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Henry M, Khemiri I, Tebbji F, Abu-Helu R, Vincent AT, Sellam A. Manganese homeostasis modulates fungal virulence and stress tolerance in Candida albicans. mSphere 2024; 9:e0080423. [PMID: 38380913 PMCID: PMC10964418 DOI: 10.1128/msphere.00804-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 01/31/2024] [Indexed: 02/22/2024] Open
Abstract
Due to the scarcity of transition metals within the human host, fungal pathogens have evolved sophisticated mechanisms to uptake and utilize these micronutrients at the infection interface. While considerable attention was turned to iron and copper acquisition mechanisms and their importance in fungal fitness, less was done regarding either the role of manganese (Mn) in infectious processes or the cellular mechanism by which fungal cells achieve their Mn-homeostasis. Here, we undertook transcriptional profiling in the pathogenic fungus Candida albicans experiencing both Mn starvation and excess to capture biological processes that are modulated by this metal. We uncovered that Mn scarcity influences diverse processes associated with fungal fitness including invasion of host cells and antifungal sensitivity. We show that Mn levels influence the abundance of iron and zinc emphasizing the complex crosstalk between metals. The deletion of SMF12, a member of Mn Nramp transporters, confirmed its contribution to Mn uptake. smf12 was unable to form hyphae and damage host cells and exhibited sensitivity to azoles. We found that the unfolded protein response (UPR), likely activated by decreased glycosylation under Mn limitation, was required to recover growth when cells were shifted from an Mn-starved to an Mn-repleted medium. RNA-seq profiling of cells exposed to Mn excess revealed that UPR was also activated. Furthermore, the UPR signaling axis Ire1-Hac1 was required to bypass Mn toxicity. Collectively, this study underscores the importance of Mn homeostasis in fungal virulence and comprehensively provides a portrait of biological functions that are modulated by Mn in a fungal pathogen. IMPORTANCE Transition metals such as manganese provide considerable functionality across biological systems as they are used as cofactors for many catalytic enzymes. The availability of manganese is very limited inside the human body. Consequently, pathogenic microbes have evolved sophisticated mechanisms to uptake this micronutrient inside the human host to sustain their growth and cause infections. Here, we undertook a comprehensive approach to understand how manganese availability impacts the biology of the prevalent fungal pathogen, Candida albicans. We uncovered that manganese homeostasis in this pathogen modulates different biological processes that are essential for host infection which underscores the value of targeting fungal manganese homeostasis for potential antifungal therapeutics development.
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Affiliation(s)
- Manon Henry
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Inès Khemiri
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Faiza Tebbji
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
| | - Rasmi Abu-Helu
- Department of Medical Laboratory Sciences, Faculty of Health Professions, Al-Quds University, Jerusalem, Palestine
| | - Antony T. Vincent
- Department of Animal Sciences, Université Laval, Quebec City, Québec, Canada
| | - Adnane Sellam
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
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Sellam A, Tourabaly M, Borderie V, Bouheraoua N. Evaluation of the efficacy and safety of pars plana vitrectomy with irido-zonulo-hyaloidotomy for malignant glaucoma. J Fr Ophtalmol 2024; 47:103963. [PMID: 37777420 DOI: 10.1016/j.jfo.2023.03.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/26/2023] [Accepted: 03/04/2023] [Indexed: 10/02/2023]
Abstract
PURPOSE To assess the efficacy and safety of pars plana vitrectomy with irido-zonulo-hyaloidotomy (IZH) for fluid misdirection syndrome (FMS) in pseudophakic eyes. METHODS This was a retrospective case series study of patients treated with pars plana vitrectomy with IZH for FMS between February 2017 and March 2020. Complete success was defined as central anterior chamber (AC) deepening with an intraocular pressure (IOP) of 21mmHg or less (on 2 consecutive visits at least 1 week apart) without topical or systemic glaucoma medications. Qualified success was defined as central AC deepening with an IOP of 21mmHg or less (on 2 consecutive visits at least 1 week apart) with topical or systemic glaucoma medications. RESULTS Twelve eyes of 12 patients with a diagnosis of FMS were included. The mean age of the population was 73.6±15.4 years [39-90] with a majority of women (58.3%). Prior surgeries at the time of FMS diagnosis were trabeculectomy (4 eyes) and non-perforating deep sclerectomy (2 eyes). At presentation, mean IOP was 38.2±9.8mmHg, which decreased to 17.9±7.7mmHg (P<0.0001) at final follow-up (mean follow-up of 4.9±4.3 months). Complete success was achieved in 6 eyes (50%) and qualified success in 10 eyes (83%), with two eyes failing treatment. There was no statistical significant relationship between demographic data and clinical success (P > 0.05). CONCLUSION Pars plana vitrectomy combined with IZH appears to be a safe and effective technique for the treatment of FMS in pseudophakic patients.
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Affiliation(s)
- A Sellam
- Centre hospitalier national d'ophtalmologie des Quinze-Vingts, Inserm-DGOS CIC 1423, IHU ForeSight, 28, rue de Charenton, 75012 Paris, France
| | - M Tourabaly
- Centre hospitalier national d'ophtalmologie des Quinze-Vingts, Inserm-DGOS CIC 1423, IHU ForeSight, 28, rue de Charenton, 75012 Paris, France
| | - V Borderie
- Centre hospitalier national d'ophtalmologie des Quinze-Vingts, Inserm-DGOS CIC 1423, IHU ForeSight, 28, rue de Charenton, 75012 Paris, France; Sorbonne université, Inserm, CNRS, institut de la vision, 17, rue Moreau, 75012 Paris, France
| | - N Bouheraoua
- Centre hospitalier national d'ophtalmologie des Quinze-Vingts, Inserm-DGOS CIC 1423, IHU ForeSight, 28, rue de Charenton, 75012 Paris, France; Sorbonne université, Inserm, CNRS, institut de la vision, 17, rue Moreau, 75012 Paris, France.
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Shrivastava M, Kouyoumdjian GS, Kirbizakis E, Ruiz D, Henry M, Vincent AT, Sellam A, Whiteway M. The Adr1 transcription factor directs regulation of the ergosterol pathway and azole resistance in Candida albicans. mBio 2023; 14:e0180723. [PMID: 37791798 PMCID: PMC10653825 DOI: 10.1128/mbio.01807-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 08/07/2023] [Indexed: 10/05/2023] Open
Abstract
IMPORTANCE Research often relies on well-studied orthologs within related species, with researchers using a well-studied gene or protein to allow prediction of the function of the ortholog. In the opportunistic pathogen Candida albicans, orthologs are usually compared with Saccharomyces cerevisiae, and this approach has been very fruitful. Many transcription factors (TFs) do similar jobs in the two species, but many do not, and typically changes in function are driven not by modifications in the structures of the TFs themselves but in the connections between the transcription factors and their regulated genes. This strategy of changing TF function has been termed transcription factor rewiring. In this study, we specifically looked for rewired transcription factors, or Candida-specific TFs, that might play a role in drug resistance. We investigated 30 transcription factors that were potentially rewired or were specific to the Candida clade. We found that the Adr1 transcription factor conferred resistance to drugs like fluconazole, amphotericin B, and terbinafine when activated. Adr1 is known for fatty acid and glycerol utilization in Saccharomyces, but our study reveals that it has been rewired and is connected to ergosterol biosynthesis in Candida albicans.
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Affiliation(s)
- Manjari Shrivastava
- Department of Biology, Concordia University, Montréal, Quebec, Canada
- Center for research, Montreal Heart Institute, Montréal, Quebec, Canada
- Department of Microbiology, Infectiology and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Quebec, Canada
| | | | | | - Daniel Ruiz
- Department of Biology, Concordia University, Montréal, Quebec, Canada
| | - Manon Henry
- Center for research, Montreal Heart Institute, Montréal, Quebec, Canada
- Department of Microbiology, Infectiology and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Quebec, Canada
| | - Antony T. Vincent
- Department of Animal Sciences, Université Laval, Quebec City, Canada
| | - Adnane Sellam
- Center for research, Montreal Heart Institute, Montréal, Quebec, Canada
- Department of Microbiology, Infectiology and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Quebec, Canada
| | - Malcolm Whiteway
- Department of Biology, Concordia University, Montréal, Quebec, Canada
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Chaillot J, Cook MA, Sellam A. Novel determinants of cell size homeostasis in the opportunistic yeast Candida albicans. Curr Genet 2023; 69:67-75. [PMID: 36449086 DOI: 10.1007/s00294-022-01260-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 12/05/2022]
Abstract
The basis for commitment to cell division in late G1 phase, called Start in yeast, is a critical but still poorly understood aspect of eukaryotic cell proliferation. Most dividing cells accumulate mass and grow to a critical cell size before traversing the cell cycle. This size threshold couples cell growth to division and thereby establishes long-term size homeostasis. At present, mechanisms involved in cell size homeostasis in fungal pathogens are not well described. Our previous survey of the size phenome in Candida albicans focused on 279 unique mutants enriched mainly in kinases and transcription factors (Sellam et al. PLoS Genet 15:e1008052, 2019). To uncover novel size regulators in C. albicans and highlight potential innovation within cell size control in pathogenic fungi, we expanded our genetic survey of cell size to include 1301 strains from the GRACE (Gene Replacement and Conditional Expression) collection. The current investigation uncovered both known and novel biological processes required for cell size homeostasis in C. albicans. We also confirmed the plasticity of the size control network as few C. albicans size genes overlapped with those of the budding yeast Saccharomyces cerevisiae. Many new size genes of C. albicans were associated with biological processes that were not previously linked to cell size control and offer an opportunity for future investigation. Additional work is needed to understand if mitochondrial activity is a critical element of the metric that dictates cell size in C. albicans and whether modulation of the onset of actomyosin ring constriction is an additional size checkpoint.
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Affiliation(s)
- Julien Chaillot
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
- Centre de Recherche Paul Pascal, Unité Mixte de Recherche 5031, Université de Bordeaux, Centre National de la Recherche Scientifique, 33600, Pessac, France
| | - Michael A Cook
- Department of Biochemistry and Biomedical Sciences, David Braley Center for Antibiotic Discovery, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON, Canada
| | - Adnane Sellam
- Montreal Heart Institute, Université de Montréal, Montréal, QC, Canada.
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.
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Cohen R, Rybak A, Ouldali N, Angoulvant F, Béchet S, Gajdos V, Hau I, Sellam A, El Aouane El Ghomari I, Elmerich F, Batard C, Auvrignon A, Grimprel E, Favier M, Jung C, Levy C. From the original SARS-CoV-2 strain to the Omicron variant: predictors of COVID-19 in ambulatory symptomatic children. Infect Dis Now 2022; 52:432-440. [PMID: 36116761 PMCID: PMC9477611 DOI: 10.1016/j.idnow.2022.09.012] [Citation(s) in RCA: 2] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 09/06/2022] [Accepted: 09/12/2022] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To determine the predictors of a positive SARS-CoV-2 test in a pediatric ambulatory setting. PATIENTS AND METHODS We performed a cross-sectional prospective study (November 2020-February 2022) of 93 ambulatory settings in France. We included symptomatic children < 15 years old tested for SARS-CoV-2. For each period corresponding to the spread of the original strain and its variants (period 1: original strain; period 2: Alpha, period 3: Delta; period 4: Omicron), we used a multivariate analysis to estimate adjusted odds ratios (aORs) associated with COVID-19 among age, signs, symptoms or contact, and 95 % confidence intervals (95CIs). RESULTS Of 5,336 children, 13.9 % (95CI 13.0-14.8) had a positive test. During the first three periods, the positivity rate ranged from 5.6 % (95CI 4.6-6.7) to 12.6 % (95CI 10.8-14.6). The main factors associated with a positive test were contact with an infected adult at home or outside the home (aOR 11.5 [95CI 4.9-26.9] to 38.9 [95CI 19.3-78.7]) or an infected household child (aOR 15.0 [95CI 4.8-47.1] to 28.4 [95CI 8.7-92.6]). By contrast, during period 4, aORs for these predictors were substantially lower (2.3 [95CI 1.1-4.5] to 5.5 [95CI 3.2-7.7]), but the positivity rate was 45.7 % (95CI 42.3-49.2). CONCLUSIONS In pediatric ambulatory settings, before the Omicron period, the main predictor of a positive test was contact with an infected person. During the Omicron period, the odds of these predictors were substantially lower while the positivity rate was higher. An accurate diagnostic strategy should only rely on testing and not on age, signs, symptoms or contact.
