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Louvel G, Milewski C, Auzac G, Villaret F, Ung M, Berthelot K, Folino E, Ezra P, Roberti E, Yessoufou I, Cheve M, Fournier-Bidoz N, Paragios N, Deutsch E, Rivera S. PO-1099 To plan and deliver adjuvant breast radiotherapy over 1 week: 1-week breast workflow implementation. Radiother Oncol 2021. [DOI: 10.1016/s0167-8140(21)07550-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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2
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Mondini M, Hamon P, Loyher P, Gerbé de Thoré M, Clemenson C, Laviron M, Berthelot K, Salomon B, Combadière C, Boissonnas A, Deutsch E. OC-0082: TNFα-mediated crosstalk between regulatory T cells and monocytes limits radiotherapy efficacy. Radiother Oncol 2020. [DOI: 10.1016/s0167-8140(21)00108-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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3
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Henry C, Berthelot K, Lanneau C, Orsini C, Gorge-Bernat D, Meaux I, Chassin D, Moll J, Thiers B, Machnik D, Debussche L. Abstract 242: Identification of biomarkers predicting sensitivity to GLS1 inhibition using a CRISPR screen. Cancer Res 2020. [DOI: 10.1158/1538-7445.am2020-242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The conditional essential amino acid glutamine is utilized by tumors to sustain bioenergetic requirements in a nutrient-poor microenvironment. Based on this specific tumor need, efforts have been made to target the glutamine metabolism using glutaminase inhibitors. This approach has demonstrated activity in preclinical models and in a range of phase I studies. It was shown that a subset of models/patients are benefiting from glutaminase inhibition, however, biomarkers predicting sensitivity to GLS1 inhibitors are lacking. The objective of this study is to identify molecular predictors of the sensitivity towards GLS1 inhibition. Using the cBioportal, we analyzed the most prevalent genetic deficiencies in Triple Negative Breast cancers, Kidney cancers, Acute Myeloid Leukemia and Multiple Myeloma. From this analysis, a library of CRISPR gRNA including the most disease relevant LOF linked-genes was created. Individual cell lines stably expressing Cas9 were used for a focused CRISPR screen in the presence of suboptimal doses of GLS1 inhibitor. The sgRNA library mimicking the major genetic deficiencies identified from the cBioportal datamining was delivered in pool lentiviral particles. Genes deficiencies associated with increased GLS1 sensitivity were identified with sgRNA targeted NGS sequencing of the remaining cell population at treatment completion. We present the setup and validation of an innovative experimental design for the identification of biomarkers predictive to GLS1 inhibition with the aim to identify gene deficiencies associated with increased sensitivity to GLS1 inhibitors that could be used as predictive biomarkers in the clinic.
Citation Format: Christophe Henry, Karine Berthelot, Christophe Lanneau, Cécile Orsini, Dimitri Gorge-Bernat, Isabelle Meaux, Dorine Chassin, Jürgen Moll, Berangere Thiers, David Machnik, Laurent Debussche. Identification of biomarkers predicting sensitivity to GLS1 inhibition using a CRISPR screen [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 242.
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Marcireau C, Berthelot K, Williart A, Fournet H, Debono D, Thill G, Erasimus H, Chassin D, Lanneau C, Yaligara V, Orsini C, Didier M, Mikol V, Bouaboula M, Debussche L. Abstract 1272: Whole genome Crispr screening to identify potential SERD molecule resistance mechanisms. Cancer Res 2019. [DOI: 10.1158/1538-7445.am2019-1272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Metastatic breast cancer results in substantial morbidity and mortality for women afflicted with this disease. Approximately 80% of breast cancers express the estrogen receptor. The cancer cell survival and proliferation is driven by the activation of the estrogen receptor. SAR439859 is an effective endocrine therapy for breast cancer selectively and effectively degrading the estrogen receptor. A phase 1/2 study of SAR439859 alone and/or in combination with palbociclib in postmenopausal women with estrogen receptor positive advanced breast cancer was initiated last year by Sanofi.
CRISPR/Cas9 is a recent and revolutionary technology for efficient and directed alterations of the genome. CRISPR allows users to introduce DNA double-strand breaks at precise locations in the genome using complementary guide RNAs (SgRNA). These double strand breaks can be repaired by non-homologous end joining DNA repair mechanism. This DNA repair mechanism is an error prone DNA repair process which can lead to gene invalidation.
We aimed at investigating the potential SAR439859 resistance mechanisms. A better understanding of resistance mechanisms is needed to overcome this potential problem and to propose complementary therapeutic solutions. We conducted a whole genome CRISPR screening in a breast tumor cell line with a thermofisher commercial SgRNA library (ref: M04305) to identified genes involved in potential SAR439859 resistance phenomena. CRISPR screening steps will be presented from the cell line selections to results analysis.
Citation Format: Christophe Marcireau, Karine Berthelot, Alice Williart, Hamida Fournet, Delphine Debono, Gilbert Thill, Helene Erasimus, Dorine Chassin, Christophe Lanneau, Veeanagouda Yaligara, Cecile Orsini, Michel Didier, Vincent Mikol, Monsif Bouaboula, Laurent Debussche. Whole genome Crispr screening to identify potential SERD molecule resistance mechanisms [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1272.
