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Singh S, Santos JM, Orchard LM, Yamada N, van Biljon R, Painter HJ, Mahony S, Llinás M. The PfAP2-G2 transcription factor is a critical regulator of gametocyte maturation. Mol Microbiol 2021; 115:1005-1024. [PMID: 33368818 PMCID: PMC8330521 DOI: 10.1111/mmi.14676] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 12/14/2022]
Abstract
Differentiation from asexual blood stages to mature sexual gametocytes is required for the transmission of malaria parasites. Here, we report that the ApiAP2 transcription factor, PfAP2-G2 (PF3D7_1408200) plays a critical role in the maturation of Plasmodium falciparum gametocytes. PfAP2-G2 binds to the promoters of a wide array of genes that are expressed at many stages of the parasite life cycle. Interestingly, we also find binding of PfAP2-G2 within the gene body of almost 3,000 genes, which strongly correlates with the location of H3K36me3 and several other histone modifications as well as Heterochromatin Protein 1 (HP1), suggesting that occupancy of PfAP2-G2 in gene bodies may serve as an alternative regulatory mechanism. Disruption of pfap2-g2 does not impact asexual development, but the majority of sexual parasites are unable to mature beyond stage III gametocytes. The absence of pfap2-g2 leads to overexpression of 28% of the genes bound by PfAP2-G2 and none of the PfAP2-G2 bound genes are downregulated, suggesting that it is a repressor. We also find that PfAP2-G2 interacts with chromatin remodeling proteins, a microrchidia (MORC) protein, and another ApiAP2 protein (PF3D7_1139300). Overall our data demonstrate that PfAP2-G2 establishes an essential gametocyte maturation program in association with other chromatin-related proteins.
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Affiliation(s)
- Suprita Singh
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, USA 16802
| | - Joana M. Santos
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, USA 16802
| | - Lindsey M. Orchard
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, USA 16802
| | - Naomi Yamada
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA 16802
| | - Riëtte van Biljon
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, USA 16802
| | - Heather J. Painter
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, USA 16802
| | - Shaun Mahony
- Center for Eukaryotic Gene Regulation, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802
| | - Manuel Llinás
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, USA 16802
- Center for Eukaryotic Gene Regulation, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA 16802
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2
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Prajapati SK, Ayanful-Torgby R, Pava Z, Barbeau MC, Acquah FK, Cudjoe E, Kakaney C, Amponsah JA, Obboh E, Ahmed AE, Abuaku BK, McCarthy JS, Amoah LE, Williamson KC. The transcriptome of circulating sexually committed Plasmodium falciparum ring stage parasites forecasts malaria transmission potential. Nat Commun 2020; 11:6159. [PMID: 33268801 PMCID: PMC7710746 DOI: 10.1038/s41467-020-19988-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 10/06/2020] [Indexed: 11/30/2022] Open
Abstract
Malaria is spread by the transmission of sexual stage parasites, called gametocytes. However, with Plasmodium falciparum, gametocytes can only be detected in peripheral blood when they are mature and transmissible to a mosquito, which complicates control efforts. Here, we identify the set of genes overexpressed in patient blood samples with high levels of gametocyte-committed ring stage parasites. Expression of all 18 genes is regulated by transcription factor AP2-G, which is required for gametocytogenesis. We select three genes, not expressed in mature gametocytes, to develop as biomarkers. All three biomarkers we validate in vitro using 6 different parasite lines and develop an algorithm that predicts gametocyte production in ex vivo samples and volunteer infection studies. The biomarkers are also sensitive enough to monitor gametocyte production in asymptomatic P. falciparum carriers allowing early detection and treatment of infectious reservoirs, as well as the in vivo analysis of factors that modulate sexual conversion. Malaria gametocytes are sexual-stage parasites transmitted from mammalian host’s blood back to their insect vector. Here, Prajapati et al. identify gametocyte-committed ring-stage biomarkers allowing to forecast malaria transmission potential.
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Affiliation(s)
- Surendra K Prajapati
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
| | - Ruth Ayanful-Torgby
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Zuleima Pava
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Michelle C Barbeau
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.,University of Virginia, Charlottesville, VA, USA
| | - Festus K Acquah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Elizabeth Cudjoe
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Courage Kakaney
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Jones A Amponsah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | | | - Anwar E Ahmed
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Benjamin K Abuaku
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Linda E Amoah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Kim C Williamson
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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3
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Ararat-Sarria M, Prado CC, Camargo M, Ospina LT, Camargo PA, Curtidor H, Patarroyo MA. Sexual forms obtained in a continuous in vitro cultured Colombian strain of Plasmodium falciparum (FCB2). Malar J 2020; 19:57. [PMID: 32014000 PMCID: PMC6998264 DOI: 10.1186/s12936-020-3142-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 01/25/2020] [Indexed: 12/03/2022] Open
Abstract
Background The epidemiological control of malaria has been hampered by the appearance of parasite resistance to anti-malarial drugs and by the resistance of mosquito vectors to control measures. This has also been associated with weak transmission control, mostly due to poor control of asymptomatic patients associated with host-vector transmission. This highlights the importance of studying the parasite’s sexual forms (gametocytes) which are involved in this phase of the parasite’s life-cycle. Some African and Asian strains of Plasmodium falciparum have been fully characterized regarding sexual forms’ production; however, few Latin-American strains have been so characterized. This study was aimed at characterizing the Colombian FCB2 strain as a gametocyte producer able to infect mosquitoes. Methods Gametocyte production was induced in in vitro cultured P. falciparum FCB2 and 3D7 strains. Pfap2g and Pfs25 gene expression was detected in FCB2 strain gametocyte culture by RT-PCR. Comparative analysis of gametocytes obtained from both strains was made (counts and morphological changes). In vitro zygote formation from FCB2 gametocytes was induced by incubating a gametocyte culture sample at 27 °C for 20 min. A controlled Anopheles albimanus infection was made using an artificial feed system with cultured FCB2 gametocytes (14–15 days old). Mosquito midgut dissection was then carried out for analyzing oocysts. Results The FCB2 strain expressed Pfap2g, Pfs16, Pfg27/25 and Pfs25 sexual differentiation-related genes after in vitro sexual differentiation induction, producing gametocytes that conserved the expected morphological features. The amount of FCB2 gametocytes produced was similar to that from the 3D7 strain. FCB2 gametocytes were differentiated into zygotes and ookinetes after an in vitro low-temperature stimulus and infected An. albimanus mosquitoes, developing to oocyst stage. Conclusions Even with the history of long-term FCB2 strain in vitro culture maintenance, it has retained its sexual differentiation ability. The gametocytes produced here preserved these parasite forms’ usual characteristics and An. albimanus infection capability, thus enabling its use as a tool for studying sexual form biology, An. albimanus infection comparative analysis and anti-malarial drug and vaccine development.
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Affiliation(s)
- Monica Ararat-Sarria
- Receptor-Ligand Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia.,PhD Programme in Biomedical and Biological Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Cesar Camilo Prado
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
| | - Milena Camargo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
| | - Laura Tatiana Ospina
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
| | - Paola Andrea Camargo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia
| | - Hernando Curtidor
- Receptor-Ligand Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia.,Animal Science Faculty, Universidad de Ciencias Aplicadas y Ambientales (U.D.C.A), Bogotá, Colombia
| | - Manuel Alfonso Patarroyo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá, Colombia. .,School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia.