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Affiliation(s)
- R Cohen
- ACTIV, Association Clinique et Thérapeutique Infantile du Val-de-Marne, Créteil, France; Clinical Research Center (CRC), Centre Hospitalier Intercommunal de Créteil, Créteil, France; Université Paris Est, IMRB-GRC GEMINI, Créteil, France; AFPA, Association Française de Pédiatrie Ambulatoire, Orléans, France; GPIP, Groupe de Pathologie Infectieuse Pédiatrique, Créteil, France
| | - A Rybak
- ACTIV, Association Clinique et Thérapeutique Infantile du Val-de-Marne, Créteil, France; AFPA, Association Française de Pédiatrie Ambulatoire, Orléans, France; Unité d'Épidémiologie Clinique, Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, ECEVE INSERM UMR 1123, Paris, France.
| | - N Ouldali
- ACTIV, Association Clinique et Thérapeutique Infantile du Val-de-Marne, Créteil, France; AFPA, Association Française de Pédiatrie Ambulatoire, Orléans, France; GPIP, Groupe de Pathologie Infectieuse Pédiatrique, Créteil, France; Unité d'Épidémiologie Clinique, Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, ECEVE INSERM UMR 1123, Paris, France; Assistance Publique - Hôpitaux de Paris, Pediatric Department, Robert Debré Hospital, France
| | - F Angoulvant
- GPIP, Groupe de Pathologie Infectieuse Pédiatrique, Créteil, France; Assistance Publique - Hôpitaux de Paris, Pediatric Department, Robert Debré Hospital, France; INSERM, Centre de Recherche des Cordeliers, UMRS 1138, Sorbonne Université, Université de Paris, Paris, France
| | - S Béchet
- ACTIV, Association Clinique et Thérapeutique Infantile du Val-de-Marne, Créteil, France; Clinical Research Center (CRC), Centre Hospitalier Intercommunal de Créteil, Créteil, France
| | - V Gajdos
- GPIP, Groupe de Pathologie Infectieuse Pédiatrique, Créteil, France; Centre for Research in Epidemiology and Population Health, INSERM UMR1018, Villejuif, France; Assistance Publique-Hôpitaux de Paris, Pediatric Department, Antoine Béclère University Hospital, Université de Paris Saclay, Clamart, France
| | - I Hau
- Université Paris Est, IMRB-GRC GEMINI, Créteil, France; GPIP, Groupe de Pathologie Infectieuse Pédiatrique, Créteil, France; Service de pédiatrie, Centre Hospitalier Intercommunal de Créteil, Créteil, France
| | - A Sellam
- ACTIV, Association Clinique et Thérapeutique Infantile du Val-de-Marne, Créteil, France
| | | | - F Elmerich
- CHU Reims, Urgences Pédiatriques, France
| | - C Batard
- ACTIV, Association Clinique et Thérapeutique Infantile du Val-de-Marne, Créteil, France; AFPA, Association Française de Pédiatrie Ambulatoire, Orléans, France
| | - A Auvrignon
- ACTIV, Association Clinique et Thérapeutique Infantile du Val-de-Marne, Créteil, France; AFPA, Association Française de Pédiatrie Ambulatoire, Orléans, France
| | - E Grimprel
- GPIP, Groupe de Pathologie Infectieuse Pédiatrique, Créteil, France; Service de pédiatrie, Hôpital Trousseau, Paris, France
| | - M Favier
- GPIP, Groupe de Pathologie Infectieuse Pédiatrique, Créteil, France; Urgences Pédiatriques CHU de Bordeaux, Bordeaux, France
| | - C Jung
- Clinical Research Center (CRC), Centre Hospitalier Intercommunal de Créteil, Créteil, France; Université Paris Est, IMRB-GRC GEMINI, Créteil, France
| | - C Levy
- ACTIV, Association Clinique et Thérapeutique Infantile du Val-de-Marne, Créteil, France; Clinical Research Center (CRC), Centre Hospitalier Intercommunal de Créteil, Créteil, France; Université Paris Est, IMRB-GRC GEMINI, Créteil, France; AFPA, Association Française de Pédiatrie Ambulatoire, Orléans, France; GPIP, Groupe de Pathologie Infectieuse Pédiatrique, Créteil, France.
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Chaillot J, Mallick J, Sellam A. The transcription factor Ahr1 links cell size control to amino acid metabolism in the opportunistic yeast Candida albicans. Biochem Biophys Res Commun 2022; 616:63-69. [DOI: 10.1016/j.bbrc.2022.05.074] [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] [Received: 04/29/2022] [Accepted: 05/21/2022] [Indexed: 11/17/2022]
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Henry M, Burgain A, Tebbji F, Sellam A. Transcriptional Control of Hypoxic Hyphal Growth in the Fungal Pathogen Candida albicans. Front Cell Infect Microbiol 2022; 11:770478. [PMID: 35127551 PMCID: PMC8807691 DOI: 10.3389/fcimb.2021.770478] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/26/2021] [Indexed: 12/18/2022] Open
Abstract
The ability of Candida albicans, an important human fungal pathogen, to develop filamentous forms is a crucial determinant for host invasion and virulence. While hypoxia is one of the predominant host cues that promote C. albicans filamentous growth, the regulatory circuits that link oxygen availability to filamentation remain poorly characterized. We have undertaken a genetic screen and identified the two transcription factors Ahr1 and Tye7 as central regulators of the hypoxic filamentation. Both ahr1 and tye7 mutants exhibited a hyperfilamentous phenotype specifically under an oxygen-depleted environment suggesting that these transcription factors act as negative regulators of hypoxic filamentation. By combining microarray and ChIP-chip analyses, we have characterized the set of genes that are directly modulated by Ahr1 and Tye7. We found that both Ahr1 and Tye7 modulate a distinct set of genes and biological processes. Our genetic epistasis analysis supports our genomic finding and suggests that Ahr1 and Tye7 act independently to modulate hyphal growth in response to hypoxia. Furthermore, our genetic interaction experiments uncovered that Ahr1 and Tye7 repress the hypoxic filamentation via the Efg1 and Ras1/Cyr1 pathways, respectively. This study yielded a new and an unprecedented insight into the oxygen-sensitive regulatory circuit that control morphogenesis in a fungal pathogen.
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Affiliation(s)
- Manon Henry
- Montreal Heart Institute, Université de Montréal, Montréal, QC, Canada
| | - Anaïs Burgain
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
| | - Faiza Tebbji
- Montreal Heart Institute, Université de Montréal, Montréal, QC, Canada
| | - Adnane Sellam
- Montreal Heart Institute, Université de Montréal, Montréal, QC, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada
- *Correspondence: Adnane Sellam,
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Saad S, Sellam A, Borderie V, Bouheraoua N. [OCT-guided aspiration of subfoveal perfluorocarbon liquid using a 27-gauge cannula]. J Fr Ophtalmol 2021; 44:1076-1078. [PMID: 34243999 DOI: 10.1016/j.jfo.2021.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 01/10/2021] [Indexed: 11/15/2022]
Affiliation(s)
- S Saad
- CHNO des Quinze-Vingts, Inserm-DGOS CIC 1423, IHU ForeSight, 28, rue de Charenton, 75012 Paris, France
| | - A Sellam
- CHNO des Quinze-Vingts, Inserm-DGOS CIC 1423, IHU ForeSight, 28, rue de Charenton, 75012 Paris, France.
| | - V Borderie
- CHNO des Quinze-Vingts, Inserm-DGOS CIC 1423, IHU ForeSight, 28, rue de Charenton, 75012 Paris, France; Sorbonne Université, Inserm, CNRS, Institut de la Vision, 17, rue Moreau, 75012 Paris, France
| | - N Bouheraoua
- CHNO des Quinze-Vingts, Inserm-DGOS CIC 1423, IHU ForeSight, 28, rue de Charenton, 75012 Paris, France; Sorbonne Université, Inserm, CNRS, Institut de la Vision, 17, rue Moreau, 75012 Paris, France
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Hussain N, Delar E, Piochon M, Groleau MC, Tebbji F, Sellam A, Déziel E, Gauthier C. Total synthesis of the proposed structures of gladiosides I and II. Carbohydr Res 2021; 507:108373. [PMID: 34157641 DOI: 10.1016/j.carres.2021.108373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/07/2021] [Accepted: 06/07/2021] [Indexed: 10/21/2022]
Abstract
Burkholderia gladioli is a Gram-negative bacterium that biosynthesizes a cocktail of potent antimicrobial compounds, including the antifungal phenolic glycoside sinapigladioside. Herein, we report the total synthesis of the proposed structures of gladiosides I and II, two structurally related phenolic glycosides previously isolated from B. gladioli OR1 cultures. Importantly, the physical and analytical data of the synthetic compounds were in significant discrepancies with the natural products suggesting a misassignment of the originally proposed structures. Furthermore, we have uncovered an acid-catalyzed fragmentation mechanism converting the α,β-unsaturated methyl carbamate-containing gladioside II into the aldehyde-containing gladioside I. Our results lay the foundation for the expeditious synthesis of derivatives of these Burkholderia-derived phenolic glycosides, which would enable to decipher their biological roles and potential pharmacological properties.
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Affiliation(s)
- Nazar Hussain
- Centre Armand-Frappier Santé Biotechnologie, Institut National de La Recherche Scientifique (INRS), 531 Boulevard des Prairies, Laval (Québec), H7V 1B7, Canada
| | - Emmanilo Delar
- Centre Armand-Frappier Santé Biotechnologie, Institut National de La Recherche Scientifique (INRS), 531 Boulevard des Prairies, Laval (Québec), H7V 1B7, Canada
| | - Marianne Piochon
- Centre Armand-Frappier Santé Biotechnologie, Institut National de La Recherche Scientifique (INRS), 531 Boulevard des Prairies, Laval (Québec), H7V 1B7, Canada
| | - Marie-Christine Groleau
- Centre Armand-Frappier Santé Biotechnologie, Institut National de La Recherche Scientifique (INRS), 531 Boulevard des Prairies, Laval (Québec), H7V 1B7, Canada
| | - Faiza Tebbji
- Department of Microbiology, Infectious Disease and Immunology, Montreal Heart Institute, Université de Montréal, 5000 Rue Bélanger, Montréal (Québec), H1T 1C8, Canada
| | - Adnane Sellam
- Department of Microbiology, Infectious Disease and Immunology, Montreal Heart Institute, Université de Montréal, 5000 Rue Bélanger, Montréal (Québec), H1T 1C8, Canada
| | - Eric Déziel
- Centre Armand-Frappier Santé Biotechnologie, Institut National de La Recherche Scientifique (INRS), 531 Boulevard des Prairies, Laval (Québec), H7V 1B7, Canada
| | - Charles Gauthier
- Centre Armand-Frappier Santé Biotechnologie, Institut National de La Recherche Scientifique (INRS), 531 Boulevard des Prairies, Laval (Québec), H7V 1B7, Canada.
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Villa S, Hamideh M, Weinstock A, Qasim MN, Hazbun TR, Sellam A, Hernday AD, Thangamani S. Transcriptional control of hyphal morphogenesis in Candida albicans. FEMS Yeast Res 2021; 20:5715912. [PMID: 31981355 PMCID: PMC7000152 DOI: 10.1093/femsyr/foaa005] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 01/31/2020] [Indexed: 12/12/2022] Open
Abstract
Candida albicans is a multimorphic commensal organism and opportunistic fungal pathogen in humans. A morphological switch between unicellular budding yeast and multicellular filamentous hyphal growth forms plays a vital role in the virulence of C. albicans, and this transition is regulated in response to a range of environmental cues that are encountered in distinct host niches. Many unique transcription factors contribute to the transcriptional regulatory network that integrates these distinct environmental cues and determines which phenotypic state will be expressed. These hyphal morphogenesis regulators have been extensively investigated, and represent an increasingly important focus of study, due to their central role in controlling a key C. albicans virulence attribute. This review provides a succinct summary of the transcriptional regulatory factors and environmental signals that control hyphal morphogenesis in C. albicans.