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Reuzé S, Alexis A, Chargari C, Bockel S, Berthelot K, Escande A, Dumas I, Orlhac F, Haie-Meder C, Deutsch E, Robert C. OC-0075: A MRI radiomic signature for predicting brachytherapy outcomes in locally advanced cervical cancer. Radiother Oncol 2018. [DOI: 10.1016/s0167-8140(18)30385-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Reuzé S, Chargari C, Schernberg A, Seban R, Alexis A, Bockel S, Berthelot K, Escande A, Dercle L, Haie-Meder C, Deutsch E, Robert C. PO-0807: Diversity of PET imaging biomarkers predicting cervical cancer treatment outcome: where do we stand? Radiother Oncol 2018. [DOI: 10.1016/s0167-8140(18)31117-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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7
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Wadeesirisak K, Castano S, Berthelot K, Vaysse L, Bonfils F, Peruch F, Rattanaporn K, Liengprayoon S, Lecomte S, Bottier C. Rubber particle proteins REF1 and SRPP1 interact differently with native lipids extracted from Hevea brasiliensis latex. Biochimica et Biophysica Acta (BBA) - Biomembranes 2017; 1859:201-210. [DOI: 10.1016/j.bbamem.2016.11.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 11/11/2016] [Accepted: 11/18/2016] [Indexed: 02/07/2023]
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8
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Berthelot K, Thureau S, Giraud P. Détermination des marges du volume cible anatomoclinique au volume cible prévisionnel des cancers bronchiques en radiothérapie conformationnelle tridimensionnelle ou avec modulation d’intensité. Cancer Radiother 2016; 20:616-21. [DOI: 10.1016/j.canrad.2016.08.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 08/01/2016] [Indexed: 12/25/2022]
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9
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Berthelot K, Estevez Y, Quiliano M, Baldera-Aguayo PA, Zimic M, Pribat A, Bakleh ME, Teyssier E, Gallusci P, Gardrat C, Lecomte S, Peruch F. HbIDI, SlIDI and EcIDI: A comparative study of isopentenyl diphosphate isomerase activity and structure. Biochimie 2016; 127:133-43. [PMID: 27163845 DOI: 10.1016/j.biochi.2016.05.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/02/2016] [Indexed: 10/21/2022]
Abstract
In this study, we cloned, expressed and purified the isopentenyl diphosphate isomerases (IDIs) from two plants, Hevea brasiliensis and Solanum lycopersicum, and compared them to the already well characterized Escherichia coli IDI. Phylogenetic analysis showed high homology between the three enzymes. Their catalytic activity was investigated in vitro with recombinant purified enzymes and in vivo by complementation colorimetric tests. The three enzymes displayed consistent activities both in vitro and in vivo. In term of structure, studied by ATR-FTIR and molecular modeling, it is clear that both plant enzymes are more related to their human homologue than to E. coli IDI. But it is assumed that EcIDI represent the minimalistic part of the catalytic core, as both plant enzymes present a supplementary sequence forming an extra α-helice surrounding the catalytic site that could facilitate the biocatalysis. New potential biotechnological applications may be envisaged.
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Affiliation(s)
- Karine Berthelot
- CNRS, LCPO, UMR 5629, Univ. Bordeaux, Bordeaux INP, F-33600, Pessac, France; CNRS, CBMN, UMR 5248, Univ. Bordeaux, Bordeaux INP, F-33600, Pessac, France.
| | - Yannick Estevez
- CNRS, LCPO, UMR 5629, Univ. Bordeaux, Bordeaux INP, F-33600, Pessac, France
| | - Miguel Quiliano
- Departamento de Química Orgánica y Farmacéutica, Facultad de Farmacia y Nutrición, Universidad de Navarra, C/. Irunlarrea 1, 31008, Pamplona, Navarra, Spain
| | - Pedro A Baldera-Aguayo
- Department of Systems Biology and Integrated Program in Cellular, Molecular and Biomedical Studies, Columbia University in the City of New York, NY, 10032, USA; Laboratorio de Bioinformática y Biología Molecular, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, San Martin de Porres, Lima, 31, Peru
| | - Mirko Zimic
- Laboratorio de Bioinformática y Biología Molecular, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, San Martin de Porres, Lima, 31, Peru
| | - Anne Pribat
- INRA Bordeaux-Aquitaine, UMR 1332 Biologie du Fruit et Pathologie, F-33882, Villenave d'Ornon, France
| | - Marc-Elias Bakleh
- CNRS, LCPO, UMR 5629, Univ. Bordeaux, Bordeaux INP, F-33600, Pessac, France
| | - Emeline Teyssier
- Univ. Bordeaux, Grape Ecophysiology and Functional Biology Laboratory, ISVV, F-33882, Villenave d'Ornon, France
| | - Philippe Gallusci
- Univ. Bordeaux, Grape Ecophysiology and Functional Biology Laboratory, ISVV, F-33882, Villenave d'Ornon, France
| | - Christian Gardrat
- CNRS, LCPO, UMR 5629, Univ. Bordeaux, Bordeaux INP, F-33600, Pessac, France
| | - Sophie Lecomte
- CNRS, CBMN, UMR 5248, Univ. Bordeaux, Bordeaux INP, F-33600, Pessac, France
| | - Frédéric Peruch
- CNRS, LCPO, UMR 5629, Univ. Bordeaux, Bordeaux INP, F-33600, Pessac, France.
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Berthelot K, Lecomte S, Coulary-Salin B, Bentaleb A, Peruch F. Hevea brasiliensis prohevein possesses a conserved C-terminal domain with amyloid-like properties in vitro. Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 2016; 1864:388-99. [DOI: 10.1016/j.bbapap.2016.01.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 01/05/2016] [Accepted: 01/11/2016] [Indexed: 11/30/2022]
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11
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Nkhali L, Berthelot K, Gensanne D, Gérard M, Ammar L, Auvray H. Radiothérapie conformationnelle avec modulation d’intensité dans le canal anal : contrôle locorégional et évaluation de la toxicité. Cancer Radiother 2015. [DOI: 10.1016/j.canrad.2015.07.069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Berthelot K, Lecomte S, Estevez Y, Peruch F. Hevea brasiliensis REF (Hev b 1) and SRPP (Hev b 3): An overview on rubber particle proteins. Biochimie 2014; 106:1-9. [DOI: 10.1016/j.biochi.2014.07.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 07/05/2014] [Indexed: 11/28/2022]
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13
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Berthelot K, Lecomte S, Estevez Y, Zhendre V, Henry S, Thévenot J, Dufourc EJ, Alves ID, Peruch F. Rubber particle proteins, HbREF and HbSRPP, show different interactions with model membranes. Biochimica et Biophysica Acta (BBA) - Biomembranes 2014; 1838:287-99. [DOI: 10.1016/j.bbamem.2013.08.025] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 08/27/2013] [Accepted: 08/31/2013] [Indexed: 01/31/2023]
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Harté E, Maalouli N, Shalabney A, Texier E, Berthelot K, Lecomte S, Alves ID. Probing the kinetics of lipid membrane formation and the interaction of a nontoxic and a toxic amyloid with plasmon waveguide resonance. Chem Commun (Camb) 2014; 50:4168-71. [DOI: 10.1039/c4cc00571f] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The kinetics of formation of solid-supported lipid model membranes were investigated using a home-made plasmon waveguide resonance (PWR) sensor possessing enhanced properties relative to classic surface plasmon resonance sensors.