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4
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Filarsky M, Fraschka SA, Niederwieser I, Brancucci NMB, Carrington E, Carrió E, Moes S, Jenoe P, Bártfai R, Voss TS. GDV1 induces sexual commitment of malaria parasites by antagonizing HP1-dependent gene silencing. Science 2018; 359:1259-1263. [PMID: 29590075 DOI: 10.1126/science.aan6042] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 01/17/2018] [Indexed: 11/02/2022]
Abstract
Malaria is caused by Plasmodium parasites that proliferate in the bloodstream. During each replication cycle, some parasites differentiate into gametocytes, the only forms able to infect the mosquito vector and transmit malaria. Sexual commitment is triggered by activation of AP2-G, the master transcriptional regulator of gametocytogenesis. Heterochromatin protein 1 (HP1)-dependent silencing of ap2-g prevents sexual conversion in proliferating parasites. In this study, we identified Plasmodium falciparum gametocyte development 1 (GDV1) as an upstream activator of sexual commitment. We found that GDV1 targeted heterochromatin and triggered HP1 eviction, thus derepressing ap2-g Expression of GDV1 was responsive to environmental triggers of sexual conversion and controlled via a gdv1 antisense RNA. Hence, GDV1 appears to act as an effector protein that induces sexual differentiation by antagonizing HP1-dependent gene silencing.
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Affiliation(s)
- Michael Filarsky
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland.,University of Basel, 4003 Basel, Switzerland
| | - Sabine A Fraschka
- Department of Molecular Biology, Radboud University, 6525 GA Nijmegen, Netherlands
| | - Igor Niederwieser
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland.,University of Basel, 4003 Basel, Switzerland
| | - Nicolas M B Brancucci
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland.,University of Basel, 4003 Basel, Switzerland
| | - Eilidh Carrington
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland.,University of Basel, 4003 Basel, Switzerland
| | - Elvira Carrió
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland.,University of Basel, 4003 Basel, Switzerland
| | - Suzette Moes
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Paul Jenoe
- Biozentrum, University of Basel, 4056 Basel, Switzerland
| | - Richárd Bártfai
- Department of Molecular Biology, Radboud University, 6525 GA Nijmegen, Netherlands
| | - Till S Voss
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland. .,University of Basel, 4003 Basel, Switzerland
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5
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Messina V, Valtieri M, Rubio M, Falchi M, Mancini F, Mayor A, Alano P, Silvestrini F. Gametocytes of the Malaria Parasite Plasmodium falciparum Interact With and Stimulate Bone Marrow Mesenchymal Cells to Secrete Angiogenetic Factors. Front Cell Infect Microbiol 2018; 8:50. [PMID: 29546035 PMCID: PMC5838020 DOI: 10.3389/fcimb.2018.00050] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 02/09/2018] [Indexed: 12/31/2022] Open
Abstract
The gametocytes of Plasmodium falciparum, responsible for the transmission of this malaria parasite from humans to mosquitoes, accumulate and mature preferentially in the human bone marrow. In the 10 day long sexual development of P. falciparum, the immature gametocytes reach and localize in the extravascular compartment of this organ, in contact with several bone marrow stroma cell types, prior to traversing the endothelial lining and re-entering in circulation at maturity. To investigate the host parasite interplay underlying this still obscure process, we developed an in vitro tridimensional co-culture system in a Matrigel scaffold with P. falciparum gametocytes and self-assembling spheroids of human bone marrow mesenchymal cells (hBM-MSCs). Here we show that this co-culture system sustains the full maturation of the gametocytes and that the immature, but not the mature, gametocytes adhere to hBM-MSCs via trypsin-sensitive parasite ligands exposed on the erythrocyte surface. Analysis of a time course of gametocytogenesis in the co-culture system revealed that gametocyte maturation is accompanied by the parasite induced stimulation of hBM-MSCs to secrete a panel of 14 cytokines and growth factors, 13 of which have been described to play a role in angiogenesis. Functional in vitro assays on human bone marrow endothelial cells showed that supernatants from the gametocyte mesenchymal cell co-culture system enhance ability of endothelial cells to form vascular tubes. These results altogether suggest that the interplay between immature gametocytes and hBM-MSCs may induce functional and structural alterations in the endothelial lining of the human bone marrow hosting the P. falciparum transmission stages.
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Affiliation(s)
- Valeria Messina
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy
| | - Mauro Valtieri
- Dipartimento di Oncologia e Medicina Molecolare, Istituto Superiore di Sanità, Rome, Italy
| | - Mercedes Rubio
- ISGlobal, Barcelona Ctr. Int. Health Res, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Mario Falchi
- AIDS National Center, Istituto Superiore di Sanità, Rome, Italy
| | - Francesca Mancini
- Dipartimento di Biotecnologie Cellulari ed Ematologia, Umberto I - Policlinico di Roma, Rome, Italy
| | - Alfredo Mayor
- ISGlobal, Barcelona Ctr. Int. Health Res, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde da Manhiça, Maputo, Mozambique
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy
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6
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Ortega C, Frando A, Webb-Robertson BJ, Anderson LN, Fleck N, Flannery EL, Fishbaugher M, Murphree TA, Hansen JR, Smith RD, Kappe SHI, Wright AT, Grundner C. A Global Survey of ATPase Activity in Plasmodium falciparum Asexual Blood Stages and Gametocytes. Mol Cell Proteomics 2017; 17:111-120. [PMID: 29079720 DOI: 10.1074/mcp.ra117.000088] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 10/03/2017] [Indexed: 01/12/2023] Open
Abstract
Effective malaria control and elimination in hyperendemic areas of the world will require treatment of the Plasmodium falciparum (Pf) blood stage that causes disease as well as the gametocyte stage that is required for transmission from humans to the mosquito vector. Most currently used therapies do not kill gametocytes, a highly specialized, non-replicating sexual parasite stage. Further confounding next generation drug development against Pf is the unknown metabolic state of the gametocyte and the lack of known biochemical activity for most parasite gene products in general. Here, we take a systematic activity-based proteomics approach to survey the activity of the large and druggable ATPase family in replicating blood stage asexual parasites and transmissible, non-replicating sexual gametocytes. ATPase activity broadly changes during the transition from asexual schizonts to sexual gametocytes, indicating altered metabolism and regulatory roles of ATPases specific for each lifecycle stage. We further experimentally confirm existing annotation and predict ATPase function for 38 uncharacterized proteins. By mapping the activity of ATPases associated with gametocytogenesis, we assign biochemical activity to a large number of uncharacterized proteins and identify new candidate transmission blocking targets.