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Affiliation(s)
- Sonia Villa
- Masters in Biomedical Science Program, Midwestern University, 19555 N. 59th Ave. Glendale, AZ 85308, USA
| | - Mohammad Hamideh
- Masters in Biomedical Science Program, Midwestern University, 19555 N. 59th Ave. Glendale, AZ 85308, USA
| | - Anthony Weinstock
- Arizona College of Osteopathic Medicine, Midwestern University, 19555 N. 59th Ave. Glendale, AZ 85308, USA
| | - Mohammad N Qasim
- Quantitative and Systems Biology Graduate Program, School of Natural Sciences, University of California, Merced, Merced, CA, 95343, USA
| | - Tony R Hazbun
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA
| | - Adnane Sellam
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
| | - Aaron D Hernday
- Quantitative and Systems Biology Graduate Program, School of Natural Sciences, University of California, Merced, Merced, CA, 95343, USA.,Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, Merced, CA, 95343, USA
| | - Shankar Thangamani
- Department of Pathology and Population Medicine, College of Veterinary Medicine, Midwestern University, 19555 N. 59th Ave. Glendale, AZ 85308, USA
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11
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Horianopoulos LC, Gluck-Thaler E, Benoit Gelber I, Cowen LE, Geddes-McAlister J, Landry CR, Schwartz IS, Scott JA, Sellam A, Sheppard DC, Spribille T, Subramaniam R, Walker AK, Harris SD, Shapiro RS, Gerstein AC. The Canadian Fungal Research Network: current challenges and future opportunities. Can J Microbiol 2020; 67:13-22. [PMID: 32717148 DOI: 10.1139/cjm-2020-0263] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Fungi critically impact the health and function of global ecosystems and economies. In Canada, fungal researchers often work within silos defined by subdiscipline and institutional type, complicating the collaborations necessary to understand the impacts fungi have on the environment, economy, and plant and animal health. Here, we announce the establishment of the Canadian Fungal Research Network (CanFunNet, https://fungalresearch.ca), whose mission is to strengthen and promote fungal research in Canada by facilitating dialogue among scientists. We summarize the challenges and opportunities for Canadian fungal research that were discussed at CanFunNet's inaugural meeting in 2019, and identify 4 priorities for our community: (i) increasing collaboration among scientists, (ii) studying diversity in the context of ecological disturbance, (iii) preserving culture collections in the absence of sustained funding, and (iv) leveraging diverse expertise to attract trainees. We have gathered additional information to support our recommendations, including a survey identifying underrepresentation of fungal-related courses at Canadian universities, a list of Canadian fungaria and culture collections, and a case study of a human fungal pathogen outbreak. We anticipate that these discussions will help prioritize fungal research in Canada, and we welcome all researchers to join this nationwide effort to enhance knowledge dissemination and funding advocacy.
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Affiliation(s)
- Linda C Horianopoulos
- Department of Microbiology and Immunology, University of British Columbia, 2185 East Mall, Vancouver, BC V6T 1Z4, Canada
| | - Emile Gluck-Thaler
- Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Isabelle Benoit Gelber
- Centre for Structural and Functional Genomics, Department of Biology, Concordia University, 7141 Sherbrooke Street West, Montréal, QC H4B 1R6, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, ON M5G 1M1, Canada
| | - Jennifer Geddes-McAlister
- Department of Molecular and Cellular Biology, University of Guelph, 474-570 Gordon Street, Guelph, ON N1G 1Y2, Canada
| | - Christian R Landry
- Département de biologie and Département de biochimie, microbiologie et bio-informatique, Université Laval, 1030, avenue de la Médecine, Québec, QC G1V 0A6, Canada
| | - Ilan S Schwartz
- Division of Infectious Diseases, Department of Medicine, Faculty of Medicine & Dentistry, University of Alberta, 8440 112 Street NW, Edmonton, AB T6G 2R7, Canada
| | - James A Scott
- Dalla Lana School of Public Health, University of Toronto, 223 College Street, Toronto, ON, M5T 1R4, Canada
| | - Adnane Sellam
- Department of Microbiology, Infectious Disease and Immunology, Montreal Heart Institute, Université de Montréal, 5000, rue Bélanger, Montréal, QC H1T 1C8, Canada
| | - Donald C Sheppard
- Department of Microbiology and Immunology, McGill University, 3775, rue University, Room 511, Montréal, QC H3A 2B4.,McGill Interdisciplinary Initiative in Infection and Immunity, 3666 McTavish Street, 2nd Floor, Montréal, QC H3Y 1Y2, Canada
| | - Toby Spribille
- Department of Biological Sciences, University of Alberta, 11335 Saskatchewan Drive NW, Edmonton, AB T6G 2H5, Canada
| | - Rajagopal Subramaniam
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
| | - Allison K Walker
- Department of Biology, Acadia University, 33 Westwood Avenue, Room 302, Wolfville, NS B4P 2R6, Canada
| | - Steven D Harris
- Department of Biological Sciences, University of Manitoba, Biological Sciences Building, Winnipeg, MB R3T 2N2, Canada
| | - Rebecca S Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, 474-570 Gordon Street, Guelph, ON N1G 1Y2, Canada
| | - Aleeza C Gerstein
- Department of Microbiology, University of Manitoba, 213 Buller Building, Winnipeg, MB R3T 2N2, Canada.,Department of Statistics, University of Manitoba, 318 Machray Hall, Winnipeg, MB R3T 2N2, Canada
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12
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Khemiri I, Tebbji F, Sellam A. Transcriptome Analysis Uncovers a Link Between Copper Metabolism, and Both Fungal Fitness and Antifungal Sensitivity in the Opportunistic Yeast Candida albicans. Front Microbiol 2020; 11:935. [PMID: 32508775 PMCID: PMC7248230 DOI: 10.3389/fmicb.2020.00935] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 04/20/2020] [Indexed: 12/16/2022] Open
Abstract
Copper homeostasis is an important determinant for virulence of many human pathogenic fungi such as the highly prevalent yeast Candida albicans. However, beyond the copper transporter Ctr1, little is known regarding other genes and biological processes that are affected by copper. To gain insight into the cellular processes that are modulated by copper abundance in C. albicans, we monitored the global gene expression dynamic under both copper depletion and excess using RNA-seq. Beyond copper metabolism, other different transcriptional programs related to fungal fitness such as stress responses, antifungal sensitivity, host invasion and commensalism were modulated in response to copper variations. We have also investigated the transcriptome of the mutant of the copper utilization regulator, mac1, and identified potential direct targets of this transcription factor under copper starvation. We also showed that Mac1 was required for the invasion and adhesion to host cells and antifungal tolerance. This study provides a framework for future studies to examine the link between copper metabolism and essential functions that modulate fungal virulence and fitness inside the host.
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Affiliation(s)
- Inès Khemiri
- CHU de Québec Research Center, Université Laval, Quebec City, QC, Canada
| | - Faiza Tebbji
- CHU de Québec Research Center, Université Laval, Quebec City, QC, Canada
| | - Adnane Sellam
- CHU de Québec Research Center, Université Laval, Quebec City, QC, Canada.,Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
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13
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Burgain A, Pic É, Markey L, Tebbji F, Kumamoto CA, Sellam A. A novel genetic circuitry governing hypoxic metabolic flexibility, commensalism and virulence in the fungal pathogen Candida albicans. PLoS Pathog 2019; 15:e1007823. [PMID: 31809527 PMCID: PMC6919631 DOI: 10.1371/journal.ppat.1007823] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 12/18/2019] [Accepted: 10/18/2019] [Indexed: 01/04/2023] Open
Abstract
Inside the human host, the pathogenic yeast Candida albicans colonizes predominantly oxygen-poor niches such as the gastrointestinal and vaginal tracts, but also oxygen-rich environments such as cutaneous epithelial cells and oral mucosa. This suppleness requires an effective mechanism to reversibly reprogram the primary metabolism in response to oxygen variation. Here, we have uncovered that Snf5, a subunit of SWI/SNF chromatin remodeling complex, is a major transcriptional regulator that links oxygen status to the metabolic capacity of C. albicans. Snf5 and other subunits of SWI/SNF complex were required to activate genes of carbon utilization and other carbohydrates related process specifically under hypoxia. snf5 mutant exhibited an altered metabolome reflecting that SWI/SNF plays an essential role in maintaining metabolic homeostasis and carbon flux in C. albicans under hypoxia. Snf5 was necessary to activate the transcriptional program linked to both commensal and invasive growth. Accordingly, snf5 was unable to maintain its growth in the stomach, the cecum and the colon of mice. snf5 was also avirulent as it was unable to invade Galleria larvae or to cause damage to human enterocytes and murine macrophages. Among candidates of signaling pathways in which Snf5 might operate, phenotypic analysis revealed that mutants of Ras1-cAMP-PKA pathway, as well as mutants of Yak1 and Yck2 kinases exhibited a similar carbon flexibility phenotype as did snf5 under hypoxia. Genetic interaction analysis indicated that the adenylate cyclase Cyr1, a key component of the Ras1-cAMP pathway interacted genetically with Snf5. Our study yielded new insight into the oxygen-sensitive regulatory circuit that control metabolic flexibility, stress, commensalism and virulence in C. albicans. A critical aspect of eukaryotic cell fitness is the ability to sense and adapt to variations in oxygen level in their local environment. Hypoxia leads to a substantial remodeling of cell metabolism and energy homeostasis, and thus, organisms must develop an effective regulatory mechanism to cope with oxygen depletion. Candida albicans is an opportunistic yeast that is the most prevalent human fungal pathogens. This yeast colonizes diverse niches inside the human host with contrasting carbon sources and oxygen concentrations. While hypoxia is the predominant condition that C. albicans encounters inside most of the niches, the impact of this condition on metabolic flexibility, a major determinant of fungal virulence, was completely unexplored. Here, we uncovered that the chromatin remodelling complex SWI/SNF is a master regulator of the circuit that links oxygen status to a broad spectrum of carbon utilization routes. Snf5 was essential for the maintenance of C. albicans as a commensal and also for the expression of its virulence. The oxygen-sensitive regulators identified in this work provide a framework to comprehensively understand the virulence of human fungal pathogens and represent a therapeutic value to fight fungal infections.
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Affiliation(s)
- Anaïs Burgain
- CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, Quebec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
| | - Émilie Pic
- CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, Quebec, Canada
| | - Laura Markey
- Program in Molecular Microbiology, Tufts University, Boston, Massachusetts, United States of America
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
| | - Faiza Tebbji
- CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, Quebec, Canada
| | - Carol A. Kumamoto
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
| | - Adnane Sellam
- CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, Quebec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
- Big Data Research Centre (BDRC-UL), Université Laval, Faculty of Sciences and Engineering, Quebec City, Quebec, Canada
- * E-mail:
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14
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Pic E, Burgain A, Sellam A. Repurposing the anthelminthic salicylanilide oxyclozanide against susceptible and clinical resistant Candida albicans strains. Med Mycol 2019; 57:387-390. [PMID: 29762783 DOI: 10.1093/mmy/myy027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [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: 12/30/2017] [Revised: 03/14/2018] [Accepted: 04/05/2018] [Indexed: 12/16/2022] Open
Abstract
Current antifungal drugs suffer from limitations including toxicity, adverse interactions with other commonly prescribed drugs, and the emergence of resistant strains. Here, we repurposed the anthelmintic oxyclozanide as a potent antifungal agent against both sensitive and resistant clinical isolates of Candida albicans, as well as other human opportunistic fungi. Antifungal activity of oxyclozanide was enhanced when C. albicans grew in nonfermentable carbon sources. Our data support a mechanism of action where oxyclozanide uncoupled the mitochondrial electron transport from oxidative phosphorylation and perturbed the mitochondrial membrane potential.
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Affiliation(s)
- Emilie Pic
- Infectious Diseases Research Centre-CRI, CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
| | - Anaïs Burgain
- Infectious Diseases Research Centre-CRI, CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
| | - Adnane Sellam
- Infectious Diseases Research Centre-CRI, CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada.,Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
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15
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Sellam A, Chaillot J, Mallick J, Tebbji F, Richard Albert J, Cook MA, Tyers M. The p38/HOG stress-activated protein kinase network couples growth to division in Candida albicans. PLoS Genet 2019; 15:e1008052. [PMID: 30921326 PMCID: PMC6456229 DOI: 10.1371/journal.pgen.1008052] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 04/09/2019] [Accepted: 02/28/2019] [Indexed: 12/26/2022] Open
Abstract
Cell size is a complex trait that responds to developmental and environmental cues. Quantitative size analysis of mutant strain collections disrupted for protein kinases and transcriptional regulators in the pathogenic yeast Candida albicans uncovered 66 genes that altered cell size, few of which overlapped with known size genes in the budding yeast Saccharomyces cerevisiae. A potent size regulator specific to C. albicans was the conserved p38/HOG MAPK module that mediates the osmostress response. Basal HOG activity inhibited the SBF G1/S transcription factor complex in a stress-independent fashion to delay the G1/S transition. The HOG network also governed ribosome biogenesis through the master transcriptional regulator Sfp1. Hog1 bound to the promoters and cognate transcription factors for ribosome biogenesis regulons and interacted genetically with the SBF G1/S machinery, and thereby directly linked cell growth and division. These results illuminate the evolutionary plasticity of size control and identify the HOG module as a nexus of cell cycle and growth regulation.