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Affiliation(s)
- E. Harté
- CBMN
- UMR 5248 CNRS
- Université de Bordeaux
- 33600 Pessac, France
| | - N. Maalouli
- Departamento de Química de los Materiales
- Universidad de Santiago de Chile
- Chile
| | - A. Shalabney
- ISIS
- Université de Strasbourg
- 67083 Strasbourg, France
| | - E. Texier
- CRPP
- Université de Bordeaux
- 33600 Pessac, France
| | - K. Berthelot
- LCPO UMR 5629 CNRS
- Université de Bordeaux
- 33600 Pessac, France
| | - S. Lecomte
- CBMN
- UMR 5248 CNRS
- Université de Bordeaux
- 33600 Pessac, France
| | - I. D. Alves
- CBMN
- UMR 5248 CNRS
- Université de Bordeaux
- 33600 Pessac, France
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Berthelot K, Cullin C, Lecomte S. What does make an amyloid toxic: Morphology, structure or interaction with membrane? Biochimie 2013; 95:12-9. [DOI: 10.1016/j.biochi.2012.07.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 07/10/2012] [Indexed: 01/21/2023]
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Berthelot K, Lecomte S, Estevez Y, Coulary-Salin B, Bentaleb A, Cullin C, Deffieux A, Peruch F. Rubber elongation factor (REF), a major allergen component in Hevea brasiliensis latex has amyloid properties. PLoS One 2012; 7:e48065. [PMID: 23133547 PMCID: PMC3485013 DOI: 10.1371/journal.pone.0048065] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 09/19/2012] [Indexed: 12/26/2022] Open
Abstract
REF (Hevb1) and SRPP (Hevb3) are two major components of Hevea brasiliensis latex, well known for their allergenic properties. They are obviously taking part in the biosynthesis of natural rubber, but their exact function is still unclear. They could be involved in defense/stress mechanisms after tapping or directly acting on the isoprenoid biosynthetic pathway. The structure of these two proteins is still not described. In this work, it was discovered that REF has amyloid properties, contrary to SRPP. We investigated their structure by CD, TEM, ATR-FTIR and WAXS and neatly showed the presence of β-sheet organized aggregates for REF, whereas SRPP mainly fold as a helical protein. Both proteins are highly hydrophobic but differ in their interaction with lipid monolayers used to mimic the monomembrane surrounding the rubber particles. Ellipsometry experiments showed that REF seems to penetrate deeply into the monolayer and SRPP only binds to the lipid surface. These results could therefore clarify the role of these two paralogous proteins in latex production, either in the coagulation of natural rubber or in stress-related responses. To our knowledge, this is the first report of an amyloid formed from a plant protein. This suggests also the presence of functional amyloid in the plant kingdom.
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Ricard C, Savary D, Decherf T, Berthelot K, Bare S. Défibrillateurs entièrement automatiques et survie des patients en arrêt cardiaque, Nord-Alpes. Rev Epidemiol Sante Publique 2012. [DOI: 10.1016/j.respe.2012.06.213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Berthelot K, Estevez Y, Deffieux A, Peruch F. Isopentenyl diphosphate isomerase: A checkpoint to isoprenoid biosynthesis. Biochimie 2012; 94:1621-34. [DOI: 10.1016/j.biochi.2012.03.021] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 03/27/2012] [Indexed: 11/25/2022]
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Ta HP, Berthelot K, Coulary-Salin B, Castano S, Desbat B, Bonnafous P, Lambert O, Alves I, Cullin C, Lecomte S. A yeast toxic mutant of HET-s amyloid disrupts membrane integrity. Biochim Biophys Acta 2012; 1818:2325-34. [PMID: 22562024 DOI: 10.1016/j.bbamem.2012.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 04/17/2012] [Accepted: 04/18/2012] [Indexed: 10/28/2022]
Abstract
Many studies have pointed out the interaction between amyloids and membranes, and their potential involvement in amyloid toxicity. Previously, we generated a yeast toxic amyloid mutant (M8) from the harmless amyloid protein by changing a few residues of the Prion Forming Domain of HET-s (PFD HET-s(218-289)) and clearly demonstrated the complete different behaviors of the non-toxic Wild Type (WT) and toxic amyloid (called M8) in terms of fiber morphology, aggregation kinetics and secondary structure. In this study, we compared the interaction of both proteins (WT and M8) with membrane models, as liposomes or supported bilayers. We first demonstrated that the toxic protein (M8) induces a significant leakage of liposomes formed with negatively charged lipids and promotes the formation of microdomains inside the lipid bilayer (as potential "amyloid raft"), whereas the non-toxic amyloid (WT) only binds to the membrane without further perturbations. The secondary structure of both amyloids interacting with membrane is preserved, but the anti-symmetric PO(2)(-) vibration is strongly shifted in the presence of M8. Secondly, we established that the presence of membrane models catalyzes the amyloidogenesis of both proteins. Cryo-TEM (cryo-transmission electron microscopy) images show the formation of long HET-s fibers attached to liposomes, whereas a large aggregation of the toxic M8 seems to promote a membrane disruption. This study allows us to conclude that the toxicity of the M8 mutant could be due to its high propensity to interact and disrupt lipid membranes.
