron pair repulsion (VSEPR). This idea was rationalized by a theoretical noncovalent interactions (NCI) analysis. The cumulative effects of weak forces were shown to create an efficient buckle as in a hook-and-loop fastener, and fine structural features within the glycoligand reduce repulsive interactions for the Cu(I) state. This study emphasizes that monosaccharide platforms are appropriate ligand backbones for a delicate geometric control at the metal center, with a network of weak interactions within the ligand. This structuration availing in glycoligands makes them attractive for metallic entasis.
    Mots-clés : Carbohydrates, Copper, Ligands, Models, Molecular, Molecular Structure, Organometallic Compounds, PF, PIM.

  • U. Gophna, D. M. Kristensen, Y. I. Wolf, O. Popa, C. Drevet, et E. V. Koonin, « No evidence of inhibition of horizontal gene transfer by CRISPR-Cas on evolutionary timescales », The ISME journal, vol. 9, nᵒ 9, p. 2021-2027, 2015.
    Résumé : The CRISPR (clustered, regularly, interspaced, short, palindromic repeats)-Cas (CRISPR-associated genes) systems of archaea and bacteria provide adaptive immunity against viruses and other selfish elements and are believed to curtail horizontal gene transfer (HGT). Limiting acquisition of new genetic material could be one of the sources of the fitness cost of CRISPR-Cas maintenance and one of the causes of the patchy distribution of CRISPR-Cas among bacteria, and across environments. We sought to test the hypothesis that the activity of CRISPR-Cas in microbes is negatively correlated with the extent of recent HGT. Using three independent measures of HGT, we found no significant dependence between the length of CRISPR arrays, which reflects the activity of the immune system, and the estimated number of recent HGT events. In contrast, we observed a significant negative dependence between the estimated extent of HGT and growth temperature of microbes, which could be explained by the lower genetic diversity in hotter environments. We hypothesize that the relevant events in the evolution of resistance to mobile elements and proclivity for HGT, to which CRISPR-Cas systems seem to substantially contribute, occur on the population scale rather than on the timescale of species evolution.
    Mots-clés : Adaptive Immunity, Archaea, bacteria, Biological Evolution, Clustered Regularly Interspaced Short Palindromic Repeats, CRISPR-Cas Systems, eBio, Gene Transfer, Horizontal, Genome, Bacterial, Models, Genetic, PF, Temperature, Viruses.

  • I. Guefrachi, O. Pierre, T. Timchenko, B. Alunni, Q. Barrière, P. Czernic, J. - A. Villaécija-Aguilar, C. Verly, M. Bourge, J. Fardoux, M. Mars, E. Kondorosi, E. Giraud, et P. Mergaert, « Bradyrhizobium BclA Is a Peptide Transporter Required for Bacterial Differentiation in Symbiosis with Aeschynomene Legumes », Molecular plant-microbe interactions: MPMI, vol. 28, nᵒ 11, p. 1155-1166, 2015.
    Résumé : Nodules of legume plants are highly integrated symbiotic systems shaped by millions of years of evolution. They harbor nitrogen-fixing rhizobium bacteria called bacteroids. Several legume species produce peptides called nodule-specific cysteine-rich (NCR) peptides in the symbiotic nodule cells which house the bacteroids. NCR peptides are related to antimicrobial peptides of innate immunity. They induce the endosymbionts into a differentiated, enlarged, and polyploid state. The bacterial symbionts, on their side, evolved functions for the response to the NCR peptides. Here, we identified the bclA gene of Bradyrhizobium sp. strains ORS278 and ORS285, which is required for the formation of differentiated and functional bacteroids in the nodules of the NCR peptide-producing Aeschynomene legumes. The BclA ABC transporter promotes the import of NCR peptides and provides protection against the antimicrobial activity of these peptides. Moreover, BclA can complement the role of the related BacA transporter of Sinorhizobium meliloti, which has a similar symbiotic function in the interaction with Medicago legumes.
    Mots-clés : Bacterial Proteins, Bradyrhizobium, CYTO, Fabaceae, Flow Cytometry, Genetic Complementation Test, Host-Pathogen Interactions, Medicago, Membrane Transport Proteins, MICROBIO, Microscopy, Confocal, Molecular Sequence Data, Mutation, PBI, Peptides, PF, Phylogeny, Polyploidy, Root Nodules, Plant, Sinorhizobium meliloti, Symbiosis.

  • L. Guyon, C. Lajaunie, F. Fer, R. Bhajun, E. Sulpice, G. Pinna, A. Campalans, J. P. Radicella, P. Rouillier, M. Mary, S. Combe, P. Obeid, J. - P. Vert, et X. Gidrol, « Φ-score: A cell-to-cell phenotypic scoring method for sensitive and selective hit discovery in cell-based assays », Scientific Reports, vol. 5, nᵒ 1, 2015.