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Affiliation(s)
- Adnane Sellam
- Infectious Diseases Research Centre (CRI), CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
- Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
| | - Julien Chaillot
- Infectious Diseases Research Centre (CRI), CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
| | - Jaideep Mallick
- Institute for Research in Immunology and Cancer (IRIC), Department of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Faiza Tebbji
- Infectious Diseases Research Centre (CRI), CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
| | - Julien Richard Albert
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael A. Cook
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Mike Tyers
- Institute for Research in Immunology and Cancer (IRIC), Department of Medicine, Université de Montréal, Montréal, Québec, Canada
- Centre for Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
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16
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Polvi EJ, Veri AO, Liu Z, Hossain S, Hyde S, Kim SH, Tebbji F, Sellam A, Todd RT, Xie JL, Lin ZY, Wong CJ, Shapiro RS, Whiteway M, Robbins N, Gingras AC, Selmecki A, Cowen LE. Functional divergence of a global regulatory complex governing fungal filamentation. PLoS Genet 2019; 15:e1007901. [PMID: 30615616 PMCID: PMC6336345 DOI: 10.1371/journal.pgen.1007901] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 01/17/2019] [Accepted: 12/16/2018] [Indexed: 01/17/2023] Open
Abstract
Morphogenetic transitions are prevalent in the fungal kingdom. For a leading human fungal pathogen, Candida albicans, the capacity to transition between yeast and filaments is key for virulence. For the model yeast Saccharomyces cerevisiae, filamentation enables nutrient acquisition. A recent functional genomic screen in S. cerevisiae identified Mfg1 as a regulator of morphogenesis that acts in complex with Flo8 and Mss11 to mediate transcriptional responses crucial for filamentation. In C. albicans, Mfg1 also interacts physically with Flo8 and Mss11 and is critical for filamentation in response to diverse cues, but the mechanisms through which it regulates morphogenesis remained elusive. Here, we explored the consequences of perturbation of Mfg1, Flo8, and Mss11 on C. albicans morphogenesis, and identified functional divergence of complex members. We observed that C. albicans Mss11 was dispensable for filamentation, and that overexpression of FLO8 caused constitutive filamentation even in the absence of Mfg1. Harnessing transcriptional profiling and chromatin immunoprecipitation coupled to microarray analysis, we identified divergence between transcriptional targets of Flo8 and Mfg1 in C. albicans. We also established that Flo8 and Mfg1 cooperatively bind to promoters of key regulators of filamentation, including TEC1, for which overexpression was sufficient to restore filamentation in the absence of Flo8 or Mfg1. To further explore the circuitry through which Mfg1 regulates morphogenesis, we employed a novel strategy to select for mutations that restore filamentation in the absence of Mfg1. Whole genome sequencing of filamentation-competent mutants revealed chromosome 6 amplification as a conserved adaptive mechanism. A key determinant of the chromosome 6 amplification is FLO8, as deletion of one allele blocked morphogenesis, and chromosome 6 was not amplified in evolved lineages for which FLO8 was re-located to a different chromosome. Thus, this work highlights rewiring of key morphogenetic regulators over evolutionary time and aneuploidy as an adaptive mechanism driving fungal morphogenesis. Fungal infections pose a severe burden to human health worldwide. Candida albicans is a leading cause of systemic fungal infections, with mortality rates approaching 40%. One of the key virulence traits of this fungus is its ability to transition between yeast and filamentous forms in response to diverse host-relevant cues. The model yeast Saccharomyces cerevisiae is also capable of filamentous growth in certain conditions, and previous work has identified a key transcriptional complex required for filamentation in both species. However, here we discover that the circuitry governed by this complex in C. albicans is largely distinct from that in the non-pathogenic S. cerevisiae. We also employ a novel selection strategy to perform experimental evolution, identifying chromosome triplication as a mechanism to restore filamentation in a non-filamentous mutant. This work reveals unique circuitry governing a key virulence trait in a leading fungal pathogen, identifying potential therapeutic targets to combat these life-threatening infections.
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Affiliation(s)
- Elizabeth J. Polvi
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Amanda O. Veri
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Zhongle Liu
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Saif Hossain
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Sabrina Hyde
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Sang Hu Kim
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Faiza Tebbji
- Infectious Disease Research Centre, Université Laval, Quebec, Canada
| | - Adnane Sellam
- Infectious Disease Research Centre, Université Laval, Quebec, Canada
| | - Robert T. Todd
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Jinglin L. Xie
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Zhen-Yuan Lin
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Ontario, Canada
| | - Cassandra J. Wong
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Ontario, Canada
| | - Rebecca S. Shapiro
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | | | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Anne-Claude Gingras
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Ontario, Canada
| | - Anna Selmecki
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, United States of America
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Ontario, Canada
- * E-mail:
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17
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Garcia C, Burgain A, Chaillot J, Pic É, Khemiri I, Sellam A. A phenotypic small-molecule screen identifies halogenated salicylanilides as inhibitors of fungal morphogenesis, biofilm formation and host cell invasion. Sci Rep 2018; 8:11559. [PMID: 30068935 PMCID: PMC6070544 DOI: 10.1038/s41598-018-29973-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/23/2018] [Indexed: 12/15/2022] Open
Abstract
A poorly exploited paradigm in the antimicrobial therapy field is to target virulence traits for drug development. In contrast to target-focused approaches, antivirulence phenotypic screens enable identification of bioactive molecules that induce a desirable biological readout without making a priori assumption about the cellular target. Here, we screened a chemical library of 678 small molecules against the invasive hyphal growth of the human opportunistic yeast Candida albicans. We found that a halogenated salicylanilide (N1-(3,5-dichlorophenyl)-5-chloro-2-hydroxybenzamide) and one of its analogs, Niclosamide, an FDA-approved anthelmintic in humans, exhibited both antifilamentation and antibiofilm activities against C. albicans and the multi-resistant yeast C. auris. The antivirulence activity of halogenated salicylanilides were also expanded to C. albicans resistant strains with different resistance mechanisms. We also found that Niclosamide protected the intestinal epithelial cells against invasion by C. albicans. Transcriptional profiling of C. albicans challenged with Niclosamide exhibited a signature that is characteristic of the mitochondria-to-nucleus retrograde response. Our chemogenomic analysis showed that halogenated salicylanilides compromise the potential-dependant mitochondrial protein translocon machinery. Given the fact that the safety of Niclosamide is well established in humans, this molecule could represent the first clinically approved antivirulence agent against a pathogenic fungus.
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Affiliation(s)
- Carlos Garcia
- CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
| | - Anaïs Burgain
- CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
| | - Julien Chaillot
- CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
| | - Émilie Pic
- CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
| | - Inès Khemiri
- CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada
| | - Adnane Sellam
- CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, QC, Canada.
- Department of Microbiology-Infectious Disease and Immunology, Faculty of Medicine, Université Laval, Quebec City, QC, Canada.
- Big Data Research Centre (BDRC-UL), Université Laval, Faculty of Sciences and engineering, Quebec City, QC, Canada.
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18
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Chaillot J, Tebbji F, García C, Wurtele H, Pelletier R, Sellam A. pH-Dependant Antifungal Activity of Valproic Acid against the Human Fungal Pathogen Candida albicans. Front Microbiol 2017; 8:1956. [PMID: 29062309 PMCID: PMC5640775 DOI: 10.3389/fmicb.2017.01956] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 09/22/2017] [Indexed: 11/20/2022] Open
Abstract
Current antifungal drugs suffer from limitations including toxicity, the emergence of resistance and decreased efficacy at low pH that are typical of human vaginal surfaces. Here, we have shown that the antipsychotic drug valproic acid (VPA) exhibited a strong antifungal activity against both sensitive and resistant Candida albicans in pH condition similar to that encountered in vagina. VPA exerted a strong anti-biofilm activity and attenuated damage of vaginal epithelial cells caused by C. albicans. We also showed that VPA synergizes with the allylamine antifungal, Terbinafine. We undertook a chemogenetic screen to delineate biological processes that underlies VPA-sensitivity in C. albicans and found that vacuole-related genes were required to tolerate VPA. Confocal fluorescence live-cell imaging revealed that VPA alters vacuole integrity and support a model where alteration of vacuoles contributes to the antifungal activity. Taken together, this study suggests that VPA could be used as an effective antifungal against vulvovaginal candidiasis.
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Affiliation(s)
- Julien Chaillot
- Infectious Diseases Research Centre-CRI, Research Center of the CHU de Québec, Université Laval, Quebec, QC, Canada
| | - Faiza Tebbji
- Infectious Diseases Research Centre-CRI, Research Center of the CHU de Québec, Université Laval, Quebec, QC, Canada
| | - Carlos García
- Infectious Diseases Research Centre-CRI, Research Center of the CHU de Québec, Université Laval, Quebec, QC, Canada
| | - Hugo Wurtele
- Maisonneuve-Rosemont Hospital Research Center, Montreal, QC, Canada.,Department of Medicine, Université de Montréal, Montreal, QC, Canada
| | - René Pelletier
- Medical Microbiology and Infectious Diseases, Research Center of the CHU de Québec, Quebec, QC, Canada
| | - Adnane Sellam
- Infectious Diseases Research Centre-CRI, Research Center of the CHU de Québec, Université Laval, Quebec, QC, Canada.,Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, University Laval, Quebec, QC, Canada
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19
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Omar RF, Guilbert E, Gallo MF, Leboeuf M, Boissinot M, Sellam A, Trottier S, Kobinger G, Bergeron MG. Empowerment of Women: Closing the Medical Technologies Gender Gap. J Obstet Gynaecol Can 2017; 40:78-83. [PMID: 28916126 DOI: 10.1016/j.jogc.2017.07.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 07/10/2017] [Accepted: 07/11/2017] [Indexed: 11/18/2022]
Affiliation(s)
- Rabeea F Omar
- Infectious Diseases Research Centre, CHU de Québec-Université Laval and Department of Microbiology, Immunology and Infectiology, Faculty of Medicine, Laval University, Québec City, QC.
