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  • S. - Z. Li, A. Vigouroux, M. Ahmar, A. El Sahili, L. Soulere, L. Sago, D. Cornu, S. Morera, et Y. Queneau, « Synthesis of a non-natural glucose-2-phosphate ester able to dupe the acc system of Agrobacterium fabrum », Organic & Biomolecular Chemistry, vol. 17, nᵒ 5, p. 1090-1096, févr. 2019.
    Résumé : The first non-natural derivative of the rare D-glucose-2-phosphate (G2P), namely glucose-2-(O-lactic acid phosphate) (G2LP), has been synthesized. When used as sole carbon source, G2LP enables bacterial growth of the plant pathogenic strain Agrobacterium fabrum C58 (formerly referred to as Agrobacterium tumefaciens). X-ray crystallography and affinity measurements investigations reveal that G2LP binds the periplasmic binding protein (PBP) AccA similarly to the natural compounds and with the same affinity. Moreover, enzymatic assays show that it is able to serve as substrate of the phosphodiesterase AccF. The properties found for G2LP demonstrate that the very unusual glucose-2-phosphoryl residue, present in G2LP, can be used as structural feature for designing non-natural systems fully compatible with the Acc cascade of A. fabrum.
    Mots-clés : B3S, diesters, glycogen, hydrolysis, MESB3S, opines, PF, phosphate, plasmids, SICAPS.

  • L. Pelosi, C. - D. - T. Vo, S. S. Abby, L. Loiseau, B. Rascalou, M. Hajj Chehade, B. Faivre, M. Goussé, C. Chenal, N. Touati, L. Binet, D. Cornu, C. D. Fyfe, M. Fontecave, F. Barras, M. Lombard, et F. Pierrel, « Ubiquinone Biosynthesis over the Entire O2 Range: Characterization of a Conserved O2-Independent Pathway », mBio, vol. 10, nᵒ 4, juill. 2019.
    Résumé : Most bacteria can generate ATP by respiratory metabolism, in which electrons are shuttled from reduced substrates to terminal electron acceptors, via quinone molecules like ubiquinone. Dioxygen (O2) is the terminal electron acceptor of aerobic respiration and serves as a co-substrate in the biosynthesis of ubiquinone. Here, we characterize a novel, O2-independent pathway for the biosynthesis of ubiquinone. This pathway relies on three proteins, UbiT (YhbT), UbiU (YhbU), and UbiV (YhbV). UbiT contains an SCP2 lipid-binding domain and is likely an accessory factor of the biosynthetic pathway, while UbiU and UbiV (UbiU-UbiV) are involved in hydroxylation reactions and represent a novel class of O2-independent hydroxylases. We demonstrate that UbiU-UbiV form a heterodimer, wherein each protein binds a 4Fe-4S cluster via conserved cysteines that are essential for activity. The UbiT, -U, and -V proteins are found in alpha-, beta-, and gammaproteobacterial clades, including several human pathogens, supporting the widespread distribution of a previously unrecognized capacity to synthesize ubiquinone in the absence of O2 Together, the O2-dependent and O2-independent ubiquinone biosynthesis pathways contribute to optimizing bacterial metabolism over the entire O2 range.IMPORTANCE In order to colonize environments with large O2 gradients or fluctuating O2 levels, bacteria have developed metabolic responses that remain incompletely understood. Such adaptations have been recently linked to antibiotic resistance, virulence, and the capacity to develop in complex ecosystems like the microbiota. Here, we identify a novel pathway for the biosynthesis of ubiquinone, a molecule with a key role in cellular bioenergetics. We link three uncharacterized genes of Escherichia coli to this pathway and show that the pathway functions independently from O2 In contrast, the long-described pathway for ubiquinone biosynthesis requires O2 as a substrate. In fact, we find that many proteobacteria are equipped with the O2-dependent and O2-independent pathways, supporting that they are able to synthesize ubiquinone over the entire O2 range. Overall, we propose that the novel O2-independent pathway is part of the metabolic plasticity developed by proteobacteria to face various environmental O2 levels.
    Mots-clés : bioenergetics, facultative anaerobes, hydroxylases, iron-sulfur, oxygen, peptidase U32, PF, proteobacteria, quinones, respiration, SICAPS, ubiquinone.