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Affiliation(s)
- Ha Phuong Ta
- Université Bordeaux 1, Allée Geoffroy de Saint Hilaire, Pessac, France
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Berthelot K, Ta HP, Géan J, Lecomte S, Cullin C. In vivo and in vitro analyses of toxic mutants of HET-s: FTIR antiparallel signature correlates with amyloid toxicity. J Mol Biol 2011; 412:137-52. [PMID: 21782829 DOI: 10.1016/j.jmb.2011.07.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 07/04/2011] [Accepted: 07/06/2011] [Indexed: 01/11/2023]
Abstract
The folding and interactions of amyloid proteins are at the heart of the debate as to how these proteins may or may not become toxic to their host. Although little is known about this issue, the structure seems to be clearly involved with effects on molecular events. To understand how an amyloid may be toxic, we previously generated a yeast toxic amyloid (mutant 8) from the nontoxic HET-s((218-289)) prion domain of Podospora anserina. Here, we performed a comprehensive structure-toxicity study by mutating individually each of the 10 mutations found in mutant 8. The study of the library of new mutants generated allowed us to establish a clear link between Fourier transform infrared antiparallel signature and amyloid toxicity. All of the mutants that form parallel β-sheets are not toxic. Double mutations may be sufficient to shift a parallel structure to antiparallel amyloids, which are toxic to yeast. Our findings also suggest that the toxicity of antiparallel structured mutants may be linked to interaction with membranes.
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Affiliation(s)
- Karine Berthelot
- Institut de Biochimie et Génétique Cellulaires, CNRS UMR 5095, Université Bordeaux 2 «Victor Segalen», 1 rue Camille Saint Saëns, 33077 Bordeaux, France
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21
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Ta HP, Berthelot K, Coulary-Salin B, Desbat B, Géan J, Servant L, Cullin C, Lecomte S. Comparative studies of nontoxic and toxic amyloids interacting with membrane models at the air-water interface. Langmuir 2011; 27:4797-4807. [PMID: 21405042 DOI: 10.1021/la103788r] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Many in vitro studies have pointed out the interaction between amyloids and membranes, and their potential involvement in amyloid toxicity. In a previous study, we generated a yeast toxic mutant (M8) of the harmless model amyloid protein HET-s((218-289)). In this study, we compared the self-assembling process of the nontoxic wild-type (WT) and toxic (M8) protein at the air-water interface and in interaction with various phospholipid monolayers (DOPE, DOPC, DOPI, DOPS and DOPG). We first demonstrate using ellipsometry measurements and polarization-modulated infrared reflection absorption spectroscopy (PMIRRAS) that the air-water interface promotes and modifies the assembly of WT since an amyloid-like film was instantaneously formed at the interface with an antiparallel β-sheet structuration instead of the parallel β-sheet commonly observed for amyloid fibers generated in solution. The toxic mutant (M8) behaves in a similar manner at the air-water interface or in bulk, with a fast self-assembling and an antiparallel β-sheet organization. The transmission electron microscopy (TEM) images established the fibrillous morphology of the protein films formed at the air-water interface. Second, we demonstrate for the first time that the main driving force between this particular fungus amyloid and membrane interaction is based on electrostatic interactions with negatively charged phospholipids (DOPG, DOPI, DOPS). Interestingly, the toxic mutant (M8) clearly induces perturbations of the negatively charged phospholipid monolayers, leading to a massive surface aggregation, whereas the nontoxic (WT) exhibits a slight effect on the membrane models. This study allows concluding that the toxicity of the M8 mutant could be due to its high propensity to interact with membranes.
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Affiliation(s)
- Ha Phuong Ta
- Chimie et Biologie des Membranes et Nano-objets, Université de Bordeaux-CNRS, 2 rue Robert Escarpit, 33607 Pessac, France
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Debaty G, Berthelot K, Bouvaist H, Fluttaz A, Ageron F, Gay S, Bach V, Durand M, Savary D, Schmidt M, Danel V. Refractory cardiac arrest treated by extracorporeal life support in prehospital setting debaty guillaume. Resuscitation 2010. [DOI: 10.1016/j.resuscitation.2010.09.254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Ageron F, Savary D, Decherf T, Debaty G, Baré S, Berthelot K, Belle L, Perfus J. A better survival is associated with the use of a single dispatch center in out-of-hospital cardiac arrests, results from the cardiac arrest cohort in the Northern French Alps emergency network. Resuscitation 2010. [DOI: 10.1016/j.resuscitation.2010.09.126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Berthelot K, Lecomte S, Géan J, Immel F, Cullin C. A yeast toxic mutant of HET-s((218-289)) prion displays alternative intermediates of amyloidogenesis. Biophys J 2010; 99:1239-46. [PMID: 20713008 DOI: 10.1016/j.bpj.2010.06.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 06/08/2010] [Accepted: 06/09/2010] [Indexed: 10/19/2022] Open
Abstract
Amyloids are thought to be involved in various types of neurodegenerative disorders. Several kinds of intermediates, differing in morphology, size, and toxicity, have been identified in the multistep amyloidogenesis process. However, the mechanisms explaining amyloid toxicity remain unclear. We previously generated a toxic mutant of the nontoxic HET-s((218-289)) amyloid in yeast. Here we report that toxic and nontoxic amyloids differ not only in their structures but also in their assembling process. We used multiple and complementary methods to investigate the intermediates formed by these two amyloids. With the methods used, no intermediates were observed for the nontoxic amyloid; however, under the same experimental conditions, the toxic mutant displayed visible oligomeric and fibrillar intermediates.
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Affiliation(s)
- Karine Berthelot
- Institut de Biochimie et Génétique Cellulaires, Centre National de la Recherche Scientifique, UMR 5095, Université Bordeaux 2 "Victor Segalen", Bordeaux, France.