| | - Edith Guilbert
- Department of Obstetrics and Gynaecology, Faculty of Medicine, Laval University, Québec City, QC; National Institute of Public Health of Québec, Québec City, QC
| | - Maria F Gallo
- Ohio State University, College of Public Health, Division of Epidemiology, Columbus, OH
| | - Mathieu Leboeuf
- Department of Obstetrics and Gynaecology, Faculty of Medicine, Laval University, Québec City, QC
| | - Maurice Boissinot
- Infectious Diseases Research Centre, CHU de Québec-Université Laval and Department of Microbiology, Immunology and Infectiology, Faculty of Medicine, Laval University, Québec City, QC
| | - Adnane Sellam
- Infectious Diseases Research Centre, CHU de Québec-Université Laval and Department of Microbiology, Immunology and Infectiology, Faculty of Medicine, Laval University, Québec City, QC
| | - Sylvie Trottier
- Infectious Diseases Research Centre, CHU de Québec-Université Laval and Department of Microbiology, Immunology and Infectiology, Faculty of Medicine, Laval University, Québec City, QC
| | - Gary Kobinger
- Infectious Diseases Research Centre, CHU de Québec-Université Laval and Department of Microbiology, Immunology and Infectiology, Faculty of Medicine, Laval University, Québec City, QC
| | - Michel G Bergeron
- Infectious Diseases Research Centre, CHU de Québec-Université Laval and Department of Microbiology, Immunology and Infectiology, Faculty of Medicine, Laval University, Québec City, QC
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20
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Lumbroso L, Sellam A, Coscas F, Dendale R, Levy C, Coscas G, Desjardins L, Cassoux N. Macular features assessed by optical coherence tomography-angiography after proton beam therapy for choroidal melanoma. Acta Ophthalmol 2017. [DOI: 10.1111/j.1755-3768.2017.03646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - A. Sellam
- Ophthalmology; Institut Curie; Paris France
| | - F. Coscas
- Ophthalmology; Centre ophtalmologique de l'Odéon; Paris France
| | - R. Dendale
- Radiation Oncology; Institut Curie; Paris France
| | - C. Levy
- Ophthalmology; Institut Curie; Paris France
| | - G. Coscas
- Ophthalmology; Centre ophtalmologique de l'Odéon; Paris France
| | | | - N. Cassoux
- Ophthalmology; Institut Curie; Paris France
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21
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Salem Y, Nourreddine A, Chefson S, Sellam A, Spanier N. Background variation and radiation-induced darkening of radiophotoluminescent detectors. RADIAT MEAS 2017. [DOI: 10.1016/j.radmeas.2017.07.009] [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: 11/28/2022]
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22
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Chatr-Aryamontri A, Oughtred R, Boucher L, Rust J, Chang C, Kolas NK, O'Donnell L, Oster S, Theesfeld C, Sellam A, Stark C, Breitkreutz BJ, Dolinski K, Tyers M. The BioGRID interaction database: 2017 update. Nucleic Acids Res 2016; 45:D369-D379. [PMID: 27980099 PMCID: PMC5210573 DOI: 10.1093/nar/gkw1102] [Citation(s) in RCA: 666] [Impact Index Per Article: 83.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 10/25/2016] [Accepted: 10/27/2016] [Indexed: 01/05/2023] Open
Abstract
The Biological General Repository for Interaction Datasets (BioGRID: https://thebiogrid.org) is an open access database dedicated to the annotation and archival of protein, genetic and chemical interactions for all major model organism species and humans. As of September 2016 (build 3.4.140), the BioGRID contains 1 072 173 genetic and protein interactions, and 38 559 post-translational modifications, as manually annotated from 48 114 publications. This dataset represents interaction records for 66 model organisms and represents a 30% increase compared to the previous 2015 BioGRID update. BioGRID curates the biomedical literature for major model organism species, including humans, with a recent emphasis on central biological processes and specific human diseases. To facilitate network-based approaches to drug discovery, BioGRID now incorporates 27 501 chemical-protein interactions for human drug targets, as drawn from the DrugBank database. A new dynamic interaction network viewer allows the easy navigation and filtering of all genetic and protein interaction data, as well as for bioactive compounds and their established targets. BioGRID data are directly downloadable without restriction in a variety of standardized formats and are freely distributed through partner model organism databases and meta-databases.
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Affiliation(s)
- Andrew Chatr-Aryamontri
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec H3T 1J4, Canada
| | - Rose Oughtred
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Lorrie Boucher
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Jennifer Rust
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Christie Chang
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Nadine K Kolas
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Lara O'Donnell
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Sara Oster
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Chandra Theesfeld
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Adnane Sellam
- Centre Hospitalier de l'Université Laval (CHUL), Québec, Québec G1V 4G2, Canada
| | - Chris Stark
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Bobby-Joe Breitkreutz
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Kara Dolinski
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Mike Tyers
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec H3T 1J4, Canada .,The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
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23
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Abstract
Candida albicans is an important human fungal pathogen, in terms of both its clinical significance and its use as an experimental model for scientific investigation. Although this opportunistic pathogen is a natural component of the human flora, it can cause life-threatening infections in immunosuppressed patients. There are currently a limited number of antifungal molecules and drug targets, and increasing resistance to the front-line therapeutics, demonstrating a clear need for new antifungal drugs. Understanding the biology of this pathogen is an important prerequisite for identifying new drug targets for antifungal therapeutics. In this review, we highlight some recent developments that help us to understand how virulence traits are regulated at the molecular level, in addition to technical advances that improve the ability of genome editing in C. albicans.
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Affiliation(s)
- Adnane Sellam
- Infectious Diseases Research Centre-CRI, CHU de Québec Research Center (CHUQ), Université Laval, Quebec City, Quebec, Canada; Department of Microbiology, Infectious Disease and Immunology, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
| | - Malcolm Whiteway
- Department of Biology, Concordia University, Montreal, Quebec, Canada
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24
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Capuano V, Sellam A, Miere A, Souied EH, Querques G. [Simultaneous cilioretinal artery and superior hemiretinal vein occlusions: What is the role of hyperhomocysteinemia?]. J Fr Ophtalmol 2016; 39:e279-e281. [PMID: 27745896 DOI: 10.1016/j.jfo.2015.11.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/23/2015] [Accepted: 11/12/2015] [Indexed: 11/27/2022]
Affiliation(s)
- V Capuano
- Department of Ophthalmology, University of Paris-Est-Creteil, centre hospitalier intercommunal de Creteil, 40, avenue de Verdun, 94000 Creteil, France
| | - A Sellam
- Department of Ophthalmology, University of Paris-Est-Creteil, centre hospitalier intercommunal de Creteil, 40, avenue de Verdun, 94000 Creteil, France
| | - A Miere
- Department of Ophthalmology, University of Paris-Est-Creteil, centre hospitalier intercommunal de Creteil, 40, avenue de Verdun, 94000 Creteil, France
| | - E H Souied
- Department of Ophthalmology, University of Paris-Est-Creteil, centre hospitalier intercommunal de Creteil, 40, avenue de Verdun, 94000 Creteil, France
| | - G Querques
- Department of Ophthalmology, University of Paris-Est-Creteil, centre hospitalier intercommunal de Creteil, 40, avenue de Verdun, 94000 Creteil, France.
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25
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Simoneau A, Ricard É, Weber S, Hammond-Martel I, Wong LH, Sellam A, Giaever G, Nislow C, Raymond M, Wurtele H. Chromosome-wide histone deacetylation by sirtuins prevents hyperactivation of DNA damage-induced signaling upon replicative stress. Nucleic Acids Res 2016; 44:2706-26. [PMID: 26748095 PMCID: PMC4824096 DOI: 10.1093/nar/gkv1537] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 12/24/2015] [Indexed: 12/13/2022] Open
Abstract
The Saccharomyces cerevisiae genome encodes five sirtuins (Sir2 and Hst1-4), which constitute a conserved family of NAD-dependent histone deacetylases. Cells lacking any individual sirtuin display mild growth and gene silencing defects. However, hst3Δ hst4Δ double mutants are exquisitely sensitive to genotoxins, and hst3Δ hst4Δ sir2Δmutants are inviable. Our published data also indicate that pharmacological inhibition of sirtuins prevents growth of several fungal pathogens, although the biological basis is unclear. Here, we present genome-wide fitness assays conducted with nicotinamide (NAM), a pan-sirtuin inhibitor. Our data indicate that NAM treatment causes yeast to solicit specific DNA damage response pathways for survival, and that NAM-induced growth defects are mainly attributable to inhibition of Hst3 and Hst4 and consequent elevation of histone H3 lysine 56 acetylation (H3K56ac). Our results further reveal that in the presence of constitutive H3K56ac, the Slx4 scaffolding protein and PP4 phosphatase complex play essential roles in preventing hyperactivation of the DNA damage-response kinase Rad53 in response to spontaneous DNA damage caused by reactive oxygen species. Overall, our data support the concept that chromosome-wide histone deacetylation by sirtuins is critical to mitigate growth defects caused by endogenous genotoxins.
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Affiliation(s)
- Antoine Simoneau
- Maisonneuve-Rosemont Hospital Research Center, 5415 Assomption boulevard, Montreal, H1T 2M4, Canada Molecular biology program, Université de Montréal, P.O. Box 6128, Succursale Centre-ville, Montreal, H3C 3J7, Canada
| | - Étienne Ricard
- Maisonneuve-Rosemont Hospital Research Center, 5415 Assomption boulevard, Montreal, H1T 2M4, Canada Molecular biology program, Université de Montréal, P.O. Box 6128, Succursale Centre-ville, Montreal, H3C 3J7, Canada
| | - Sandra Weber
- Institute for Research in Immunology and Cancer, Université de Montréal, P.O. Box 6128, Succursale Centre-Ville, Montreal, H3C 3J7, Canada
| | - Ian Hammond-Martel
- Maisonneuve-Rosemont Hospital Research Center, 5415 Assomption boulevard, Montreal, H1T 2M4, Canada Molecular biology program, Université de Montréal, P.O. Box 6128, Succursale Centre-ville, Montreal, H3C 3J7, Canada
| | - Lai Hong Wong
- Department of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - Adnane Sellam
- Infectious Diseases Research Centre-CRI, CHU de Québec Research Center (CHUQ), Université Laval, Québec, G1V 4G2, Canada Department of Microbiology-Infectious Disease and Immunology, Faculty of Medicine, Université Laval, Québec, G1V 0A6, Canada
| | - Guri Giaever
- Department of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - Corey Nislow
- Department of Pharmaceutical Sciences, University of British Columbia, Vancouver, V6T 1Z3, Canada
| | - Martine Raymond
- Institute for Research in Immunology and Cancer, Université de Montréal, P.O. Box 6128, Succursale Centre-Ville, Montreal, H3C 3J7, Canada Department of Biochemistry and Molecular Medicine, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, H3C 3J7, Canada
| | - Hugo Wurtele
- Maisonneuve-Rosemont Hospital Research Center, 5415 Assomption boulevard, Montreal, H1T 2M4, Canada Department of Medicine, Université de Montréal, Montreal, H3T 1J4, Canada
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26
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Oughtred R, Chatr-aryamontri A, Breitkreutz BJ, Chang CS, Rust JM, Theesfeld CL, Heinicke S, Breitkreutz A, Chen D, Hirschman J, Kolas N, Livstone MS, Nixon J, O'Donnell L, Ramage L, Winter A, Reguly T, Sellam A, Stark C, Boucher L, Dolinski K, Tyers M. BioGRID: A Resource for Studying Biological Interactions in Yeast. Cold Spring Harb Protoc 2016; 2016:pdb.top080754. [PMID: 26729913 DOI: 10.1101/pdb.top080754] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The Biological General Repository for Interaction Datasets (BioGRID) is a freely available public database that provides the biological and biomedical research communities with curated protein and genetic interaction data. Structured experimental evidence codes, an intuitive search interface, and visualization tools enable the discovery of individual gene, protein, or biological network function. BioGRID houses interaction data for the major model organism species--including yeast, nematode, fly, zebrafish, mouse, and human--with particular emphasis on the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe as pioneer eukaryotic models for network biology. BioGRID has achieved comprehensive curation coverage of the entire literature for these two major yeast models, which is actively maintained through monthly curation updates. As of September 2015, BioGRID houses approximately 335,400 biological interactions for budding yeast and approximately 67,800 interactions for fission yeast. BioGRID also supports an integrated posttranslational modification (PTM) viewer that incorporates more than 20,100 yeast phosphorylation sites curated through its sister database, the PhosphoGRID.