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Affiliation(s)
- Corrie Ortega
- From the ‡Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, Washington 98109
| | - Andrew Frando
- From the ‡Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, Washington 98109.,§Department of Global Health, University of Washington, Seattle, Washington 98195
| | - Bobbie-Jo Webb-Robertson
- ¶Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Lindsey N Anderson
- ¶Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Neil Fleck
- From the ‡Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, Washington 98109
| | - Erika L Flannery
- From the ‡Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, Washington 98109
| | - Matthew Fishbaugher
- From the ‡Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, Washington 98109
| | - Taylor A Murphree
- ¶Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Joshua R Hansen
- ¶Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Richard D Smith
- ¶Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Stefan H I Kappe
- From the ‡Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, Washington 98109.,§Department of Global Health, University of Washington, Seattle, Washington 98195
| | - Aaron T Wright
- ¶Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352
| | - Christoph Grundner
- From the ‡Center for Infectious Disease Research (formerly Seattle Biomedical Research Institute), Seattle, Washington 98109; .,§Department of Global Health, University of Washington, Seattle, Washington 98195
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7
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A humanized mouse model for sequestration of Plasmodium falciparum sexual stages and in vivo evaluation of gametocytidal drugs. Sci Rep 2016; 6:35025. [PMID: 27731362 PMCID: PMC5059736 DOI: 10.1038/srep35025] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 09/20/2016] [Indexed: 12/13/2022] Open
Abstract
The development of new drugs to disrupt malaria transmission requires the establishment of an in vivo model to address the biology of Plasmodium falciparum sexual stages (gametocytes). Herein we show that chemically immune-modulated NSG mice grafted with human erythrocytes support complete sexual development of P. falciparum parasites and generate high gametocytemia. Immunohistochemistry and RT-qPCR analyses indicate an enrichment of immature gametocytes in the bone marrow and the spleen, suggesting a sequestration mechanism reminiscent to that observed in humans. Upon primaquine treatment, elimination of gametocytes from peripheral blood and from sequestration sites was observed, providing a proof of concept that these mice can be used for testing drugs. Therefore, this model allows the investigation of P. falciparum sexual commitment, gametocyte interactions with the bone marrow and spleen and provides the missing link between current in vitro assays and Phase I trials in humans for testing new malaria gametocytidal drugs.
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8
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Tibúrcio M, Dixon MWA, Looker O, Younis SY, Tilley L, Alano P. Specific expression and export of the Plasmodium falciparum Gametocyte EXported Protein-5 marks the gametocyte ring stage. Malar J 2015; 14:334. [PMID: 26315106 PMCID: PMC4552133 DOI: 10.1186/s12936-015-0853-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 08/16/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium falciparum sexual development plays a fundamental role in the transmission and spread of malaria. The ability to generate gametocytes can be lost during culture in vitro, often associated with the loss of a subtelomeric region of chromosome 9. Gametocytogenesis starts with erythrocyte invasion by a sexually committed merozoite, but the first available specific marker of sexual differentiation appears only from 24 h post invasion. METHODS Specific antibodies and gene fusions were produced to study the timing of expression and the sub-cellular localization of the P. falciparum Gametocyte EXported Protein-5 (PfGEXP5), encoded in the subtelomeric region of chromosome 9. Expression patterns were examined in wild-type parasites and in parasite lines mutated in the Apetala2-G (AP2-G) transcription factor, governing a cascade of early sexual stage specific genes. RESULTS PfGEXP5 is highly expressed in early sexual stages and it is actively exported to the infected erythrocyte cytoplasm from as early as 14 h post-invasion in haemozoin-free, ring stage-like parasites. The pattern of PfGEXP5 expression and export is similar in wild-type parasites and in independent AP2-G defective parasite lines unable to produce gametocytes. CONCLUSIONS PfGEXP5 represents the earliest post-invasion sexual stage marker described to date. This provides a tool that can be used to identify sexually committed ring stage parasites in natural infections. This early gametocyte marker would enable the identification and mapping of malaria transmission reservoirs in human populations and the study of gametocyte sequestration dynamics in infected individuals. The fact that regulation of PfGEXP5 does not depend on the AP2-G master regulator of parasite sexual development suggests that, after sexual commitment, differentiation progresses through multiple checkpoints in the early phase of gametocytogenesis.
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Affiliation(s)
- Marta Tibúrcio
- Dipartimento di Malattie Infettive, Parassitarie e Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy. .,The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London, NW7 1AA, UK.
| | - Matthew W A Dixon
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia.
| | - Oliver Looker
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia.
| | - Sumera Younis Younis
- Dipartimento di Malattie Infettive, Parassitarie e Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy. .,Department of Parasitology, Biomedical Primate Research Centre, PO Box 306, 2280 GH, Rijswijk, The Netherlands.
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia.
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie e Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161, Rome, Italy.
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9
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Josling GA, Llinás M. Sexual development in Plasmodium parasites: knowing when it's time to commit. Nat Rev Microbiol 2015; 13:573-87. [DOI: 10.1038/nrmicro3519] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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10
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Brancucci NMB, Bertschi NL, Zhu L, Niederwieser I, Chin WH, Wampfler R, Freymond C, Rottmann M, Felger I, Bozdech Z, Voss TS. Heterochromatin protein 1 secures survival and transmission of malaria parasites. Cell Host Microbe 2015; 16:165-176. [PMID: 25121746 DOI: 10.1016/j.chom.2014.07.004] [Citation(s) in RCA: 186] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 04/28/2014] [Accepted: 06/06/2014] [Indexed: 12/14/2022]
Abstract
Clonally variant expression of surface antigens allows the malaria parasite Plasmodium falciparum to evade immune recognition during blood stage infection and secure malaria transmission. We demonstrate that heterochromatin protein 1 (HP1), an evolutionary conserved regulator of heritable gene silencing, controls expression of numerous P. falciparum virulence genes as well as differentiation into the sexual forms that transmit to mosquitoes. Conditional depletion of P. falciparum HP1 (PfHP1) prevents mitotic proliferation of blood stage parasites and disrupts mutually exclusive expression and antigenic variation of the major virulence factor PfEMP1. Additionally, PfHP1-dependent regulation of PfAP2-G, a transcription factor required for gametocyte conversion, controls the switch from asexual proliferation to sexual differentiation, providing insight into the epigenetic mechanisms underlying gametocyte commitment. These findings show that PfHP1 is centrally involved in clonally variant gene expression and sexual differentiation in P. falciparum and have major implications for developing antidisease and transmission-blocking interventions against malaria.
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Affiliation(s)
- Nicolas M B Brancucci
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4051, Switzerland; University of Basel, Petersplatz 1, Basel 4003, Switzerland
| | - Nicole L Bertschi
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4051, Switzerland; University of Basel, Petersplatz 1, Basel 4003, Switzerland
| | - Lei Zhu
- School of Biological Sciences, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Igor Niederwieser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4051, Switzerland; University of Basel, Petersplatz 1, Basel 4003, Switzerland
| | - Wai Hoe Chin
- School of Biological Sciences, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Rahel Wampfler
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4051, Switzerland; University of Basel, Petersplatz 1, Basel 4003, Switzerland
| | - Céline Freymond
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4051, Switzerland; University of Basel, Petersplatz 1, Basel 4003, Switzerland
| | - Matthias Rottmann
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4051, Switzerland; University of Basel, Petersplatz 1, Basel 4003, Switzerland
| | - Ingrid Felger
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4051, Switzerland; University of Basel, Petersplatz 1, Basel 4003, Switzerland
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Till S Voss
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Socinstrasse 57, Basel 4051, Switzerland; University of Basel, Petersplatz 1, Basel 4003, Switzerland.