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Couthouis J, Marchal C, D'Angelo F, Berthelot K, Cullin C. The toxicity of an "artificial" amyloid is related to how it interacts with membranes. Prion 2010; 4:283-91. [PMID: 21057225 DOI: 10.4161/pri.4.4.13126] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Despite intensive research into how amyloid structures can impair cellular viability, the molecular nature of these toxic species and the cellular mechanisms involved are not clearly defined and may differ from one disease to another. We systematically analyzed, in Saccharomyces cerevisiae, genes that increase the toxicity of an amyloid (M8), previously selected in yeast on the sole basis of its cellular toxicity (and consequently qualified as "artificial"). This genomic screening identified the Vps-C HOPS (homotypic vacuole fusion and protein sorting) complex as a key-player in amyloid toxicity. This finding led us to analyze further the phenotype induced by M8 expression. M8-expressing cells displayed an identical phenotype to vps mutants in terms of endocytosis, vacuolar morphology and salt sensitivity. The direct and specific interaction between M8 and lipids reinforces the role of membrane formation in toxicity due to M8. Together these findings suggest a model in which amyloid toxicity results from membrane fission.
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Affiliation(s)
- Julien Couthouis
- IBGC, UMR 5095, CNRS, Université Bordeaux 2 Victor Segalen, Bordeaux, France
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Couthouis J, Rébora K, Immel F, Berthelot K, Castroviejo M, Cullin C. Screening for toxic amyloid in yeast exemplifies the role of alternative pathway responsible for cytotoxicity. PLoS One 2009; 4:e4539. [PMID: 19262694 PMCID: PMC2650408 DOI: 10.1371/journal.pone.0004539] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2008] [Accepted: 02/02/2009] [Indexed: 11/24/2022] Open
Abstract
The relationship between amyloid and toxic species is a central problem since the discovery of amyloid structures in different diseases. Despite intensive efforts in the field, the deleterious species remains unknown at the molecular level. This may reflect the lack of any structure-toxicity study based on a genetic approach. Here we show that a structure-toxicity study without any biochemical prerequisite can be successfully achieved in yeast. A PCR mutagenesis of the amyloid domain of HET-s leads to the identification of a mutant that might impair cellular viability. Cellular and biochemical analyses demonstrate that this toxic mutant forms GFP-amyloid aggregates that differ from the wild-type aggregates in their shape, size and molecular organization. The chaperone Hsp104 that helps to disassemble protein aggregates is strictly required for the cellular toxicity. Our structure-toxicity study suggests that the smallest aggregates are the most toxic, and opens a new way to analyze the relationship between structure and toxicity of amyloid species.
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Affiliation(s)
- Julien Couthouis
- IBGC, UMR 5095, CNRS Université Bordeaux 2 “Victor Segalen”, Bordeaux, France
| | - Karine Rébora
- IBGC, UMR 5095, CNRS Université Bordeaux 2 “Victor Segalen”, Bordeaux, France
| | - Françoise Immel
- IBGC, UMR 5095, CNRS Université Bordeaux 2 “Victor Segalen”, Bordeaux, France
| | - Karine Berthelot
- IBGC, UMR 5095, CNRS Université Bordeaux 2 “Victor Segalen”, Bordeaux, France
| | - Michel Castroviejo
- REGER, UMR 5097 CNRS Université Bordeaux 2 “Victor Segalen”, Bordeaux, France
| | - Christophe Cullin
- IBGC, UMR 5095, CNRS Université Bordeaux 2 “Victor Segalen”, Bordeaux, France
- * E-mail:
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Berthelot K, Immel F, Géan J, Lecomte S, Oda R, Kauffmann B, Cullin C. Driving amyloid toxicity in a yeast model by structural changes: a molecular approach. FASEB J 2009; 23:2254-63. [DOI: 10.1096/fj.08-125724] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Karine Berthelot
- Institut de Biochimie et Génétique CellulairesUniversité Bordeaux 2 “Victor Segalen”BordeauxFrance
| | - Franşoise Immel
- Institut de Biochimie et Génétique CellulairesUniversité Bordeaux 2 “Victor Segalen”BordeauxFrance
| | - Julie Géan
- Chimie et Biochimie des Membranes et Nano‐objetsUniversité Bordeaux 1PessacFrance
| | - Sophie Lecomte
- Chimie et Biochimie des Membranes et Nano‐objetsUniversité Bordeaux 1PessacFrance
| | - Reiko Oda
- Chimie et Biochimie des Membranes et Nano‐objetsUniversité Bordeaux 1PessacFrance
| | - Brice Kauffmann
- Chimie et Biochimie des Membranes et Nano‐objetsUniversité Bordeaux 1PessacFrance
| | - Christophe Cullin
- Institut de Biochimie et Génétique CellulairesUniversité Bordeaux 2 “Victor Segalen”BordeauxFrance
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Debaty G, Berthelot K, Savary D, Monnet MF, Bare S, Wurtz S. Is the outcome of pediatric cardiac arrest really worse than adult in the prehospital setting? Resuscitation 2008. [DOI: 10.1016/j.resuscitation.2008.03.203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
The eukaryotic 40S ribosomal subunit locates the translation initiation codon on an mRNA via the so-called scanning process that follows 40S binding to the capped 5' end. This key step in translation is required for the expression of almost all eukaryotic genes, yet the mechanism and dynamics of scanning are unknown. We have performed quantitative studies in vivo and in vitro of the movement of yeast 40S ribosomes along 5' untranslated regions (UTRs) of different lengths. 40S subunits perform cap-dependent scanning with high processivity for more than 1700 nucleotides in cells of Saccharomyces cerevisiae. Moreover, the observed rates of expression indicate that scanning is performed by an untethered 40S subunit that has been released from the 5' cap complex. Unexpectedly, the capability to maintain scanning competence on a long 5' UTR is more dependent on the Ded1/Dbp1 type of helicase than on eIF4A or eIF4B. In a yeast cell-free extract, scanning shows reduced processivity, with an estimated net 5'-->3' rate of approximately 10 nucleotides per second at 26 degrees C. We have developed a biased bidirectional walking model of ribosomal scanning that provides a framework for understanding the above observations as well as other known quantitative and qualitative features of this process.