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Affiliation(s)
- Rose Oughtred
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544
| | - Andrew Chatr-aryamontri
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Bobby-Joe Breitkreutz
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Christie S Chang
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544
| | - Jennifer M Rust
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544
| | - Chandra L Theesfeld
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544
| | - Sven Heinicke
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544
| | - Ashton Breitkreutz
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Daici Chen
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Jodi Hirschman
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544
| | - Nadine Kolas
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Michael S Livstone
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544
| | - Julie Nixon
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JR, United Kingdom
| | - Lara O'Donnell
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Lindsay Ramage
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JR, United Kingdom
| | - Andrew Winter
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JR, United Kingdom
| | - Teresa Reguly
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Adnane Sellam
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Chris Stark
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Lorrie Boucher
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Kara Dolinski
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544
| | - Mike Tyers
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H3C 3J7, Canada; Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada; School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JR, United Kingdom
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27
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Sellam A, Massamba N, Le Hoang P, Bodaghi B. Imagerie multimodale d’une maculopathie liée aux antipaludéens de synthèse. J Fr Ophtalmol 2016; 39:111-3. [DOI: 10.1016/j.jfo.2015.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 05/22/2015] [Accepted: 06/11/2015] [Indexed: 11/17/2022]
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28
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Sellam A, Massamba N, Fel A, LeHoang P, Bodaghi B. Hyperreflective Dots in Spectral Domain Optical Coherence Tomography as Phenotypic Marker in Uveitis-Associated Cystoid Macular Edema. Acta Ophthalmol 2015. [DOI: 10.1111/j.1755-3768.2015.0508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- A. Sellam
- Ophthalmology; Hôpital Pitié Salpétrière; Paris France
| | - N. Massamba
- Ophthalmology; Hôpital Pitié Salpétrière; Paris France
| | - A. Fel
- Ophthalmology; Hôpital Pitié Salpétrière; Paris France
| | - P. LeHoang
- Ophthalmology; Hôpital Pitié Salpétrière; Paris France
| | - B. Bodaghi
- Ophthalmology; Hôpital Pitié Salpétrière; Paris France
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29
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Sellam A, Fournier I, Biton-Ouayoun C. Paralysie isolée du VI gauche révélant une maladie de Lyme chez un garçon de 11ans. J Fr Ophtalmol 2015; 38:e155-6. [DOI: 10.1016/j.jfo.2014.06.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2014] [Revised: 06/24/2014] [Accepted: 06/30/2014] [Indexed: 11/29/2022]
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30
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Sellam A, Chahwakilian P, Cohen R, Béchet S, Vie Le Sage F, Lévy C. Impact des recommandations sur la prescription en consultation de ville d’antibiotiques à l’enfant. Arch Pediatr 2015; 22:595-601. [DOI: 10.1016/j.arcped.2015.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 12/12/2014] [Accepted: 03/13/2015] [Indexed: 11/25/2022]
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31
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Osswald F, Bouquerel E, Boutin D, Dinkov A, Kazarinov N, Perrot L, Sellam A. Transport of radioactive ion beams and related safety issues: the 132Sn+ case study. Rev Sci Instrum 2014; 85:123301. [PMID: 25554283 DOI: 10.1063/1.4902148] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The transport of intense radioactive ion beam currents requires a careful design in order to limit the beam losses, the contamination and thus the dose rates. Some investigations based on numerical models and calculations have been performed in the framework of the SPIRAL 2 project to evaluate the performance of a low energy beam transport line located between the isotope separation on line (ISOL) production cell and the experiment areas. The paper presents the results of the transverse phase-space analysis, the beam losses assessment, the resulting contamination, and radioactivity levels. They show that reasonable beam transmission, emittance growth, and dose rates can be achieved considering the current standards.
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Affiliation(s)
- F Osswald
- IPHC/IN2P3/CNRS, University of Strasbourg, 67037 Strasbourg, France
| | - E Bouquerel
- IPHC/IN2P3/CNRS, University of Strasbourg, 67037 Strasbourg, France
| | - D Boutin
- IPHC/IN2P3/CNRS, University of Strasbourg, 67037 Strasbourg, France
| | - A Dinkov
- IPHC/IN2P3/CNRS, University of Strasbourg, 67037 Strasbourg, France
| | | | - L Perrot
- IPNO/IN2P3/CNRS, University of Paris-Sud-11, 91406 Orsay, France
| | - A Sellam
- IPHC/IN2P3/CNRS, University of Strasbourg, 67037 Strasbourg, France
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32
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Gasser E, Nachab A, Nourreddine A, Roy C, Sellam A. Update of (40)K and (226)Ra and (232)Th series γ-to-dose conversion factors for soil. J Environ Radioact 2014; 138:68-71. [PMID: 25173948 DOI: 10.1016/j.jenvrad.2014.08.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 07/22/2014] [Accepted: 08/04/2014] [Indexed: 06/03/2023]
Abstract
Over the last four decades, the dose conversion factors used to calculate external exposure to γ radiation from soil from (40)K and the (226)Ra and (232)Th chains have been 0.62, 0.042 and 0.46 (nGy/h per Bq/kg), respectively. This work updates these γ-to-dose conversion factors, taking into consideration the composition, depth and radius of the soil source, and importantly, updated branching ratios, with MCNPX simulations. The new conversion factors are 0.036, 0.357 and 0.482 (nGy/h per Bq/kg) for (40)K and the (226)Ra and (232)Th chains, respectively.
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Affiliation(s)
- E Gasser
- Groupe RaMsEs, Institut Pluridisciplinaire Hubert Curien, UMR 7178 CNRS/IN2P3, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2, France
| | - A Nachab
- Département de physique, Faculté Poly-disciplinaire de Safi, Université Cadi Ayyad, Route Sidi Bouzid BP 4162, 46000 Safi, Morocco.
| | - A Nourreddine
- Groupe RaMsEs, Institut Pluridisciplinaire Hubert Curien, UMR 7178 CNRS/IN2P3, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2, France
| | - Ch Roy
- Groupe RaMsEs, Institut Pluridisciplinaire Hubert Curien, UMR 7178 CNRS/IN2P3, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2, France
| | - A Sellam
- Groupe RaMsEs, Institut Pluridisciplinaire Hubert Curien, UMR 7178 CNRS/IN2P3, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2, France
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33
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Sellam A, Fournier I, Biton-Ouayoun C. Description en tomographie par cohérence optique d’une occlusion artérielle de rétine. J Fr Ophtalmol 2014; 37:833. [DOI: 10.1016/j.jfo.2014.04.020] [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] [Received: 03/14/2014] [Revised: 04/24/2014] [Accepted: 04/25/2014] [Indexed: 11/28/2022]
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34
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Chatr-Aryamontri A, Breitkreutz BJ, Oughtred R, Boucher L, Heinicke S, Chen D, Stark C, Breitkreutz A, Kolas N, O'Donnell L, Reguly T, Nixon J, Ramage L, Winter A, Sellam A, Chang C, Hirschman J, Theesfeld C, Rust J, Livstone MS, Dolinski K, Tyers M. The BioGRID interaction database: 2015 update. Nucleic Acids Res 2014; 43:D470-8. [PMID: 25428363 PMCID: PMC4383984 DOI: 10.1093/nar/gku1204] [Citation(s) in RCA: 648] [Impact Index Per Article: 64.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The Biological General Repository for Interaction Datasets (BioGRID: http://thebiogrid.org) is an open access database that houses genetic and protein interactions curated from the primary biomedical literature for all major model organism species and humans. As of September 2014, the BioGRID contains 749 912 interactions as drawn from 43 149 publications that represent 30 model organisms. This interaction count represents a 50% increase compared to our previous 2013 BioGRID update. BioGRID data are freely distributed through partner model organism databases and meta-databases and are directly downloadable in a variety of formats. In addition to general curation of the published literature for the major model species, BioGRID undertakes themed curation projects in areas of particular relevance for biomedical sciences, such as the ubiquitin-proteasome system and various human disease-associated interaction networks. BioGRID curation is coordinated through an Interaction Management System (IMS) that facilitates the compilation interaction records through structured evidence codes, phenotype ontologies, and gene annotation. The BioGRID architecture has been improved in order to support a broader range of interaction and post-translational modification types, to allow the representation of more complex multi-gene/protein interactions, to account for cellular phenotypes through structured ontologies, to expedite curation through semi-automated text-mining approaches, and to enhance curation quality control.
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Affiliation(s)
- Andrew Chatr-Aryamontri
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec H3C 3J7, Canada
| | - Bobby-Joe Breitkreutz
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Rose Oughtred
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Lorrie Boucher
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Sven Heinicke
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Daici Chen
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec H3C 3J7, Canada
| | - Chris Stark
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Ashton Breitkreutz
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Nadine Kolas
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Lara O'Donnell
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Teresa Reguly
- The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | - Julie Nixon
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, UK
| | - Lindsay Ramage
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, UK
| | - Andrew Winter
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, UK
| | - Adnane Sellam
- Centre Hospitalier de l'Université Laval (CHUL), Québec, Québec G1V 4G2, Canada
| | - Christie Chang
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Jodi Hirschman
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Chandra Theesfeld
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Jennifer Rust
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Michael S Livstone
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Kara Dolinski
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Mike Tyers
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec H3C 3J7, Canada The Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, UK
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Chatr-Aryamontri A, Breitkreutz BJ, Heinicke S, Boucher L, Winter A, Stark C, Nixon J, Ramage L, Kolas N, O'Donnell L, Reguly T, Breitkreutz A, Sellam A, Chen D, Chang C, Rust J, Livstone M, Oughtred R, Dolinski K, Tyers M. The BioGRID interaction database: 2013 update. Nucleic Acids Res 2012. [PMID: 23203989 PMCID: PMC3531226 DOI: 10.1093/nar/gks1158] [Citation(s) in RCA: 502] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The Biological General Repository for Interaction Datasets (BioGRID: http//thebiogrid.org) is an open access archive of genetic and protein interactions that are curated from the primary biomedical literature for all major model organism species. As of September 2012, BioGRID houses more than 500 000 manually annotated interactions from more than 30 model organisms. BioGRID maintains complete curation coverage of the literature for the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe and the model plant Arabidopsis thaliana. A number of themed curation projects in areas of biomedical importance are also supported. BioGRID has established collaborations and/or shares data records for the annotation of interactions and phenotypes with most major model organism databases, including Saccharomyces Genome Database, PomBase, WormBase, FlyBase and The Arabidopsis Information Resource. BioGRID also actively engages with the text-mining community to benchmark and deploy automated tools to expedite curation workflows. BioGRID data are freely accessible through both a user-defined interactive interface and in batch downloads in a wide variety of formats, including PSI-MI2.5 and tab-delimited files. BioGRID records can also be interrogated and analyzed with a series of new bioinformatics tools, which include a post-translational modification viewer, a graphical viewer, a REST service and a Cytoscape plugin.
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Affiliation(s)
- Andrew Chatr-Aryamontri
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Quebec, Canada H3C 3J7
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Ryan O, Shapiro RS, Kurat CF, Mayhew D, Baryshnikova A, Chin B, Lin ZY, Cox MJ, Vizeacoumar F, Cheung D, Bahr S, Tsui K, Tebbji F, Sellam A, Istel F, Schwarzmuller T, Reynolds TB, Kuchler K, Gifford DK, Whiteway M, Giaever G, Nislow C, Costanzo M, Gingras AC, Mitra RD, Andrews B, Fink GR, Cowen LE, Boone C. Global Gene Deletion Analysis Exploring Yeast Filamentous Growth. Science 2012; 337:1353-6. [DOI: 10.1126/science.1224339] [Citation(s) in RCA: 162] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Sellam A, Tebbji F, Whiteway M, Nantel A. A novel role for the transcription factor Cwt1p as a negative regulator of nitrosative stress in Candida albicans. PLoS One 2012; 7:e43956. [PMID: 22952822 PMCID: PMC3430608 DOI: 10.1371/journal.pone.0043956] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 07/27/2012] [Indexed: 11/21/2022] Open
Abstract
The ability of Candida albicans to survive in the presence of nitrosative stress during the initial contact with the host immune system is crucial for its ability to colonize mammalian hosts. Thus, this fungus must activate robust mechanisms to neutralize and repair nitrosative-induced damage. Until now, very little was known regarding the regulatory circuits associated with reactive nitrogen species detoxification in fungi. To gain insight into the transcriptional regulatory networks controlling nitrosative stress response (NRS) in C. albicans a compilation of transcriptional regulator-defective mutants were screened. This led to the identification of Cwt1p as a negative regulator of NSR. By combining genome-wide location and expression analyses, we have characterized the Cwt1p regulon and demonstrated that Cwt1p is directly required for proper repression of the flavohemoglobin Yhb1p, a key NO-detoxification enzyme. Furthermore, Cwt1p operates both by activating and repressing genes of specific functions solicited upon NSR. Additionally, we used Gene Set Enrichment Analysis to reinvestigate the C. albicans NSR-transcriptome and demonstrate a significant similarity with the transcriptional profiles of C. albicans interacting with phagocytic host-cells. In summary, we have characterized a novel negative regulator of NSR and bring new insights into the transcriptional regulatory network governing fungal NSR.