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11
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Eksi S, Morahan BJ, Haile Y, Furuya T, Jiang H, Ali O, Xu H, Kiattibutr K, Suri A, Czesny B, Adeyemo A, Myers TG, Sattabongkot J, Su XZ, Williamson KC. Plasmodium falciparum gametocyte development 1 (Pfgdv1) and gametocytogenesis early gene identification and commitment to sexual development. PLoS Pathog 2012; 8:e1002964. [PMID: 23093935 PMCID: PMC3475683 DOI: 10.1371/journal.ppat.1002964] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/27/2012] [Indexed: 12/13/2022] Open
Abstract
Malaria transmission requires the production of male and female gametocytes in the human host followed by fertilization and sporogonic development in the mosquito midgut. Although essential for the spread of malaria through the population, little is known about the initiation of gametocytogenesis in vitro or in vivo. Using a gametocyte-defective parasite line and genetic complementation, we show that Plasmodium falciparumgametocyte development 1 gene (Pfgdv1), encoding a peri-nuclear protein, is critical for early sexual differentiation. Transcriptional analysis of Pfgdv1 negative and positive parasite lines identified a set of gametocytogenesis early genes (Pfge) that were significantly down-regulated (>10 fold) in the absence of Pfgdv1 and expression was restored after Pfgdv1 complementation. Progressive accumulation of Pfge transcripts during successive rounds of asexual replication in synchronized cultures suggests that gametocytes are induced continuously during asexual growth. Comparison of Pfge gene transcriptional profiles in patient samples divided the genes into two groups differing in their expression in mature circulating gametocytes and providing candidates to evaluate gametocyte induction and maturation separately in vivo. The expression profile of one of the early gametocyte specific genes, Pfge1, correlated significantly with asexual parasitemia, which is consistent with the ongoing induction of gametocytogenesis during asexual growth observed in vitro and reinforces the need for sustained transmission-blocking strategies to eliminate malaria. As malaria control efforts move toward eradication it becomes increasingly important to develop interventions that block transmission. Consequently, advances are needed in our understanding of the production of gametocytes, which are required to transmit the disease. This report provides a first view of the initial stages of gametocytogenesis in vitro and in vivo and demonstrates that during each asexual replication cycle a subpopulation of parasites convert to gametocyte development providing a long transmission window. We also identify a gene that is critical for gametocyte production, P. falciparumgametocyte development 1 (Pfgdv1) and a set of genes specifically expressed during early gametocytogenesis in P. falciparum (Pfge genes). The expression profile and peri-nuclear location of Pfgdv1 in a subpopulation of schizonts is consistent with a role in an early step in gametocytogenesis. The RNA levels of Pfgdv1 and the Pfge genes accumulated gradually over several asexual cycles in vitro suggesting ongoing gametocyte formation during asexual growth. The further evaluation of these genes in a cohort of malaria infected patients indicated they are good candidates for markers to distinguish ring stage parasites committed to gametocyte production from circulating mature gametocytes, allowing direct analysis of the initiation of sexual differentiation in vivo.
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Affiliation(s)
- Saliha Eksi
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Belinda J. Morahan
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yoseph Haile
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Tetsuya Furuya
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Hongying Jiang
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Omar Ali
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Huichun Xu
- Center for Research on Genomics and Global Health, Inherited Disease Research Branch, National Human Genomics Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kirakorn Kiattibutr
- Department of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Amreena Suri
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Beata Czesny
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Adebowale Adeyemo
- Center for Research on Genomics and Global Health, Inherited Disease Research Branch, National Human Genomics Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Timothy G. Myers
- Genomic Technologies Section, Research Technologies Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jetsumon Sattabongkot
- Department of Entomology, U.S. Army Medical Component, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Xin-zhuan Su
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kim C. Williamson
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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12
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Hanssen E, Knoechel C, Dearnley M, Dixon MW, Le Gros M, Larabell C, Tilley L. Soft X-ray microscopy analysis of cell volume and hemoglobin content in erythrocytes infected with asexual and sexual stages of Plasmodium falciparum. J Struct Biol 2012; 177:224-32. [DOI: 10.1016/j.jsb.2011.09.003] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 09/05/2011] [Accepted: 09/09/2011] [Indexed: 12/13/2022]
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13
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Miao J, Li J, Fan Q, Li X, Li X, Cui L. The Puf-family RNA-binding protein PfPuf2 regulates sexual development and sex differentiation in the malaria parasite Plasmodium falciparum. J Cell Sci 2010; 123:1039-49. [PMID: 20197405 DOI: 10.1242/jcs.059824] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Translation regulation plays an important role during gametocytogenesis in the malaria parasite, a process that is obligatory for the transmission of the parasite through mosquito vectors. In this study we determined the function of PfPuf2, a member of the Puf family of translational repressors, in gametocytogenesis of Plasmodium falciparum. Tagging of the endogenous PfPuf2 protein with green fluorescent protein showed that PfPuf2 was expressed in both male and female gametocytes, and the protein was localized in the cytoplasm of the parasite. Targeted disruption of the PfPuf2 gene did not affect asexual growth of the parasite, but promoted the formation of gametocytes and differentiation of male gametocytes. Complementation studies were performed to confirm that the resultant phenotypic changes were due to disruption of the PfPuf2 gene. Episomal expression of PfPuf2 under its cognate promoter almost restored the gametocytogenesis rate in a PfPuf2 disruptant to the level of the wild-type parasite. It also partially restored the effect of PfPuf2 disruption on male-female sex ratio. In addition, episomal overexpression of PfPuf2 under its cognate promoter but with a higher concentration of the selection drug or under the constitutive hsp86 promoter in both the PfPuf2-disruptant and wild-type 3D7 lines, further dramatically reduced gametocytogenesis rates and sex ratios. These findings suggest that in this early branch of eukaryotes the function of PfPuf2 is consistent with the ancestral function of suppressing differentiation proposed for Puf-family proteins.
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Affiliation(s)
- Jun Miao
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA
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14
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Gopalakrishnan AM, López-Estraño C. Role of cis-regulatory elements on the ring-specific hrp3 promoter in the human parasite Plasmodium falciparum. Parasitol Res 2010; 106:833-45. [PMID: 20127361 DOI: 10.1007/s00436-010-1738-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Accepted: 01/04/2010] [Indexed: 11/30/2022]
Abstract
Identification of promoter elements responsible for regulation of gene expression has been hampered by the AT richness of P. falciparum intergenic regions. Nested deletions of histidine-rich protein 3 (hrp3) promoter suggested the presence of a multipartite ring-specific element. Linker scanning (LS) of this ring-specific promoter showed that the alteration of several promoter regions decreased the luciferase activity compared to the wild-type configuration, indicating that these regions played a role in gene expression. No homology was observed by comparison of putative regulatory elements of other genes identified by bioinformatic analysis with the hrp3 enhancer, implying a different mechanism of gene regulation by the hrp3 promoter. LS and deletion analysis of the 5' untranslated region (UTR) of the hrp3 suggested that this region contains elements which interact with promoter elements to regulate gene expression. Analysis of the intron in the UTR region suggested that this region does not play a role in stage specificity in the hrp3 promoter. Together, our results indicate the presence of multiple mechanisms of gene regulation in the parasite.