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Rajkowitsch L, Vilela C, Berthelot K, Ramirez CV, McCarthy JEG. Reinitiation and Recycling are Distinct Processes Occurring Downstream of Translation Termination in Yeast. J Mol Biol 2004; 335:71-85. [PMID: 14659741 DOI: 10.1016/j.jmb.2003.10.049] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The circularisation model of the polysome suggests that ribosome recycling is facilitated by 5'-3' interactions mediated by the cap-binding complex eIF4F and the poly(A)-binding protein, Pab1. Alternatively, downstream of a short upstream open reading frame (uORF) in the 5' untranslated region of a gene, posttermination ribosomes can maintain the competence to (re)initiate translation. Our data show that recycling and reinitiation must be distinct processes in Saccharomyces cerevisiae. The role of the 3'UTR in recycling was assessed by restricting ribosome movement along the mRNA using a poly(G) stretch or the mammalian iron regulatory protein bound to the iron responsive element. We find that although 3'UTR structure can influence translation, the main pathway of ribosome recycling does not depend on scanning-like movement through the 3'UTR. Changes in termination kinetics or disruption of the Pab1-eIF4F interaction do not affect recycling, yet the maintenance of normal in vivo mRNP structure is important to this process. Using bicistronic ACT1-LUC constructs, elongating yeast ribosomes were found to maintain the competence to (re)initiate over only short distances. Thus, as the first ORF to be translated is progressively truncated, reinitiation downstream of an uORF of 105nt is found to be just detectable, and increases markedly in efficiency as uORF length is reduced to 15nt. Experiments using a strain mutated in the Cca1 nucleotidyltransferase suggest that the uORF length-dependence of changes in reinitiation competence is affected by peptide elongation kinetics, but that ORF length per se may also be relevant.
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Affiliation(s)
- Lukas Rajkowitsch
- Posttranscriptional Control Group, Department of Biomolecular Sciences, UMIST, P.O. Box 88, M60 1QD, Manchester, UK
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Abstract
We describe post-transcriptional gene regulation in yeast based on direct RNA-ligand interaction. Tetracycline-dependent translational regulation could be imposed via specific aptamers inserted at two different positions in the 5' untranslated region (5'UTR). Translation in vivo was suppressed up to ninefold upon addition of tetracycline. Repression via an aptamer located near the start codon (cap-distal) in the 5'UTR was more effective than repression via a cap-proximal position. On the other hand, suppression in a cell-free system reached maximally 50-fold and was most effective via a cap-proximal aptamer. Examination of the kinetics of tetracycline-dependent translational inhibition in vitro revealed that preincubation of tetracycline and mRNA before starting translation led not only to the fastest onset of inhibition but also the most effective repression. The differences between the behaviour of the regulatory system in vivo and in vitro are likely to be related to distinct properties of mRNP structure and mRNA accessibility in intact cells as opposed to cell-extracts. Tetracycline-dependent regulation was also observed after insertion of an uORF sequence upstream of the aptamer, indicating that our system also targets reinitiating ribosomes. Polysomal gradient analyses provided insight into the mechanism of regulation. Cap-proximal insertion inhibits binding of the 43S complex to the cap structure whereas start-codon-proximal aptamers interfere with formation of the 80S ribosome, probably by blocking the scanning preinitiation complex.
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Affiliation(s)
- Shane Hanson
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Staudtstrasse 5, 91058 Erlangen, Germany
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Salehi Z, Geffers L, Vilela C, Birkenhäger R, Ptushkina M, Berthelot K, Ferro M, Gaskell S, Hagan I, Stapley B, McCarthy JEG. A nuclear protein in Schizosaccharomyces pombe with homology to the human tumour suppressor Fhit has decapping activity. Mol Microbiol 2002; 46:49-62. [PMID: 12366830 DOI: 10.1046/j.1365-2958.2002.03151.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A number of eukaryotic proteins are already known to orchestrate key steps of mRNA metabolism and translation via interactions with the 5' m7GpppN cap. We have characterized a new type of histidine triad (HIT) motif protein (Nhm1) that co-purifies with the cap-binding complex eIF4F of Schizosaccharomyces pombe. Nhm1 is an RNA-binding protein that binds to m7GTP-Sepharose, albeit with lower specificity and affinity for methylated GTP than is typical for the cap-binding protein known as eukaryotic initiation factor 4E. Sequence searches have revealed that proteins with strong sequence similarity over all regions of the new protein exist in a wide range of eukaryotes, yet none has been characterized up to now. However, other proteins that share specific motifs with Nhm1 include the human Fhit tumour suppressor protein and the diadenosine 5', 5"'-P1, P4-tetraphosphate asymmetrical hydrolase of S. pombe. Our experimental work also reveals that Nhm1 inhibits translation in a cell-free extract prepared from S. pombe, and that it is therefore a putative translational modulator. On the other hand, purified Nhm1 manifests mRNA decapping activity, yet is physically distinct from the Saccharomyces cerevisiae decapping enzyme Dcp1. Moreover, fluorescence and immunofluorescence microscopy show that Nhm1 is predominantly, although not exclusively, nuclear. We conclude that Nhm1 has evolved as a special branch of the HIT motif superfamily that has the potential to influence both the metabolism and the translation of mRNA, and that its presence in S. pombe suggests the utilization of a novel decapping pathway.
