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Santos JM, Rao PN, Guerreiro A, Pinho L, Carret CK, Franke-Fayard BMD, Templeton TJ, Janse CJ, Mair GR. Plasmodium translationally repressed gene products are essential for parasite development and malaria transmission. Malar J 2012. [PMCID: PMC3472677 DOI: 10.1186/1475-2875-11-s1-p85] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
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Mwai L, Diriye A, Masseno V, Muriithi S, Feltwell T, Musyoki J, Lemieux J, Feller A, Mair GR, Marsh K, Newbold C, Nzila A, Carret CK. Genome wide adaptations of Plasmodium falciparum in response to lumefantrine selective drug pressure. PLoS One 2012; 7:e31623. [PMID: 22384044 PMCID: PMC3288012 DOI: 10.1371/journal.pone.0031623] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [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: 01/25/2011] [Accepted: 01/16/2012] [Indexed: 01/08/2023] Open
Abstract
The combination therapy of the Artemisinin-derivative Artemether (ART) with Lumefantrine (LM) (Coartem®) is an important malaria treatment regimen in many endemic countries. Resistance to Artemisinin has already been reported, and it is feared that LM resistance (LMR) could also evolve quickly. Therefore molecular markers which can be used to track Coartem® efficacy are urgently needed. Often, stable resistance arises from initial, unstable phenotypes that can be identified in vitro. Here we have used the Plasmodium falciparum multidrug resistant reference strain V1S to induce LMR in vitro by culturing the parasite under continuous drug pressure for 16 months. The initial IC50 (inhibitory concentration that kills 50% of the parasite population) was 24 nM. The resulting resistant strain V1SLM, obtained after culture for an estimated 166 cycles under LM pressure, grew steadily in 378 nM of LM, corresponding to 15 times the IC50 of the parental strain. However, after two weeks of culturing V1SLM in drug-free medium, the IC50 returned to that of the initial, parental strain V1S. This transient drug tolerance was associated with major changes in gene expression profiles: using the PFSANGER Affymetrix custom array, we identified 184 differentially expressed genes in V1SLM. Among those are 18 known and putative transporters including the multidrug resistance gene 1 (pfmdr1), the multidrug resistance associated protein and the V-type H+ pumping pyrophosphatase 2 (pfvp2) as well as genes associated with fatty acid metabolism. In addition we detected a clear selective advantage provided by two genomic loci in parasites grown under LM drug pressure, suggesting that all, or some of those genes contribute to development of LM tolerance – they may prove useful as molecular markers to monitor P. falciparum LM susceptibility.
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Affiliation(s)
- Leah Mwai
- Kenya Medical Research Institute, Welcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Abdi Diriye
- Kenya Medical Research Institute, Welcome Trust Research Programme, Kilifi, Kenya
| | - Victor Masseno
- Kenya Medical Research Institute, Welcome Trust Research Programme, Kilifi, Kenya
| | - Steven Muriithi
- Kenya Medical Research Institute, Welcome Trust Research Programme, Kilifi, Kenya
| | - Theresa Feltwell
- Pathogen Microarrays group, The Welcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Jennifer Musyoki
- Kenya Medical Research Institute, Welcome Trust Research Programme, Kilifi, Kenya
| | - Jacob Lemieux
- Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Avi Feller
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Gunnar R. Mair
- Molecular Parasitology Unit, Instituto de Medicina Molecular, Lisboa, Portugal
| | - Kevin Marsh
- Kenya Medical Research Institute, Welcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Chris Newbold
- Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Alexis Nzila
- Kenya Medical Research Institute, Welcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Céline K. Carret
- Molecular Parasitology Unit, Instituto de Medicina Molecular, Lisboa, Portugal
- * E-mail:
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Gomes-Santos CSS, Braks JAM, Prudêncio M, Carret CK, Gomes AR, Pain A, Feltwell T, Khan SM, Waters AP, Janse CJ, Mair GR, Mota MM. Developmental transition of Plasmodium sporozoites into liver-stage forms is regulated by the RNA binding protein Pumilio 2. Malar J 2010. [PMCID: PMC2963252 DOI: 10.1186/1475-2875-9-s2-p13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Mair GR, Lasonder E, Garver LS, Franke-Fayard BMD, Carret CK, Wiegant JCAG, Dirks RW, Dimopoulos G, Janse CJ, Waters AP. Universal features of post-transcriptional gene regulation are critical for Plasmodium zygote development. PLoS Pathog 2010; 6:e1000767. [PMID: 20169188 PMCID: PMC2820534 DOI: 10.1371/journal.ppat.1000767] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 01/13/2010] [Indexed: 01/21/2023] Open
Abstract