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15
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Olivieri A, Camarda G, Bertuccini L, van de Vegte-Bolmer M, Luty AJF, Sauerwein R, Alano P. The Plasmodium falciparum protein Pfg27 is dispensable for gametocyte and gamete production, but contributes to cell integrity during gametocytogenesis. Mol Microbiol 2009; 73:180-93. [PMID: 19570101 DOI: 10.1111/j.1365-2958.2009.06762.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In the human malaria parasite Plasmodium falciparum, gametocyte maturation is a process remarkably longer than in other malaria species, accompanied by expression of 2-300 sexual stage-specific proteins. Disruption of several of their encoding genes so far showed that only the abundant protein Pfg27, produced at the onset of sexual differentiation, is essential for gametocyte production. In contrast with what has been previously described, here we show that P. falciparum pfg27 disruptant lines are able to undergo all stages of gametocyte maturation, and are able to mature into gametes. A fraction of Pfg27-defective gametocytes show, however, distinct abnormalities in intra- and extra-cellular membranous compartments, such as accumulation of parasitophorous vacuole-derived vesicles in the erythrocyte cytoplasm, large intracellular vacuoles and discontinuities in their trilaminar cell membrane. This work revises current knowledge on the role of Pfg27, indicating that the protein is not required for parasite entry into sexual differentiation, and suggesting that it is instead involved in maintaining cell integrity in the uniquely long gametocytogenesis of P. falciparum.
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Affiliation(s)
- Anna Olivieri
- Dipartimento di Malattie Infettive, Parassitarie e Immunomediate, Istituto Superiore di Sanità, 00161, Rome, Italy
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16
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Petter M, Bonow I, Klinkert MQ. Diverse expression patterns of subgroups of the rif multigene family during Plasmodium falciparum gametocytogenesis. PLoS One 2008; 3:e3779. [PMID: 19020666 PMCID: PMC2582490 DOI: 10.1371/journal.pone.0003779] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Accepted: 11/02/2008] [Indexed: 12/14/2022] Open
Abstract
Background The maturation of Plasmodium falciparum gametocytes in the human host takes several days, during which the parasites need to efficiently evade the host immune system. Like asexual stage parasites, immature gametocytes can sequester at various sites in the human body, and only mature sexual stages are found in the circulation. Although the fundamental mechanisms of gametocyte immune evasion are still largely unknown, candidate molecules that may be involved include variant antigens encoded by multigene families in the P. falciparum genome, such as the PfEMP1, STEVOR and RIFIN proteins. While expression of the former two families in sexual stages has been investigated earlier, we report here RIFIN expression during gametocytogenesis. Methodology/Principal Findings Variants of two previously characterized RIFIN subfamilies (A- and B-type RIFINs) were found to be synthesized in gametocytes. Immunofluorescence experiments showed A-type RIFINs to be accumulated in a crescent-shaped pattern of discrete punctate structures at the infected erythrocyte membrane, while members of the B-type family were associated with the parasite. Transcription analysis demonstrated the existence of diverse transcriptional regulation patterns during sexual differentiation and indicated variant-specific regulation of B-type RIFINs, in contrast to group-specific regulation for A-type RIFINs. Phylogenetic analysis of 5′-upstream regions showed that the rif–gene family falls into five defined clusters, designated rups (rifupstream) A1, A2, AB, B and C. In trophozoites and early gametocytes, rif variants of the rupsA2-type were preferentially expressed. Conclusions/Significance In this work we demonstrate the expression dynamics of the rif-gene family during sexual differentiation and present indications for subgroup specific regulation patterns. Therefore, our data provide a first foundation and point to new directions for future investigations of the potential role of RIFINs in gametocyte immune evasion.
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Affiliation(s)
- Michaela Petter
- Bernhard Nocht-Institute for Tropical Medicine, Hamburg, Germany.
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17
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Olivieri A, Silvestrini F, Sanchez M, Alano P. A 140-bp AT-rich sequence mediates positive and negative transcriptional control of a Plasmodium falciparum developmentally regulated promoter. Int J Parasitol 2008; 38:299-312. [DOI: 10.1016/j.ijpara.2007.08.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Revised: 08/14/2007] [Accepted: 08/15/2007] [Indexed: 11/26/2022]
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18
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Siddiqui AA, Singh N, Sharma YD. Expression and purification of a Plasmodium vivax antigen - PvTARAg55 tryptophan- and alanine-rich antigen and its immunological responses in human subjects. Vaccine 2007; 26:96-107. [PMID: 18054126 DOI: 10.1016/j.vaccine.2007.10.042] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 10/11/2007] [Accepted: 10/18/2007] [Indexed: 01/16/2023]
Abstract
Despite the immense global efforts, the malaria vaccine is not yet available and requires the identification of newer target molecules. Since tryptophan-rich proteins of P. yoelii have been proposed as vaccine candidates, we describe here the expression, purification and immunological characterization of a 55kDa Plasmodium vivax tryptophan- and alanine-rich antigen (PvTARAg55). This protein consists of 480 aa residues with a calculated molecular mass of 55.0kDa. It shows 42% aa sequence identity (64% homology) with PyPAg1 of P. yoelii and shares positional conservation of tryptophan residues. Sequence analysis of PvTARAg55 from different P. vivax isolates revealed that typtophan-rich domain which contains most of the B-cell epitopes was highly conserved in the parasite population while the alanine-rich domain showed polymorphism. Exon-2 covering major part (420 aa) of the protein including both the domains was PCR amplified, cloned, expressed in Escherichia coli, and the recombinant protein purified to its homogeneity. Majority of P. vivax-infected individuals (82.5%, n=40) produced antibodies against this antigen. Proliferative responses to the recombinant PvTARAg55 were observed in 60% (n=20) of individuals who had recently been exposed to the P. vivax infection. Measurement of Th1- (IFN-gamma, TNF-alpha, and IL-12) and Th2-type (IL-4 and IL-10) cytokine production in response to this recombinant antigen revealed a mixed type T-cell response with a Th2 response being more pronounced. These results demonstrate that PvTARAg55 elicits high humoral and cellular immune responses thus establishes its immunogenecity in humans.