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Affiliation(s)
- Adnane Sellam
- Institute for Research in Immunology and Cancer (IRIC), University of Montreal, Montréal, QC, Canada
- * E-mail: (AS); (AN)
| | - Faiza Tebbji
- Biotechnology Research Institute, National Research Council of Canada, Montréal, QC, Canada
- Department of Biology, McGill University, Montréal, QC, Canada
| | - Malcolm Whiteway
- Biotechnology Research Institute, National Research Council of Canada, Montréal, QC, Canada
- Department of Biology, McGill University, Montréal, QC, Canada
| | - André Nantel
- Biotechnology Research Institute, National Research Council of Canada, Montréal, QC, Canada
- Department of Anatomy and Cell Biology, McGill University, Montréal, QC, Canada
- * E-mail: (AS); (AN)
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Shapiro RS, Sellam A, Tebbji F, Whiteway M, Nantel A, Cowen LE. Pho85, Pcl1, and Hms1 signaling governs Candida albicans morphogenesis induced by high temperature or Hsp90 compromise. Curr Biol 2012; 22:461-70. [PMID: 22365851 DOI: 10.1016/j.cub.2012.01.062] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 01/13/2012] [Accepted: 01/30/2012] [Indexed: 12/14/2022]
Abstract
BACKGROUND Temperature exerts powerful control over development and virulence of diverse pathogens. In the leading human fungal pathogen, Candida albicans, temperature governs morphogenesis, a key virulence trait. Many cues that induce the yeast to filament transition are contingent on a minimum of 37°C, whereas further elevation to 39°C serves as an independent inducer. The molecular chaperone Hsp90 is a key regulator of C. albicans temperature-dependent morphogenesis. Compromise of Hsp90 function genetically, pharmacologically, or by elevated temperature induces filamentation in a manner that depends on protein kinase A signaling but is independent of the terminal transcription factor, Efg1. RESULTS Here, we establish that despite morphological and regulatory differences, inhibition of Hsp90 induces a transcriptional profile similar to that induced by other filamentation cues and does so independently of Efg1. Further, we identify Hms1 as a transcriptional regulator required for morphogenesis induced by elevated temperature or Hsp90 compromise. Hms1 functions downstream of the cyclin Pcl1 and the cyclin-dependent kinase Pho85, both of which are required for temperature-dependent filamentation. Upon Hsp90 inhibition, Hms1 binds to DNA elements involved in filamentous growth, including UME6 and RBT5, and regulates their expression, providing a mechanism through which Pho85, Pcl1, and Hms1 govern morphogenesis. Consistent with the importance of morphogenetic flexibility for virulence, deletion of C. albicans HMS1 attenuates virulence in a metazoan model of infection. CONCLUSIONS Thus, we establish a new mechanism through which Hsp90 orchestrates C. albicans morphogenesis, and define novel regulatory circuitry governing a temperature-dependent developmental program, with broad implications for temperature sensing and virulence of microbial pathogens.
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Affiliation(s)
- Rebecca S Shapiro
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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Dziri S, Nourreddine A, Sellam A, Pape A, Baussan E. Simulation approach to coincidence summing in γ-ray spectrometry. Appl Radiat Isot 2011; 70:1141-4. [PMID: 21992843 DOI: 10.1016/j.apradiso.2011.09.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 09/20/2011] [Accepted: 09/21/2011] [Indexed: 11/16/2022]
Abstract
Some of the radionuclides used for efficiency calibration of a HPGe spectrometer are subject to coincidence-summing (CS) and account must be taken of the phenomenon to obtain quantitative results when counting samples to determine their activity. We have used MCNPX simulations, which do not take CS into account, to obtain γ-ray peak intensities that were compared to those observed experimentally. The loss or gain of a measured peak intensity relative to the simulated peak is attributed to CS. CS correction factors are compared with those of ETNA and GESPECOR. Application to a test sample prepared with known radionuclides gave values close to the published activities.
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Affiliation(s)
- S Dziri
- Groupe RaMsEs, Institut Pluridisciplinaire Hubert Curien (IPHC), University of Strasbourg, CNRS, IN2P3, UMR 7178, 23 rue de Loess, BP 28, 67037 Strasbourg Cedex 2, France.
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Askew C, Sellam A, Epp E, Mallick J, Hogues H, Mullick A, Nantel A, Whiteway M. The zinc cluster transcription factor Ahr1p directs Mcm1p regulation of Candida albicans adhesion. Mol Microbiol 2010; 79:940-53. [PMID: 21299649 DOI: 10.1111/j.1365-2958.2010.07504.x] [Citation(s) in RCA: 40] [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: 11/30/2022]
Abstract
Biofilm development by Candida albicans requires cell adhesion for the initial establishment of the biofilm and the continued stability after hyphal development occurs; however, the regulation of the process has not been fully established. Using chromatin immunoprecipitation coupled to microarray analysis (ChIP-chip) we have characterized a regulon containing the Mcm1p factor that is required for the initial surface adhesion during biofilm formation. In the yeast Saccharomyces cerevisiae several Mcm1p regulons have been characterized in which regulatory specificity is achieved through cofactors binding a sequence adjacent to the Mcm1p binding site. This new Mcm1p regulon in C. albicans also requires a cofactor, which we identify as the transcription factor Ahr1p. However, in contrast to the other yeast regulons, Ahr1p alone binds the target promoters, which include several key adhesion genes, and recruits Mcm1p to these sites. Through transcription profiling and qPCR analysis, we demonstrate that this Ahr1p-Mcm1p complex directly activates these adhesion genes. When the regulatory circuit was disrupted by deleting AHR1, the strain displayed reduced adherence to a polystyrene surface. We also demonstrate a role for the regulon in hyphal growth and in virulence. Our work thus establishes a new mechanism of Mcm1p-directed regulation distinct from those observed for other Mcm1p co-regulators.
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Affiliation(s)
- Christopher Askew
- Biotechnology Research Institute, National Research Council of Canada, Montréal, Québec, Canada H4P 2R2
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41
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Sellam A, Hogues H, Askew C, Tebbji F, van Het Hoog M, Lavoie H, Kumamoto CA, Whiteway M, Nantel A. Experimental annotation of the human pathogen Candida albicans coding and noncoding transcribed regions using high-resolution tiling arrays. Genome Biol 2010; 11:R71. [PMID: 20618945 PMCID: PMC2926782 DOI: 10.1186/gb-2010-11-7-r71] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 06/07/2010] [Accepted: 07/09/2010] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Compared to other model organisms and despite the clinical relevance of the pathogenic yeast Candida albicans, no comprehensive analysis has been done to provide experimental support of its in silico-based genome annotation. RESULTS We have undertaken a genome-wide experimental annotation to accurately uncover the transcriptional landscape of the pathogenic yeast C. albicans using strand-specific high-density tiling arrays. RNAs were purified from cells growing under conditions relevant to C. albicans pathogenicity, including biofilm, lab-grown yeast and serum-induced hyphae, as well as cells isolated from the mouse caecum. This work provides a genome-wide experimental validation for a large number of predicted ORFs for which transcription had not been detected by other approaches. Additionally, we identified more than 2,000 novel transcriptional segments, including new ORFs and exons, non-coding RNAs (ncRNAs) as well as convincing cases of antisense gene transcription. We also characterized the 5' and 3' UTRs of expressed ORFs, and established that genes with long 5' UTRs are significantly enriched in regulatory functions controlling filamentous growth. Furthermore, we found that genomic regions adjacent to telomeres harbor a cluster of expressed ncRNAs. To validate and confirm new ncRNA candidates, we adapted an iterative strategy combining both genome-wide occupancy of the different subunits of RNA polymerases I, II and III and expression data. This comprehensive approach allowed the identification of different families of ncRNAs. CONCLUSIONS In summary, we provide a comprehensive expression atlas that covers relevant C. albicans pathogenic developmental stages in addition to the discovery of new ORF and non-coding genetic elements.
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Affiliation(s)
- Adnane Sellam
- Biotechnology Research Institute, National Research Council of Canada, 6100 Royalmount, Montréal, Québec, H4P 2R2, Canada.
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Lavoie H, Hogues H, Mallick J, Sellam A, Nantel A, Whiteway M. Evolutionary tinkering with conserved components of a transcriptional regulatory network. PLoS Biol 2010; 8:e1000329. [PMID: 20231876 PMCID: PMC2834713 DOI: 10.1371/journal.pbio.1000329] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Accepted: 02/03/2010] [Indexed: 12/14/2022] Open
Abstract
A surprising level of evolutionary plasticity is revealed by analysis of differences between related yeasts in the mechanisms regulating the essential cellular process of ribosomal gene expression. Gene expression variation between species is a major contributor to phenotypic diversity, yet the underlying flexibility of transcriptional regulatory networks remains largely unexplored. Transcription of the ribosomal regulon is a critical task for all cells; in S. cerevisiae the transcription factors Rap1, Fhl1, Ifh1, and Hmo1 form a multi-subunit complex that controls ribosomal gene expression, while in C. albicans this regulation is under the control of Tbf1 and Cbf1. Here, we analyzed, using full-genome transcription factor mapping, the roles, in both S. cerevisiae and C. albicans, of each orthologous component of this complete set of regulators. We observe dramatic changes in the binding profiles of the generalist regulators Cbf1, Hmo1, Rap1, and Tbf1, while the Fhl1-Ifh1 dimer is the only component involved in ribosomal regulation in both fungi: it activates ribosomal protein genes and rDNA expression in a Tbf1-dependent manner in C. albicans and a Rap1-dependent manner in S. cerevisiae. We show that the transcriptional regulatory network governing the ribosomal expression program of two related yeast species has been massively reshaped in cis and trans. Changes occurred in transcription factor wiring with cellular functions, movements in transcription factor hierarchies, DNA-binding specificity, and regulatory complexes assembly to promote global changes in the architecture of the fungal transcriptional regulatory network. Conserved metabolic machineries direct energy production and investment in most life forms. However, variation in the transcriptional regulation of the genes that encode this machinery has been observed and shown to contribute to phenotypic differences between species. Here, we show that the regulatory circuits governing the expression of central metabolic components (in this case the ribosomes) in different yeast species have an unexpected level of evolutionary plasticity. Most transcription factors involved in the regulation of expression of ribosomal genes have in fact been reused in new ways during the evolutionary time separating S. cerevisiae and C. albicans to generate global changes in transcriptional network structures and new ribosomal regulatory complexes.
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Affiliation(s)
- Hugo Lavoie
- Biotechnology Research Institute, National Research Council, Montreal, Quebec, Canada
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Hervé Hogues
- Biotechnology Research Institute, National Research Council, Montreal, Quebec, Canada
| | - Jaideep Mallick
- Biotechnology Research Institute, National Research Council, Montreal, Quebec, Canada
| | - Adnane Sellam
- Biotechnology Research Institute, National Research Council, Montreal, Quebec, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - André Nantel
- Biotechnology Research Institute, National Research Council, Montreal, Quebec, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Malcolm Whiteway
- Biotechnology Research Institute, National Research Council, Montreal, Quebec, Canada
- Department of Biology, McGill University, Montreal, Quebec, Canada
- * E-mail:
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Askew C, Sellam A, Epp E, Hogues H, Mullick A, Nantel A, Whiteway M. Transcriptional regulation of carbohydrate metabolism in the human pathogen Candida albicans. PLoS Pathog 2009; 5:e1000612. [PMID: 19816560 PMCID: PMC2749448 DOI: 10.1371/journal.ppat.1000612] [Citation(s) in RCA: 184] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 09/10/2009] [Indexed: 11/22/2022] Open
Abstract
Glycolysis is a metabolic pathway that is central to the assimilation of carbon for either respiration or fermentation and therefore is critical for the growth of all organisms. Consequently, glycolytic transcriptional regulation is important for the metabolic flexibility of pathogens in their attempts to colonize diverse niches. We investigated the transcriptional control of carbohydrate metabolism in the human fungal pathogen Candida albicans and identified two factors, Tye7p and Gal4p, as key regulators of glycolysis. When respiration was inhibited or oxygen was limited, a gal4tye7 C. albicans strain showed a severe growth defect when cultured on glucose, fructose or mannose as carbon sources. The gal4tye7 strain displayed attenuated virulence in both Galleria and mouse models as well, supporting the connection between pathogenicity and metabolism. Chromatin immunoprecipitation coupled with microarray analysis (ChIP-CHIP) and transcription profiling revealed that Tye7p bound the promoter sequences of the glycolytic genes and activated their expression during growth on either fermentable or non-fermentable carbon sources. Gal4p also bound the glycolytic promoter sequences and activated the genes although to a lesser extent than Tye7p. Intriguingly, binding and activation by Gal4p was carbon source-dependent and much stronger during growth on media containing fermentable sugars than on glycerol. Furthermore, Tye7p and Gal4p were responsible for the complete induction of the glycolytic genes under hypoxic growth conditions. Tye7p and Gal4p also regulated unique sets of carbohydrate metabolic genes; Tye7p bound and activated genes involved in trehalose, glycogen, and glycerol metabolism, while Gal4p regulated the pyruvate dehydrogenase complex. This suggests that Tye7p represents the key transcriptional regulator of carbohydrate metabolism in C. albicans and Gal4p provides a carbon source-dependent fine-tuning of gene expression while regulating the metabolic flux between respiration and fermentation pathways. Pathogens must be able to assimilate the carbon sources in their environment to generate sufficient energy and metabolites to survive. Since glycolysis is a central metabolic pathway, it is important for this metabolic flexibility. The most commonly isolated agent in human fungal infections, Candida albicans, depends upon glycolysis for the progression of systemic disease. We investigated glycolytic transcriptional regulation in C. albicans and defined two key regulators of the pathway, Tye7p and Gal4p. We demonstrated that these factors are important for the fermentative growth of C. albicans both in vitro and in vivo and also regulate the input and output fluxes of glycolysis. The gal4tye7 strain showed attenuated virulence in a Galleria and two mouse models, potentially due to the severe growth defect in oxygen-limiting environments. Gal4p and Tye7p represent fungal specific regulators involved in the pathogenicity of the organism that may be exploited in the development of antifungal treatments. Our study describes a fungal glycolytic transcriptional circuit that is fundamentally different from that of the model yeast Saccharomyces cerevisiae, providing further evidence that the transcriptional networks in S. cerevisiae need not be generally representative of the fungal kingdom.