  • S. Blanchet, D. Cornu, I. Hatin, H. Grosjean, P. Bertin, et O. Namy, « Deciphering the reading of the genetic code by near-cognate tRNA », Proceedings of the National Academy of Sciences, vol. 115, nᵒ 12, p. 3018-3023, mars 2018.

  • B. Gronenborn, J. W. Randles, D. Knierim, Q. Barrière, H. J. Vetten, N. Warthmann, D. Cornu, T. Sileye, S. Winter, et T. Timchenko, « Analysis of DNAs associated with coconut foliar decay disease implicates a unique single-stranded DNA virus representing a new taxon », Scientific Reports, vol. 8, nᵒ 1, p. 5698, 2018.
    Mots-clés : MICROBIO, PBI, PF, SICAPS.

  • Á. Szabó, C. Papin, D. Cornu, E. Chélot, Z. Lipinszki, A. Udvardy, V. Redeker, U. Mayor, et F. Rouyer, « Ubiquitylation Dynamics of the Clock Cell Proteome and TIMELESS during a Circadian Cycle », Cell Reports, vol. 23, nᵒ 8, p. 2273-2282, mai 2018.
    Résumé : Circadian clocks have evolved as time-measuring molecular devices to help organisms adapt their physiology to daily changes in light and temperature. Transcriptional oscillations account for a large fraction of rhythmic protein abundance. However, cycling of various posttranslational modifications, such as ubiquitylation, also contributes to shape the rhythmic protein landscape. In this study, we used an in vivo ubiquitin labeling assay to investigate the circadian ubiquitylated proteome of Drosophila melanogaster. We find that cyclic ubiquitylation affects MEGATOR (MTOR), a chromatin-associated nucleoporin that, in turn, feeds back to regulate the core molecular oscillator. Furthermore, we show that the ubiquitin ligase subunits CULLIN-3 (CUL-3) and SUPERNUMERARY LIMBS (SLMB) cooperate for ubiquitylating the TIMELESS protein. These findings stress the importance of ubiquitylation pathways in the Drosophila circadian clock and reveal a key component of this system.
    Mots-clés : circadian clock, Drosophila, oscillation, PF, protein degradation, proteomics, SICAPS, ubiquitin, ubiquitin ligase.


  • C. Bou-Nader, D. Cornu, V. Guerineau, T. Fogeron, M. Fontecave, et D. Hamdane, « Enzyme Activation with a Synthetic Catalytic Co-enzyme Intermediate: Nucleotide Methylation by Flavoenzymes », Angewandte Chemie (International Ed. in English), août 2017.
    Résumé : To facilitate production of functional enzymes and to study their mechanisms, especially in the complex cases of coenzyme-dependent systems, activation of an inactive apoenzyme preparation with a catalytically competent coenzyme intermediate is an attractive strategy. This is illustrated with the simple chemical synthesis of a flavin-methylene iminium compound previously proposed as a key intermediate in the catalytic cycle of several important flavoenzymes involved in nucleic acid metabolism. Reconstitution of both flavin-dependent RNA methyltransferase and thymidylate synthase apoproteins with this synthetic compound led to active enzymes for the C5-uracil methylation within their respective transfer RNA and dUMP substrate. This strategy is expected to be of general application in enzymology.
    Mots-clés : artificial enzymes, flavoenzyme mechanism, Methylation, Nucleotides, PF, reaction intermediates, SICAPS.