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Affiliation(s)
- Asim A Siddiqui
- Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
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19
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Scholz SM, Simon N, Lavazec C, Dude MA, Templeton TJ, Pradel G. PfCCp proteins of Plasmodium falciparum: gametocyte-specific expression and role in complement-mediated inhibition of exflagellation. Int J Parasitol 2007; 38:327-40. [PMID: 17950739 DOI: 10.1016/j.ijpara.2007.08.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 08/02/2007] [Accepted: 08/06/2007] [Indexed: 10/22/2022]
Abstract
The sexual phase of the malaria parasite Plasmodium falciparum is essential for transmission of the disease and is accompanied by the co-ordinated expression of sexual stage proteins. Six of these proteins belong to a highly conserved apicomplexan family of multi-domain adhesion proteins, termed PfCCps. PfCCp1, PfCCp2 and PfCCp3 are co-dependently expressed in the parasitophorous vacuole associated with the gametocyte plasma membrane. PfCCp2 and PfCCp3 also play an essential role for parasite development in the mosquito. We show that the six PfCCp proteins are expressed in stages II-V of gametocytogenesis as well as during early gamete formation. The proteins are expressed in association with the surface of both male and female gametocytes and macrogametes, but are not present in exflagellating microgametes. Further, the newly described protein PfCCp4 co-localizes with the transmission blocking candidate Pfs230, with which it forms a protein complex. In contrast to the phenotypes that are observed following targeted gene disruption of PfCCp2, PfCCp3 or Pfs230, the lack of PfCCp4 expression does not inhibit parasite development in the mosquito vector. This indicates a non-essential role for this protein during parasite transmission. Exflagellation assays revealed that antibodies directed against distinct domains of PfCCp1 through PfCCp4 and PfFNPA support a complement-mediated decrease in gametocyte emergence. We conclude that the six PfCCp proteins are specifically expressed during gametocytogenesis and gamete formation, and that select members may represent prospective candidates for transmission blocking vaccines.
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Affiliation(s)
- Sabrina Maria Scholz
- University of Würzburg, Research Center for Infectious Diseases, Röntgenring 11, 97070 Würzburg, Germany
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20
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Pradel G. Proteins of the malaria parasite sexual stages: expression, function and potential for transmission blocking strategies. Parasitology 2007; 134:1911-29. [PMID: 17714601 DOI: 10.1017/s0031182007003381] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
SUMMARYThe sexual phase of the malaria pathogen,Plasmodium falciparum, culminates in fertilization within the midgut of the mosquito and represents a crucial step in the completion of the parasite's life-cycle and transmission of the disease. Two decades ago, the first sexual stage-specific surface proteins were identified, among themPfs230,Pfs48/45, andPfs25, which were of scientific interest as candidates for the development of transmission blocking vaccines. A decade later, gene information gained from the sequencing of theP. falciparumgenome led to the identification of numerous additional sexual-stage proteins with antigenic properties and novel enzymes that putatively possess regulatory functions during sexual-stage development. This review aims to summarize the sexual-stage proteins identified to date, to compare their stage specificities and expression patterns and to highlight novel regulative mechanisms of sexual differentiation. The prospective candidacy of select sexual-stage proteins as targets for transmission blocking strategies will be discussed.
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Affiliation(s)
- G Pradel
- University of Würzburg, Research Center for Infectious Diseases, Röntgenring 11, 97070 Würzburg, Germany.
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21
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Lanfrancotti A, Bertuccini L, Silvestrini F, Alano P. Plasmodium falciparum: mRNA co-expression and protein co-localisation of two gene products upregulated in early gametocytes. Exp Parasitol 2007; 116:497-503. [PMID: 17367781 DOI: 10.1016/j.exppara.2007.01.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Revised: 01/19/2007] [Accepted: 01/24/2007] [Indexed: 11/30/2022]
Abstract
Genes encoding Plasmodium falciparum proteins Pfs16 and Pfpeg3/mdv1, specifically appearing in the parasitophorous vacuole of the early gametocytes, are upregulated at the onset of sexual differentiation. Analysis of asexual development in gametocyte producing and non-producing clones of P. falciparum indicated that these genes are also transcribed at a low level in asexual parasites, although their protein products are not detectable in these stages by immunofluorescence. Immunoelectron microscopic analysis of stage II gametocytes indicated that Pfs16 and Pfpeg3/mdv1 proteins co-localise in the parasitophorous vacuole membrane and in all derived membranous structures (such as the multi-laminate membrane whorls of the circular clefts in the infected erythrocyte cytoplasm and the membranes of the gametocyte food vacuoles). In this analysis both proteins were also observed for the first time in the membrane and in the lumen of distinct cleft-like structures in the erythrocyte cytoplasm.
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Affiliation(s)
- Alessandra Lanfrancotti
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Rome, Italy
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22
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Giha HA, Elbashir MI, A-Elbasit IE, A-Elgadir TME, ElGhazali GE, Mackinnon MJ, Babiker HA. Drug resistance-virulence relationship in Plasmodium falciparum causing severe malaria in an area of seasonal and unstable transmission. Acta Trop 2006; 97:181-7. [PMID: 16336938 DOI: 10.1016/j.actatropica.2005.10.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 10/22/2005] [Accepted: 10/24/2005] [Indexed: 11/30/2022]
Abstract
The pathogenesis of severe Plasmodium falciparum malaria is still obscure, but is believed to be multi-factorial, and among the important factors are intrinsic parasite-properties. Here we investigated the association between clinical manifestation of P. falciparum malaria (an indicator of virulence) and two parasite properties--drug resistance and gametocyte production. Among 996 P. falciparum infections detected in the out-patient clinic of Gedarif Hospital in eastern Sudan, there was no significant association between the incidence of severe versus mild disease and the presence of resistant alleles at the chloroquine-resistance transporter locus (pfcrt-T76) and the multi-drug-resistance locus (pfmdr1-Y86). However, among severe cases, there was a significantly lower prevalence of parasites carrying resistant alleles among patients that died versus survived. There was a trend towards a higher gametocyte rate among severe malaria patients compared with uncomplicated malaria cases. These results are discussed in relation to the fitness of drug resistant parasites.
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Affiliation(s)
- Hayder A Giha
- Malaria Research Centre (MalRC), Department of Biochemistry, Faculty of Medicine, University of Khartoum, P.O. Box 102, Khartoum, Sudan.
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23
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Eksi S, Haile Y, Furuya T, Ma L, Su X, Williamson KC. Identification of a subtelomeric gene family expressed during the asexual-sexual stage transition in Plasmodium falciparum. Mol Biochem Parasitol 2005; 143:90-9. [PMID: 15996767 DOI: 10.1016/j.molbiopara.2005.05.010] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2005] [Revised: 05/05/2005] [Accepted: 05/25/2005] [Indexed: 11/24/2022]
Abstract
For malaria transmission, the parasite must undergo sexual differentiation into mature gametocytes. However, the molecular basis for this critical transition in the parasites life cycle is unknown. Six previously uncharacterized genes, Pfg14.744, Pfg14.745, Pfg14.748, Pfg14.763, Pfg14.752 and Pfg6.6 that are members of a 36 gene Plasmodium falciparum-specific subtelomeric superfamily were found to be expressed in parasites that are committed to sexual development as suggested by co-expression of Pfs16 and Pfg27. Northern blots demonstrated that Pfg14.744 and Pfg14.748 were first expressed before the parasites differentiated into morphologically distinct gametocytes, transcription continued to increase until stage II gametocytes were formed and then rapidly decreased. Immunofluorescence assays indicated that both proteins were only produced in the subpopulation of ring stage parasites that are committed to gametocytogenesis and both localized to the parasitophorous vacuole (PV)b of the early ring stage parasites. As the parasites continued to develop Pfg14.748 remained within the parasitophorous vacuole, while Pfg14.744 was detected in the erythrocyte. The 5' flanking region of either gene alone was sufficient to drive early gametocyte specific expression of green fluorescent protein (GFP). In parasites transfected with a plasmid containing the Pfg14.748 5' flanking region immediately upstream of GFP, fluorescence was observed in a small number of schizonts the cycle before stage I gametocytes were observed. This expression pattern is consistent with commitment to sexual differentiation prior to merozoite release and erythrocyte invasion. Further investigation into the role of these genes in the transition from asexual to sexual differentiation could provide new strategies to block malaria transmission.