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Affiliation(s)
- Zivar Salehi
- Department of Biomolecular Sciences, UMIST, PO Box 88, Manchester M60 1QD, UK
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Abstract
Decapping by Dcp1 in Saccharomyces cerevisiae is a key step in mRNA degradation. However, the cap also binds the eukaryotic initiation factor (eIF) complex 4F and its associated proteins. Characterisation of the relationship between decapping and interactions involving eIF4F is an essential step towards understanding polysome disassembly and mRNA decay. Three types of observation suggest how changes in the functional status of eIF4F modulate mRNA stability in vivo. First, partial disruption of the interaction between eIF4E and eIF4G, caused by mutations in eIF4E or the presence of the yeast 4E-binding protein p20, stabilised mRNAs. The interactions of eIF4G and p20 with eIF4E may therefore act to modulate the decapping process. Since we also show that the in vitro decapping rate is not directly affected by the nature of the body of the mRNA, this suggests that changes in eIF4F structure could play a role in triggering decapping during mRNA decay. Second, these effects were seen in the absence of extreme changes in global translation rates in the cell, and are therefore relevant to normal mRNA turnover. Third, a truncated form of eIF4E (Delta196) had a reduced capacity to inhibit Dcp1-mediated decapping in vitro, yet did not change cellular mRNA half-lives. Thus, the accessibility of the cap to Dcp1 in vivo is not simply controlled by competition with eIF4E, but is subject to switching between molecular states with different levels of access.
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Affiliation(s)
- Carmen Velasco Ramirez
- Posttranscriptional Control Group, Department of Biomolecular Sciences, University of Manchester Institute of Science and Technology (UMIST), P.O. Box 88, M60 1QD, UK
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Ptushkina M, Berthelot K, von der Haar T, Geffers L, Warwicker J, McCarthy JE. A second eIF4E protein in Schizosaccharomyces pombe has distinct eIF4G-binding properties. Nucleic Acids Res 2001; 29:4561-9. [PMID: 11713305 PMCID: PMC92561 DOI: 10.1093/nar/29.22.4561] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The eukaryotic cap-binding proteins belonging to the eIF4E family are generally involved in mediating the recruitment of ribosomes to capped mRNA. We described previously a cap-binding protein (now called eIF4E1) in Schizosaccharomyces pombe that appears to have all of the usual structural and functional attributes of an eIF4E. We have now characterised a new type of cap-binding protein (eIF4E2) from this organism, which at the amino acid sequence level, is 52% identical and 59% similar to eIF4E1. eIF4E2 is not essential in S.pombe but has some novel properties that may be related to a special function in the cell. The ratio of eIF4E2:eIF4E1 in the cell shifts in favour of eIF4E2 at higher temperatures. Despite having all of the dorsal face amino acids that have so far been associated with eIF4G binding to eIF4E1, eIF4E2 binds the eIF4E-binding domain of S.pombe eIF4G >10(2)-times weaker than eIF4E1 in vitro. The eIF4E2 cap-binding affinity is in the typical micromolar range. The results suggest that eIF4E2 is not active on the main pathway of translation initiation in fission yeast but might play a role in the adaptation strategy of this organism under specific growth conditions. Moreover, they provide insight into the molecular characteristics required for tight binding to eIF4G.
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Affiliation(s)
- M Ptushkina
- Posttranscriptional Control Group, Department of Biomolecular Sciences, University of Manchester Institute of Science and Technology, Manchester M60 1QD, UK
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Berthelot K, Delmotte FM. Purification and characterization of an alpha-glucosidase from Rhizobium sp. (Robinia pseudoacacia L.) strain USDA 4280. Appl Environ Microbiol 1999; 65:2907-11. [PMID: 10388682 PMCID: PMC91435 DOI: 10.1128/aem.65.7.2907-2911.1999] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel alpha-glucosidase with an apparent subunit mass of 59 +/- 0. 5 kDa was purified from protein extracts of Rhizobium sp. strain USDA 4280, a nodulating strain of black locust (Robinia pseudoacacia L), and characterized. After purification to homogeneity (475-fold; yield, 18%) by ammonium sulfate precipitation, cation-exchange chromatography, hydrophobic chromatography, dye chromatography, and gel filtration, this enzyme had a pI of 4.75 +/- 0.05. The enzyme activity was optimal at pH 6.0 to 6.5 and 35 degrees C. The activity increased in the presence of NH4+ and K+ ions but was inhibited by Cu2+, Ag+, Hg+, and Fe2+ ions and by various phenyl, phenol, and flavonoid derivatives. Native enzyme activity was revealed by native gel electrophoresis and isoelectrofocusing-polyacrylamide gel electrophoresis with fluorescence detection in which 4-methylumbelliferyl alpha-glucoside was the fluorogenic substrate. The enzyme was more active with alpha-glucosides substituted with aromatic aglycones than with oligosaccharides. This alpha-glucosidase exhibited Michaelis-Menten kinetics with 4-methylumbelliferyl alpha-D-glucopyranoside (Km, 0.141 microM; Vmax, 6.79 micromol min-1 mg-1) and with p-nitrophenyl alpha-D-glucopyranoside (Km, 0.037 microM; Vmax, 2.92 micromol min-1 mg-1). Maltose, trehalose, and sucrose were also hydrolyzed by this enzyme.
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Affiliation(s)
- K Berthelot
- Glycobiologie, Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique UPR 4301, Université d'Orléans, 45071 Orléans cedex 2, France
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Abstract
Interdisciplinary collaboration in home healthcare practice can help to generate successful outcomes for patients. However, effective collaboration requires that disciplines have a thorough understanding of team members' respective roles, use their team members' expertise effectively, and have a willingness to work together to solve problems and integrate interventions. In this case study, nursing and occupational therapy collaborated to maximize one patient's independence in medication administration.