  • C. Bou-Nader, L. Pecqueur, D. Cornu, M. Lombard, M. Dezi, M. Nicaise, C. Velours, M. Fontecave, et D. Hamdane, « Power of protein/tRNA functional assembly against aberrant aggregation », Physical chemistry chemical physics: PCCP, oct. 2017.
    Résumé : Understanding the mechanisms of protein oligomerization and aggregation is a major concern for biotechnology and medical purposes. However, significant challenges remain in determining the mechanism of formation of these superstructures and the environmental factors that can precisely modulate them. Notably the role that a functional ligand plays in the process of protein aggregation is largely unexplored. We herein address these issues with an original flavin-dependent RNA methyltransferase (TrmFO) used as a protein model since this protein employs a complex set of cofactors and ligands for catalysis. Here, we show that TrmFO carries an unstable protein structure that can partially mis-unfold leading to either formation of irregular and nonfunctional soluble oligomers endowed with hyper-thermal stability or large amorphous aggregates in the presence of salts. Mutagenesis confirmed that this peculiarity is an intrinsic property of a polypeptide and it is independent of the flavin coenzyme. Structural characterization and kinetic studies identified several regions of the protein that enjoy conformational changes and more particularly pinpointed the N-terminal subdomain as being a key element in the mechanisms of oligomerization and aggregation. Only stabilization of this region via tRNA suppresses these aberrant protein states. Although protein chaperones emerged as major actors against aggregation, our study emphasizes that other powerful mechanisms exist such as the stabilizing effect of functional assemblies that provide an additional layer of protection against the instability of the proteome.
    Mots-clés : PF, PIM, SICAPS.

  • L. Loiseau, C. Fyfe, L. Aussel, M. Hajj Chehade, S. B. Hernández, B. Faivre, D. Hamdane, C. Mellot-Draznieks, B. Rascalou, L. Pelosi, C. Velours, D. Cornu, M. Lombard, J. Casadesús, F. Pierrel, M. Fontecave, et F. Barras, « The UbiK protein is an accessory factor necessary for bacterial ubiquinone (UQ) biosynthesis and forms a complex with the UQ biogenesis factor UbiJ », The Journal of Biological Chemistry, mai 2017.
    Résumé : Ubiquinone (UQ), also referred to as coenzyme Q, is a widespread lipophilic molecule in both prokaryotes and eukaryotes in which it primarily acts as an electron carrier. Eleven proteins are known to participate in UQ biosynthesis in Escherichia coli, and we recently demonstrated that UQ biosynthesis requires additional, nonenzymatic factors, some of which are still unknown. Here, we report on the identification of a bacterial gene, yqiC, which is required for efficient UQ biosynthesis, and which we have renamed ubiK. Using several methods, we demonstrated that the UbiK protein forms a complex with the C-terminal part of UbiJ, another UQ biogenesis factor we previously identified. We found that both proteins are likely to contribute to global UQ biosynthesis rather than to a specific biosynthetic step, since both ubiK and ubiJ mutants accumulated octaprenylphenol, an early intermediate of the UQ biosynthetic pathway. Interestingly, we found that both proteins are dispensable for UQ biosynthesis under anaerobiosis, even though they were expressed in the absence of oxygen. We also provide evidence that the UbiK-UbiJ complex interacts with palmitoleic acid, a major lipid in E. coli. Last, in Salmonella enterica, ubiK was required for proliferation in macrophages and virulence in mice. We conclude that although the role of the UbiK-UbiJ complex remains unknown, our results support the hypothesis that UbiK is an accessory factor of Ubi enzymes and facilitates UQ biosynthesis by acting as an assembly factor, a targeting factor, or both.
    Mots-clés : bioenergetics, coenzyme Q10 (CoQ10), Electron transfer, Escherichia coli (E. coli), Microbiology, PF, PIM, SICAPS, Ubiquinone.


  • 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, févr. 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.

  • 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, oct. 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.

  • 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, sept. 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.

  • 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, juill. 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.

  • 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, juill. 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.

  • 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, mai 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.


  • 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, oct. 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.

  • 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.
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