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Affiliation(s)
- Christopher Askew
- Biotechnology Research Institute, National Research Council of Canada, Montréal, Québec, Canada
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Arbour M, Epp E, Hogues H, Sellam A, Lacroix C, Rauceo J, Mitchell A, Whiteway M, Nantel A. Widespread occurrence of chromosomal aneuploidy following the routine production of Candida albicans mutants. FEMS Yeast Res 2009; 9:1070-7. [PMID: 19732157 PMCID: PMC2784216 DOI: 10.1111/j.1567-1364.2009.00563.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
It has come to our attention that approximately 35% of >100 published microarray datasets, where transcript levels were compared between two different strains, exhibit some form of chromosome-specific bias. While some of these arose from the use of strains whose aneuploidies were not known at the time, in a worrisome number of cases the recombinant strains have acquired additional aneuploidies that were not initially present in the parental strain. The aneuploidies often affected a different chromosome than the one harboring the insertion site. The affected strains originated from either CAI-4, RM1000, BWP17 or SN95 and were produced through a variety of strategies. These observations suggest that aneuploidies frequently occur during the production of recombinant strains and have an effect on global transcript profiles outside of the afflicted chromosome(s), thus raising the possibility of unintended phenotypic consequences. Thus, we propose that all Candida albicans mutants and strains should be tested for aneuploidy before being used in further studies. To this end, we describe a new rapid testing method, based on a multiplex quantitative PCR assay, that produces eight bands of distinct sizes from either the left or right arms of each C. albicans chromosome.
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Affiliation(s)
- Mélanie Arbour
- Biotechnology Research Institute, National Research Council of Canada, Montreal, QC, Canada H4P2R2
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Sellam A, Askew C, Epp E, Lavoie H, Whiteway M, Nantel A. Genome-wide mapping of the coactivator Ada2p yields insight into the functional roles of SAGA/ADA complex in Candida albicans. Mol Biol Cell 2009; 20:2389-400. [PMID: 19279142 DOI: 10.1091/mbc.e08-11-1093] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The SAGA/ADA coactivator complex, which regulates numerous cellular processes by coordinating histone acetylation, is widely conserved throughout eukaryotes, and analysis of the Candida albicans genome identifies the components of this complex in the fungal pathogen. We investigated the multiple functions of SAGA/ADA in C. albicans by determining the genome-wide occupancy of Ada2p using chromatin immunoprecipitation (ChIP). Ada2p is recruited to 200 promoters upstream of genes involved in different stress-response functions and metabolic processes. Phenotypic and transcriptomic analysis of ada2 mutant showed that Ada2p is required for the responses to oxidative stress, as well as to treatments with tunicamycin and fluconazole. Ada2p recruitment to the promoters of oxidative resistance genes is mediated by the transcription factor Cap1p, and coactivator function were also established for Gal4p, which recruits Ada2p to the promoters of glycolysis and pyruvate metabolism genes. Cooccupancy of Ada2p and the drug resistance regulator Mrr1p on the promoters of core resistance genes characterizing drug resistance in clinical strains was also demonstrated. Ada2p recruitment to the promoters of these genes were shown to be completely dependent on Mrr1p. Furthermore, ADA2 deletion causes a decrease in H3K9 acetylation levels of target genes, thus illustrating its importance for histone acetyl transferase activity.
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Affiliation(s)
- Adnane Sellam
- Biotechnology Research Institute, National Research Council of Canada, Montréal, QC, H4P 2R2, Canada
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Sellam A, Al-Niemi T, McInnerney K, Brumfield S, Nantel A, Suci PA. A Candida albicans early stage biofilm detachment event in rich medium. BMC Microbiol 2009; 9:25. [PMID: 19187560 PMCID: PMC2647545 DOI: 10.1186/1471-2180-9-25] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 02/02/2009] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Dispersal from Candida albicans biofilms that colonize catheters is implicated as a primary factor in the link between contaminated catheters and life threatening blood stream infections (BSI). Appropriate in vitro C. albicans biofilm models are needed to probe factors that induce detachment events. RESULTS Using a flow through system to culture C. albicans biofilms we characterized a detachment process which culminates in dissociation of an entire early stage biofilm from a silicone elastomer surface. We analyzed the transcriptome response at time points that bracketed an abrupt transition in which a strong adhesive association with the surface is weakened in the initial stages of the process, and also compared batch and biofilm cultures at relevant time points. K means analysis of the time course array data revealed categories of genes with similar patterns of expression that were associated with adhesion, biofilm formation and glycoprotein biosynthesis. Compared to batch cultures the biofilm showed a pattern of expression of metabolic genes that was similar to the C. albicans response to hypoxia. However, the loss of strong adhesion was not obviously influenced by either the availability of oxygen in the medium or at the silicone elastomer surface. The detachment phenotype of mutant strains in which selected genes were either deleted or overexpressed was characterized. The microarray data indicated that changes associated with the detachment process were complex and, consistent with this assessment, we were unable to demonstrate that transcriptional regulation of any single gene was essential for loss of the strong adhesive association. CONCLUSION The massive dispersal of the early stage biofilm from a biomaterial surface that we observed is not orchestrated at the level of transcriptional regulation in an obvious manner, or is only regulated at this level by a small subpopulation of cells that mediate adhesion to the surface.
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Affiliation(s)
- Adnane Sellam
- Biotechnology Research Institute, National Research Council of Canada, Montreal, Quebec, Canada.
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Lavoie H, Sellam A, Askew C, Nantel A, Whiteway M. A toolbox for epitope-tagging and genome-wide location analysis in Candida albicans. BMC Genomics 2008; 9:578. [PMID: 19055720 PMCID: PMC2607300 DOI: 10.1186/1471-2164-9-578] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Accepted: 12/02/2008] [Indexed: 11/29/2022] Open
Abstract
Background Candida albicans is a diploid pathogenic fungus not yet amenable to routine genetic investigations. Understanding aspects of the regulation of its biological functions and the assembly of its protein complexes would lead to further insight into the biology of this common disease-causing microbial agent. Results We have developed a toolbox allowing in vivo protein tagging by PCR-mediated homologous recombination with TAP, HA and MYC tags. The transformation cassettes were designed to accommodate a common set of integration primers. The tagged proteins can be used to perform tandem affinity purification (TAP) or chromatin immunoprecipitation coupled with microarray analysis (ChIP-CHIP). Tandem affinity purification of C. albicans Nop1 revealed the high conservation of the small processome composition in yeasts. Data obtained with in vivo TAP-tagged Tbf1, Cbf1 and Mcm1 recapitulates previously published genome-wide location profiling by ChIP-CHIP. We also designed a new reporter system for in vivo analysis of transcriptional activity of gene loci in C. albicans. Conclusion This toolbox provides a basic setup to perform purification of protein complexes and increase the number of annotated transcriptional regulators and genetic circuits in C. albicans.
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Affiliation(s)
- Hugo Lavoie
- Biotechnology Research Institute, National Research Council, Montreal, Quebec, H4P 2R2, Canada.
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Avenot HF, Sellam A, Karaoglanidis G, Michailides TJ. Characterization of mutations in the iron-sulphur subunit of succinate dehydrogenase correlating with Boscalid resistance in Alternaria alternata from California pistachio. Phytopathology 2008; 98:736-742. [PMID: 18944299 DOI: 10.1094/phyto-98-6-0736] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Thirty-eight isolates of Alternaria alternata from pistachio orchards with a history of Pristine (pyraclostrobin + boscalid) applications and displaying high levels of resistance to boscalid fungicide (mean EC(50) values >500 microg/ml) were identified following mycelial growth tests. A cross-resistance study revealed that the same isolates were also resistant to carboxin, a known inhibitor of succinate dehydrogenase (Sdh). To determine the genetic basis of boscalid resistance in A. alternata the entire iron sulphur gene (AaSdhB) was isolated from a fungicide-sensitive isolate. The deduced amino-acid sequence showed high similarity with iron sulphur proteins (Ip) from other organisms. Comparison of AaSdhB full sequences from sensitive and resistant isolates revealed that a highly conserved histidine residue (codon CAC in sensitive isolates) was converted to either tyrosine (codon TAC, type I mutants) or arginine (codon CGC, type II mutants) at position 277. In other fungal species this residue is involved in carboxamide resistance. In this study, 10 and 5 mutants were of type I and type II respectively, while 23 other resistant isolates (type III mutants) had no mutation in the histidine codon. The point mutation detected in type I mutants was used to design a pair of allele-specific polymerase chain reaction (PCR) primers to facilitate rapid detection. A PCR-restriction fragment length polymorphism (RFLP) assay in which amplified gene fragments were digested with AciI was successfully employed for the diagnosis of type II mutants. The relevance of these modifications in A. alternata AaSdhB sequence in conferring boscalid resistance is discussed.
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Affiliation(s)
- H F Avenot
- Department of Plant Pathology, University of California Davis, Kearney Agricultural Center, Parlier 93648, USA.
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Hogues H, Lavoie H, Sellam A, Mangos M, Roemer T, Purisima E, Nantel A, Whiteway M. Transcription factor substitution during the evolution of fungal ribosome regulation. Mol Cell 2008; 29:552-62. [PMID: 18342603 DOI: 10.1016/j.molcel.2008.02.006] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Revised: 01/15/2008] [Accepted: 02/04/2008] [Indexed: 01/10/2023]
Abstract
Coordinated ribosomal protein (RP) gene expression is crucial for cellular viability, but the transcriptional network controlling this regulon has only been well characterized in the yeast Saccharomyces cerevisiae. We have used whole-genome transcriptional and location profiling to establish that, in Candida albicans, the RP regulon is controlled by the Myb domain protein Tbf1 working in conjunction with Cbf1. These two factors bind both the promoters of RP genes and the rDNA locus; Tbf1 activates transcription at these loci and is essential. Orthologs of Tbf1 bind TTAGGG telomeric repeats in most eukaryotes, and TTAGGG cis-elements are present upstream of RP genes in plants and fungi, suggesting that Tbf1 was involved in both functions in ancestral eukaryotes. In all Hemiascomycetes, Rap1 substituted Tbf1 at telomeres and, in the S. cerevisiae lineage, this substitution also occurred independently at RP genes, illustrating the extreme adaptability and flexibility of transcriptional regulatory networks.
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Affiliation(s)
- Hervé Hogues
- Biotechnology Research Institute, National Research Council, Montreal, QC H4P 2R2, Canada
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Mesradi M, Elanique A, Nourreddine A, Pape A, Raiser D, Sellam A. Experimental characterization and Monte Carlo simulation of Si(Li) detector efficiency by radioactive sources and PIXE. Appl Radiat Isot 2008; 66:780-5. [PMID: 18397830 DOI: 10.1016/j.apradiso.2008.02.074] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
This work relates to the study and characterization of the response function of an X-ray spectrometry system. The intrinsic efficiency of a Si(Li) detector has been simulated with the Monte Carlo codes MCNP and GEANT4 in the photon energy range of 2.6-59.5keV. After finding it necessary to take a radiograph of the detector inside its cryostat to learn the correct dimensions, agreement within 10% between the simulations and experimental measurements with several point-like sources and PIXE results was obtained.
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Affiliation(s)
- M Mesradi
- Institut Pluridisciplinaire Hubert-Curien, UMR 7178 CNRS/IN2P3 et Université Louis Pasteur, Strasbourg Cedex 2, France
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