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Affiliation(s)
- B M Touchard
- Department of Occupational Therapy, School of Allied Health, Louisiana State University Medical Center, New Orleans 70112, USA
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Berthelot K, Buret D, Guerin B, Delay D, Negrel J, Delmotte FM. vir-Gene-inducing activities of hydroxycinnamic acid amides in Agrobacterium tumefaciens. Phytochemistry 1998; 49:1537-1548. [PMID: 11711062 DOI: 10.1016/s0031-9422(98)00209-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Expression of Agrobacterium tumefaciens virulence genes and transformation of dicots by this organism are dependent upon host plant phenolic compounds. Several alkylsyringamides have recently been shown to be powerful inducers of these vir-genes. These synthetic amides, and especially ethylsyringamide, are much stronger inducers than syringic acid. In this work, four alkylamides derived from ferulic or sinapic acids were synthesized by a dicyclohexylcarbodiimide method and tested for their potential to induce vir-gene expression on A. tumefaciens strains harbouring virB::lacZ or virE::lacZ fusion plasmids. Their effectiveness was compared to that of ethylsyringamide and tyraminylferulamide, a naturally occurring amide in plants. Whatever the amine moiety of the amide (ethylamine, propylamine, tyramine or beta-alanine ethyl ester) conjugation of the acid functional group clearly diminished the toxicity to the bacteria of the respective acid at high concentration and thereby increased the vir-inducing potential. However, none of the inducers tested exhibited higher activity than acetosyringone, the reference compound for vir-gene induction, with the exception of ethylsyringamide at concentrations above 1mM. When tested on Agrobacterium tumefaciens strain A348(pSM243cd), ethylferulamide and ethylsinapamide were more efficient than the corresponding phenolic acids but only above 100 microM.
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Affiliation(s)
- K Berthelot
- Glycobiologie, Centre de Biophysique Moléculaire, CNRS UPR 4301, affiliated to the University of Orléans, rue Charles Sadron, 45071 cedex 2, Orleans, France
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Steg PG, Tahlil O, Aubailly N, Caillaud JM, Dedieu JF, Berthelot K, Le Roux A, Feldman L, Perricaudet M, Denèfle P, Branellec D. Reduction of restenosis after angioplasty in an atheromatous rabbit model by suicide gene therapy. Circulation 1997; 96:408-11. [PMID: 9244204 DOI: 10.1161/01.cir.96.2.408] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Gene delivery of the thymidine kinase (tk) gene combined with ganciclovir (GCV) limits intimal hyperplasia after abrasion of normal arteries. However, the low efficiency of adenoviral-mediated gene transfer to atherosclerotic arteries has raised concerns about the applicability of this strategy to the prevention of restenosis. METHODS AND RESULTS A replication-defective adenoviral vector expressing tk (Ad-RSVtk) demonstrated selective toxicity toward GCV-treated arterial smooth muscle cells, with oligonucleolytic cleavage suggesting apoptosis. In vivo, after demonstration of tk expression after Ad-RSVtk delivery, the combination of Ad-RSVtk followed by GCV was tested in a rabbit model of angioplasty of atheromatous iliac arteries. Angioplasty (8 atm, 20 minutes) was performed by use of a hydrogel balloon coated with Ad-RSVtk (4x10(9) plaque forming units). GCV was infused (25 mg.kg(-1) I.V. BID) from days 2 through 7 after angioplasty in 8 of 12 rabbits. Four weeks later, morphometric analysis demonstrated a reduced intima-to-media ratio in the group receiving combination therapy compared with Ad-RSVtk alone (3.0+/-1.2 versus 5.2+/-0.5, P<.018). GCV per se had no effect on intimal hyperplasia after arterial injury. CONCLUSIONS In vitro, Ad-RSVtk demonstrates selective toxicity toward GCV-treated arterial smooth muscle cells involving apoptosis. In vivo, GCV conditions reduction of neointimal formation after percutaneous delivery of Ad-RSVtk during angioplasty of atheromatous arteries.
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Affiliation(s)
- P G Steg
- INSERM U-460, Faculté Xavier Bichat, Paris, France
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Abstract
The virulence genes of Agrobacterium tumefaciens are specifically activated by plant phenolic compounds and allow this organism to genetically transform plant cells. New types of phenolic compounds, three phenol amides derived from syringic acid, were synthesized. Introduction of an amide group in syringic acid strongly enhances its vir gene inducing activity.
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Affiliation(s)
- F Dyé
- Centre de Biophysique Moléculaire, CNRS, Orléans, France
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Berthou L, Staels B, Saldicco I, Berthelot K, Casey J, Fruchart JC, Denèfle P, Branellec D. Opposite in vitro and in vivo regulation of hepatic apolipoprotein A-I gene expression by retinoic acid. Absence of effects on apolipoprotein A-II gene expression. Arterioscler Thromb 1994; 14:1657-64. [PMID: 7918317 DOI: 10.1161/01.atv.14.10.1657] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We studied the pharmacological potential of retinoids to modulate apolipoprotein (apo) A-I and apoA-II gene expression and production in vitro in the human cell line HepG2 as well as in primary cultures of adult rat hepatocytes and in vivo in the rat. In HepG2 cells, addition of all-trans retinoic acid (RA) doubled apoA-I mRNA within 24 hours and protein secreted in the culture medium after 48 hours. The induction of apoA-I mRNA by RA was completely blocked by actinomycin D, suggesting that RA acts at the transcriptional level in HepG2 cells. In primary cultures of rat hepatocytes, addition of RA increased apoA-I mRNA in a dose- and time-dependent manner as well as the secretion of apoA-I protein. Similar changes in apoA-I mRNA were observed with 9-cis RA. However, in vivo, hepatic apoA-I mRNA levels decreased after a single administration of RA at 10 mg/kg and remained low after prolonged treatment or at a higher dose, and serum apoA-I concentrations did not change. Furthermore, RA treatment did not substantially affect apoA-II mRNA levels or protein secretion either in vitro or in vivo. As a control, RA receptor-beta mRNA levels increased after RA both in vitro and in vivo. In conclusion, RA treatment selectively induces apoA-I and not apoA-II expression in vitro but not in vivo. These results therefore show additional regulatory effects of RA on apoA-I gene expression in vivo and raise questions about the usefulness of RA in the treatment of atherosclerosis.
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Affiliation(s)
- L Berthou
- Department of Biotechnology C.R.V.A. Rhône-Poulenc Rorer SA, Vitry sur Seine, France
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