A universal feature of metazoan sexual development is the generation of oocyte P granules that withhold certain mRNA species from translation to provide coding potential for proteins during early post-fertilization development. Stabilisation of translationally quiescent mRNA pools in female Plasmodium gametocytes depends on the RNA helicase DOZI, but the molecular machinery involved in the silencing of transcripts in these protozoans is unknown. Using affinity purification coupled with mass-spectrometric analysis we identify a messenger ribonucleoprotein (mRNP) from Plasmodium berghei gametocytes defined by DOZI and the Sm-like factor CITH (homolog of worm CAR-I and fly Trailer Hitch). This mRNP includes 16 major factors, including proteins with homologies to components of metazoan P granules and archaeal proteins. Containing translationally silent transcripts, this mRNP integrates eIF4E and poly(A)-binding protein but excludes P body RNA degradation factors and translation-initiation promoting eIF4G. Gene deletion mutants of 2 core components of this mRNP (DOZI and CITH) are fertilization-competent, but zygotes fail to develop into ookinetes in a female gametocyte-mutant fashion. Through RNA-immunoprecipitation and global expression profiling of CITH-KO mutants we highlight CITH as a crucial repressor of maternally supplied mRNAs. Our data define Plasmodium P granules as an ancient mRNP whose protein core has remained evolutionarily conserved from single-cell organisms to germ cells of multi-cellular animals and stores translationally silent mRNAs that are critical for early post-fertilization development during the initial stages of mosquito infection. Therefore, translational repression may offer avenues as a target for the generation of transmission blocking strategies and contribute to limiting the spread of malaria. Transmission of malaria relies on ingestion of male and female sexual precursor cells (gametocytes) from the human host by the mosquito vector. Fertilization results in the formation of a diploid zygote that transforms into the ookinete, the motile form of the parasite that is capable of escaping the hostile mosquito midgut environment and truly infecting the mosquito vector. The developmental program of the Plasmodium zygote depends on the availability of mRNA pools transcribed and stored, but not translated, in the female gametocyte. Here we identify the core protein factors that co-operate in the assembly of mRNAs into a translationally silent ribonucleoprotein complex. In the absence of either DOZI or CITH—two key molecules within this complex—gametocytes suffer large scale mRNA de-stabilization that does not affect fertilization but culminates in the abortion of ookinete development soon after zygote formation. We characterize large scale, evolutionarily ancient translational silencing as a principal regulatory element during Plasmodium sexual development.
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Affiliation(s)
- Gunnar R. Mair
- Leiden Malaria Research Group, Department of Parasitology, Centre for Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
- Instituto de Medicina Molecular, Unidade de Parasitologia Molecular, Lisboa, Portugal
- * E-mail: (GRM); (APW)
| | - Edwin Lasonder
- Centre for Molecular and Biomolecular Informatics, NCMLS, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Lindsey S. Garver
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Blandine M. D. Franke-Fayard
- Leiden Malaria Research Group, Department of Parasitology, Centre for Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Céline K. Carret
- Instituto de Medicina Molecular, Unidade de Parasitologia Molecular, Lisboa, Portugal
| | - Joop C. A. G. Wiegant
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Roeland W. Dirks
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Chris J. Janse
- Leiden Malaria Research Group, Department of Parasitology, Centre for Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Andrew P. Waters
- Leiden Malaria Research Group, Department of Parasitology, Centre for Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
- Division of Infection and Immunity, Faculty of Biomedical Life Sciences, and Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, Scotland, United Kingdom
- * E-mail: (GRM); (APW)
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Tonkin CJ, Carret CK, Duraisingh MT, Voss TS, Ralph SA, Hommel M, Duffy MF, da Silva LM, Scherf A, Ivens A, Speed TP, Beeson JG, Cowman AF. Sir2 paralogues cooperate to regulate virulence genes and antigenic variation in Plasmodium falciparum. PLoS Biol 2009; 7:e84. [PMID: 19402747 PMCID: PMC2672602 DOI: 10.1371/journal.pbio.1000084] [Citation(s) in RCA: 191] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Accepted: 03/02/2009] [Indexed: 11/19/2022] Open
Abstract