  • A. Hajrudinović, S. Siljak-Yakovlev, S. C. Brown, F. Pustahija, M. Bourge, D. Ballian, et F. Bogunić, « When sexual meets apomict: genome size, ploidy level and reproductive mode variation of Sorbus aria s.l. and S. austriaca (Rosaceae) in Bosnia and Herzegovina », Annals of Botany, vol. 116, nᵒ 2, p. 301-312, 2015.
    Résumé : BACKGROUND AND AIMS: Allopolyploidy and intraspecific heteroploid crosses are associated, in certain groups, with changes in the mating system. The genus Sorbus represents an appropriate model to study the relationships between ploidy and reproductive mode variations. Diploid S. aria and tetraploid apomictic S. austriaca were screened for ploidy and mating system variations within pure and sympatric populations in order to gain insights into their putative causalities. METHODS: Flow cytometry was used to assess genome size and ploidy level among 380 S. aria s.l. and S. austriaca individuals from Bosnia and Herzegovina, with 303 single-seed flow cytometric seed screenings being performed to identify their mating system. Pollen viability and seed set were also determined. KEY RESULTS: Flow cytometry confirmed the presence of di-, tri- and tetraploid cytotype mixtures in mixed-ploidy populations of S. aria and S. austriaca. No ploidy variation was detected in single-species populations. Diploid S. aria mother plants always produced sexually originated seeds, whereas tetraploid S. austriaca as well as triploid S. aria were obligate apomicts. Tetraploid S. aria preserved sexuality in a low portion of plants. A tendency towards a balanced 2m : 1p parental genome contribution to the endosperm was shared by diploids and tetraploids, regardless of their sexual or asexual origin. In contrast, most triploids apparently tolerated endosperm imbalance. CONCLUSIONS: Coexistence of apomictic tetraploids and sexual diploids drives the production of novel polyploid cytotypes with predominantly apomictic reproductive modes. The data suggest that processes governing cytotype diversity and mating system variation in Sorbus from Bosnia and Herzegovina are probably parallel to those in other diversity hotspots of this genus. The results represent a solid contribution to knowledge of the reproduction of Sorbus and will inform future investigations of the molecular and genetic mechanisms involved in triggering and regulating cytotype diversity and alteration of reproductive modes.
    Mots-clés : Apomixis, Bosnia and Herzegovina, Cell Nucleus, CYTO, cytotypes, DNA, Plant, Endosperm, Flow Cytometry, Genome Size, Geography, PF, Ploidies, Pollen, Polyploidy, reproduction, reproduction mode, Rosaceae., Seeds, sexuality, Sorbus, Sorbus aria, Sorbus austriaca.

  • D. Hamdane, C. Bou-Nader, D. Cornu, G. Hui-Bon-Hoa, et M. Fontecave, « Flavin–Protein Complexes: Aromatic Stacking Assisted by a Hydrogen Bond », Biochemistry, vol. 54, nᵒ 28, p. 4354-4364, juill. 2015.
    Mots-clés : Amino Acid Sequence, Bacillus subtilis, Catalytic Domain, Flavin-Adenine Dinucleotide, Flavins, Hydrogen Bonding, Methylation, Models, Molecular, Molecular Sequence Data, Oxidation-Reduction, PF, Protein Conformation, SICAPS, tRNA Methyltransferases, Tyrosine.

  • I. Herrada, C. Samson, C. Velours, L. Renault, C. Östlund, P. Chervy, D. Puchkov, H. J. Worman, B. Buendia, et S. Zinn-Justin, « Muscular Dystrophy Mutations Impair the Nuclear Envelope Emerin Self-assembly Properties », ACS chemical biology, vol. 10, nᵒ 12, p. 2733-2742, 2015.
    Résumé : More than 100 genetic mutations causing X-linked Emery-Dreifuss muscular dystrophy have been identified in the gene encoding the integral inner nuclear membrane protein emerin. Most mutations are nonsense or frameshift mutations that lead to the absence of emerin in cells. Only very few cases are due to missense or short in-frame deletions. Molecular mechanisms explaining the corresponding emerin variants' loss of function are particularly difficult to identify because of the mostly intrinsically disordered state of the emerin nucleoplasmic region. We now demonstrate that this EmN region can be produced as a disordered monomer, as revealed by nuclear magnetic resonance, but rapidly self-assembles in vitro. Increases in concentration and temperature favor the formation of long curvilinear filaments with diameters of approximately 10 nm, as observed by electron microscopy. Assembly of these filaments can be followed by fluorescence through Thioflavin-T binding and by Fourier-transform Infrared spectrometry through formation of β-structures. Analysis of the assembly properties of five EmN variants reveals that del95-99 and Q133H impact filament assembly capacities. In cells, these variants are located at the nuclear envelope, but the corresponding quantities of emerin-emerin and emerin-lamin proximities are decreased compared to wild-type protein. Furthermore, variant P183H favors EmN aggregation in vitro, and variant P183T provokes emerin accumulation in cytoplasmic foci in cells. Substitution of residue Pro183 might systematically favor oligomerization, leading to emerin aggregation and mislocalization in cells. Our results suggest that emerin self-assembly is necessary for its proper function and that a loss of either the protein itself or its ability to self-assemble causes muscular dystrophy.
    Mots-clés : ACTIN, B3S, Genetic Variation, HeLa Cells, Humans, Hydrophobic and Hydrophilic Interactions, INTGEN, Magnetic Resonance Spectroscopy, Membrane Proteins, Muscular Dystrophies, Nuclear Envelope, Nuclear Proteins, PF, PIM, Proteostasis Deficiencies, Spectroscopy, Fourier Transform Infrared.

  • T. Jégu, S. Domenichini, T. Blein, F. Ariel, A. Christ, S. - K. Kim, M. Crespi, S. Boutet-Mercey, G. Mouille, M. Bourge, H. Hirt, C. Bergounioux, C. Raynaud, et M. Benhamed, « A SWI/SNF Chromatin Remodelling Protein Controls Cytokinin Production through the Regulation of Chromatin Architecture », PLOS ONE, vol. 10, nᵒ 10, p. e0138276, oct. 2015.
    Mots-clés : Alkyl and Aryl Transferases, Arabidopsis, Arabidopsis Proteins, Carrier Proteins, cell cycle, Chromatin, Chromatin Assembly and Disassembly, Chromosomal Proteins, Non-Histone, CYTO, Cytokinins, DNA, Plant, Epigenesis, Genetic, Genetic Loci, Histones, Meristem, PF.

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