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Affiliation(s)
- Saliha Eksi
- Loyola University Chicago, Department of Biology, 6525 North Sheridan Road, Chicago, IL 60626, USA
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24
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Silvestrini F, Bozdech Z, Lanfrancotti A, Di Giulio E, Bultrini E, Picci L, Derisi JL, Pizzi E, Alano P. Genome-wide identification of genes upregulated at the onset of gametocytogenesis in Plasmodium falciparum. Mol Biochem Parasitol 2005; 143:100-10. [PMID: 16026866 DOI: 10.1016/j.molbiopara.2005.04.015] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Revised: 04/19/2005] [Accepted: 04/21/2005] [Indexed: 11/23/2022]
Abstract
A genome-wide expression analysis was undertaken to identify novel genes specifically activated from early stages of gametocytogenesis in Plasmodium falciparum. A comparative analysis was conducted on sexually induced cultures of reference parasite clone 3D7 and its gametocyteless derivative clone F12. Competitive hybridisations on long-oligomer microarrays representing 4488 P. falciparum genes identified a remarkably small number of transcripts differentially produced in the two clones. Upregulation of the mRNAs for the early gametocyte markers Pfs16 and Pfg27 was however readily detected in 3D7, and such genes were used as reference transcripts in a comparative time course analysis of 3D7 and F12 parasites between 30 and 40 h post-invasion in cultures induced to enter gametocytogenesis. One hundred and seventeen genes had expression profiles which correlated to those of pfs16 and pfg27, and Northern blot analysis and published proteomic data identified those whose expression was gametocyte-specific. Immunofluorescence analysis with antibodies against two of these gene products identified two novel parasite membrane associated, sexual stage-specific proteins. One was produced from stage I gametocytes and the second showed peak production in stage II gametocytes. The two proteins were named Pfpeg-3 and Pfpeg-4, for P. falciparum proteins of early gametocytes.
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Affiliation(s)
- Francesco Silvestrini
- Dipartimento di Malattie Infettive Parassitarie e Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
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25
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Abstract
The sexual stages of the malaria parasite are highly specialized cells adapted to withstand major environmental changes during their development. They also induce immune responses that may affect the outcome of the infection in the mosquito. In this review Pietro Alano considers the nature and the role of the antigens expressed by Plasmodium sexual stages.
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Affiliation(s)
- P Alano
- Laboratorio di Biologia Cellulare, Istituto Superiore di Sanita, viale Regina Elena 299, 00161 Rome, Italy
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26
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Moreira CK, Marrelli MT, Jacobs-Lorena M. Gene expression in Plasmodium: from gametocytes to sporozoites. Int J Parasitol 2004; 34:1431-40. [PMID: 15582520 DOI: 10.1016/j.ijpara.2004.10.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Revised: 09/17/2004] [Accepted: 10/05/2004] [Indexed: 02/06/2023]
Abstract
Completion of the complex developmental program of Plasmodium in the mosquito is essential for parasite transmission, yet this part of its life cycle is still poorly understood. In recent years, considerable progress has been made in the identification and characterization of genes expressed during parasite development in the mosquito. This line of investigation was greatly facilitated by the availability of the genome sequence of several Plasmodium, and by the application of approaches such as proteomics, microarrays, gene disruption by homologous recombination (gene knockout) and by use of subtraction libraries. Here, we review what is presently known about genes expressed in gametocytes and during the Plasmodium life cycle in the mosquito.
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Affiliation(s)
- C K Moreira
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Malaria Research Institute, The Johns Hopkins University, 615 N Wolfe St., Baltimore, MD 21205, USA
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Kongkasuriyachai D, Fujioka H, Kumar N. Functional analysis of Plasmodium falciparum parasitophorous vacuole membrane protein (Pfs16) during gametocytogenesis and gametogenesis by targeted gene disruption. Mol Biochem Parasitol 2004; 133:275-85. [PMID: 14698439 DOI: 10.1016/j.molbiopara.2003.10.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Gametocytogenesis is a tightly regulated process marked by differentiation through distinct morphological forms and coordinated expression of sexual stage gene products. The earliest known gene product expressed at the onset of Plasmodium falciparum gametocytogenesis is Pfs16 localized on the parasitophorous vacuole membrane (PVM). Targeted gene disruption was undertaken to disrupt expression of Pfs16 and examine its potential role during sexual development. Three independent clones were demonstrated to have the coding sequence of Ps16 gene disrupted by the targeting plasmid by homologous recombination. No full-length transcripts and PVM localized 16 kDa protein were detected. Instead, all three "16ko" clones expressed a protein of 14 kDa recognized by Pfs16 specific antibodies that was mislocalized to an unidentified double membrane compartment in the parasites. Disruption of Pfs16 gene resulted in a significant reduction in gametocyte production, although the small number of gametocytes produced appeared to be normal by molecular and phenotypic evidences. Preliminary observation also suggested impaired ability of male gametocytes to exflagellate in vitro. Pfs16 does not appear to be essential for sexual development, instead may be required for optimal production of sexual parasites. Understanding mechanisms involved in the development of sexual stages of P. falciparum may identify novel targets for drugs and vaccines effective in reducing malaria transmission.
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Affiliation(s)
- Darin Kongkasuriyachai
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins Malaria Research Institute, Baltimore, MD 21205, USA
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Sharma A, Sharma I, Kogkasuriyachai D, Kumar N. Structure of a gametocyte protein essential for sexual development in Plasmodium falciparum. Nat Struct Mol Biol 2003; 10:197-203. [PMID: 12577051 DOI: 10.1038/nsb899] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2002] [Accepted: 01/02/2003] [Indexed: 11/08/2022]
Abstract
Malaria transmission is dependent on the development of sexual forms of Plasmodium falciparum, called gametocytes, in the vertebrate host. Pfg27 is an abundantly expressed sexual stage-specific protein that is essential for gametocytogenesis in P. falciparum. We describe the crystal structure of Pfg27, which reveals a novel fold composed of two pseudo dyad-related repeats of the helix-turn-helix motif. Structurally equivalent helices of each repeat either form a dimer interface or interact with RNA in vitro. One side of the dimer presents an unprecedented juxtaposition of four polyproline (PXXP) motifs. Preliminary binding data indicate that these sites are capable of binding Src homology-3 (SH3) modules. Molecular modeling suggests that the dimer can accommodate two SH3 modules simultaneously, potentially enabling molecular crosstalk between SH3-containing proteins. The structural and initial biochemical evidence suggests that Pfg27 may serve as a platform for RNA and SH3 binding.