Cytoadherance of Plasmodium falciparum-infected erythrocytes in the brain, organs and peripheral microvasculature is linked to morbidity and mortality associated with severe malaria. Parasite-derived P. falciparum Erythrocyte Membrane Protein 1 (PfEMP1) molecules displayed on the erythrocyte surface are responsible for cytoadherance and undergo antigenic variation in the course of an infection. Antigenic variation of PfEMP1 is achieved by in situ switching and mutually exclusive transcription of the var gene family, a process that is controlled by epigenetic mechanisms. Here we report characterisation of the P. falciparum silent information regulator's A and B (PfSir2A and PfSir2B) and their involvement in mutual exclusion and silencing of the var gene repertoire. Analysis of P. falciparum parasites lacking either PfSir2A or PfSir2B shows that these NAD+-dependent histone deacetylases are required for silencing of different var gene subsets classified by their conserved promoter type. We also demonstrate that in the absence of either of these molecules mutually exclusive expression of var genes breaks down. We show that var gene silencing originates within the promoter and PfSir2 paralogues are involved in cis spreading of silenced chromatin into adjacent regions. Furthermore, parasites lacking PfSir2A but not PfSir2B have considerably longer telomeric repeats, demonstrating a role for this molecule in telomeric end protection. This work highlights the pivotal but distinct role for both PfSir2 paralogues in epigenetic silencing of P. falciparum virulence genes and the control of pathogenicity of malaria infection. The unicellular parasite Plasmodium falciparum is the cause of the most severe form of malaria and is responsible for 300 million infections and ∼2 million deaths a year. Infected erythrocytes clump and block capillaries in the peripheral circulation, the brain, and placenta and are a major contributor to the pathology of malaria. A parasite-derived protein displayed on the surface of the infected erythrocyte is responsible for erythrocyte clumping in capillaries. Although 60 subtelomeric var genes can encode different versions of this “sticky” capillary-binding protein, only one protein is expressed at a time, and switches in expression between these genes causes variation of this pathogenic molecule enabling the parasite to evade the immune system. Here we identify two chromatin-modifying proteins that cooperate to mediate silencing and mutual exclusive expression of var genes. These proteins are thus important virulence factors of the malaria-causing parasite. Investigation into two Sir2 histone deacetylases in the malaria-causing parasite revealstrans-acting epigenetic factors control mutually exclusive expression of a major subtelomeric virulence gene family.
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Affiliation(s)
| | - Céline K Carret
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Manoj T Duraisingh
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Till S Voss
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Stuart A Ralph
- Department of Biochemistry, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Mirja Hommel
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Michael F Duffy
- Department of Medicine RMH/WH, The University of Melbourne, Melbourne, Australia
| | | | - Artur Scherf
- Unité de Biologie des Interactions Hôte-Parasite, Institut Pasteur and CNRS, Paris, France
| | - Alasdair Ivens
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Terence P Speed
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - James G Beeson
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia
- * To whom correspondence should be addressed. E-mail:
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McNeill L, Salmond RJ, Cooper JC, Carret CK, Cassady-Cain RL, Roche-Molina M, Tandon P, Holmes N, Alexander DR. The differential regulation of Lck kinase phosphorylation sites by CD45 is critical for T cell receptor signaling responses. Immunity 2007; 27:425-37. [PMID: 17719247 DOI: 10.1016/j.immuni.2007.07.015] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2006] [Revised: 05/20/2007] [Accepted: 07/03/2007] [Indexed: 01/27/2023]
Abstract
The molecular mechanisms whereby the CD45 tyrosine phosphatase (PTPase) regulates T cell receptor (TCR) signaling responses remain to be elucidated. To investigate this question, we have reconstituted CD45 (encoded by Ptprc)-deficient mice, which display severe defects in thymic development, with five different expression levels of transgenic CD45RO, or with mutant PTPase null or PTPase-low CD45R0. Whereas CD45 PTPase activity was absolutely required for the reconstitution of thymic development, only 3% of wild-type CD45 activity restored T cell numbers and normal cytotoxic T cell responses. Lowering the CD45 expression increased CD4 lineage commitment. Peripheral T cells with very low activity of CD45 phosphatase displayed reduced TCR signaling, whereas intermediate activity caused hyperactivation of CD4+ and CD8+ T cells. These results are explained by a rheostat mechanism whereby CD45 differentially regulates the negatively acting pTyr-505 and positively acting pTyr-394 p56(lck) tyrosine kinase phosphorylation sites. We propose that high wild-type CD45 expression is necessary to dephosphorylate p56(lck) pTyr-394, suppressing CD4 T+ cell lineage commitment and hyperactivity.
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Affiliation(s)
- Louise McNeill
- Laboratory of Lymphocyte Signalling and Development, The Babraham Institute, Babraham, Cambridge CB2 4AT, UK
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