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Affiliation(s)
- Amit Sharma
- Malaria group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
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29
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Kongkasuriyachai D, Kumar N. Functional characterisation of sexual stage specific proteins in Plasmodium falciparum. Int J Parasitol 2002; 32:1559-66. [PMID: 12435440 DOI: 10.1016/s0020-7519(02)00184-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The various stages of the malaria parasites in the vertebrate host and in the mosquito vector offer numerous candidates for vaccine and drug development. However, the biological complexity of the parasites and the interaction with the immune system of the host continue to frustrate all such efforts thus far. While most of the targets for drug and vaccine design have focused on the asexual stages, the sexual stages of the parasite are critical for transmission and maintenance of parasites among susceptible vertebrate hosts. Sexual stage parasites undergo a series of morphological and biochemical changes during their development, accompanied by a co-ordinated cascade of a distinct expression pattern of sexual stage specific proteins. Mechanisms underlying the developmental switch from asexual parasite to sexual parasite still remain elusive. Methods that can break the malaria transmission cycle thus occupy a central place in the overall malaria control strategies. This paper provides a review of genes expressed in sexually differentiated Plasmodium. In the past few years, a molecular approach based on targeted gene disruption has revealed fascinating biological roles for many of the sexual stage gene products. In addition, we will briefly discuss other functional genomic approaches employed to study not only sexual but also other aspects of host-parasite biology.
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Affiliation(s)
- Darin Kongkasuriyachai
- Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
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30
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Delrieu I, Waller CC, Mota MM, Grainger M, Langhorne J, Holder AA. PSLAP, a protein with multiple adhesive motifs, is expressed in Plasmodium falciparum gametocytes. Mol Biochem Parasitol 2002; 121:11-20. [PMID: 11985859 DOI: 10.1016/s0166-6851(02)00016-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A gene coding for a protein containing two Scavenger Receptor Cysteine-Rich (SRCR) motifs, four Limulus factor C, Coch-5b2 and Lgl1 (LCCL) motifs; and one Polycystin-1, Lipoxygenase and Alpha Toxin (PLAT) motif was cloned from Plasmodium chabaudi and homologues identified in the P. falciparum and P. yoelii genome data bases. At least one of these sequence motifs (SRCR) has adhesive properties in other proteins, therefore, we propose to name this protein PSLAP for Plasmodium SRCR, LCCL Adhesive-like Protein. Southern blotting and chromosome analysis showed that pslap is a single copy gene on chromosome 14 in P. falciparum 3D7. pslap mRNA is strongly expressed in P. falciparum gametocytes, but was undetectable on Northern blots of RNA from the asexual blood stages. Polyclonal antibodies raised to different parts of PSLAP detected a protein expressed in late gametocytes, but not in the early stages of gametocytogenesis or asexual blood stages of P. falciparum. We suggest that PSLAP functions in the mosquito, for example, in modulation of the invertebrate host immune response or in protection against complement factors in the blood meal.
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Affiliation(s)
- Isabelle Delrieu
- Division of Parasitology, National Institute for Medical Research, The Ridgeway, London, UK
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31
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Sallicandro P, Paglia MG, Hashim SO, Silvestrini F, Picci L, Gentile M, Mulaa F, Alano P. Repetitive sequences upstream of the pfg27/25 gene determine polymorphism in laboratory and natural lines of Plasmodium falciparum. Mol Biochem Parasitol 2000; 110:247-57. [PMID: 11071280 DOI: 10.1016/s0166-6851(00)00274-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The structure of the genomic region located upstream of the gametocyte-specific gene pfg27/25 of Plasmodium falciparum was analysed in laboratory lines and field isolates of the parasite. The gene is located in a subtelomeric region of chromosome 13 in parasite clones 3D7 and HB3. Analysis of laboratory lines and field isolates of P. falciparum indicated that polymorphism upstream of pfg27/25 is mainly due to the structure of a repetitive DNA region located at about half a kilobase from the pfg27/25 coding sequence. Different types of repetitive sequences are present in this region, whose copy number is variable in different parasite lines. In addition a GC-rich sequence element contained in this region, which is proposed to be the startpoint of pfg27/25 mRNA, presents either a direct or a reverse orientation in different parasite lines. Genomic deletions upstream of the pfg27/25 gene are also described in two laboratory lines of the parasite, which eliminate two newly identified malaria genes. orf P and orf Gap, from the genome of these parasites. One of them, orf Gap, deleted from the reference parasite clone 3D7, is abundantly expressed as mature mRNA in asexual parasites. PCR analysis on 64 field isolates of P. falciparum indicated that orf P and orf Gap sequences are present in all tested samples of naturally propagating parasites.
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Affiliation(s)
- P Sallicandro
- Laboratorio di Biologia Cellulare, Instituto Superiore di Sanità, Rome, Italy
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32
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Jenkins MC, Trout J, Murphy C, Harp JA, Higgins J, Wergin W, Fayer R. Cloning and expression of a DNA sequence encoding a 41-kilodalton Cryptosporidium parvum oocyst wall protein. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1999; 6:912-20. [PMID: 10548585 PMCID: PMC95797 DOI: 10.1128/cdli.6.6.912-920.1999] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study was conducted to produce a recombinant species-specific oocyst wall protein of Cryptosporidium parvum. Antigens unique to C. parvum were identified by gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting of oocyst proteins from several different Cryptosporidium species. Antiserum was then prepared against a 41-kDa antigen unique to C. parvum and used to identify a recombinant DNA clone, designated rCP41. Expression of CP41 mRNA in C. parvum oocysts was confirmed by reverse transcriptase PCR (RT-PCR). Although the CP41 sequence was shown by PCR to be present in the genome of C. baileyi, CP41 mRNA was not detected in this species by RT-PCR. Immunofluorescence staining with antiserum against recombinant CP41 detected native CP41 antigen on the surface of C. parvum oocysts but failed to detect CP41 on C. baileyi oocysts. Immunoelectron microscopy demonstrated that native CP41 was distributed unevenly on the C. parvum oocyst surface and was associated with amorphous oocyst wall material. In an enzyme-linked immunosorbent assay, purified rCP41 performed as well as native C. parvum oocyst protein in measuring the serological responses of young calves and adult cows to experimental and natural C. parvum infections. These results indicate that recombinant CP41 antigen may have potential in the immunodiagnosis of cryptosporidiosis.
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Affiliation(s)
- M C Jenkins
- Immunology and Disease Resistance Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, USA.
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33
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Dorin D, Alano P, Boccaccio I, Cicéron L, Doerig C, Sulpice R, Parzy D, Doerig C. An atypical mitogen-activated protein kinase (MAPK) homologue expressed in gametocytes of the human malaria parasite Plasmodium falciparum. Identification of a MAPK signature. J Biol Chem 1999; 274:29912-20. [PMID: 10514473 DOI: 10.1074/jbc.274.42.29912] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cDNA encoding Pfmap-2, an enzyme of the human malaria parasite Plasmodium falciparum, was cloned, sequenced, and expressed in Escherichia coli. The open reading frame carried by the Pfmap-2 cDNA encodes a 508-amino acid polypeptide of 59.2 kDa with maximal homology to mitogen-activated protein kinases (MAPKs) from various organisms. The purified recombinant enzyme displayed functional characteristics of MAPKs such as (i) ability to undergo autophosphorylation, (ii) ability to phosphorylate myelin basic protein, a classical MAPK substrate, (iii) regulation of kinase activity by a MAPK-specific phosphatase, and (iv) ability to be activated by component(s) present in cell extracts. Mutational analysis of the recombinant protein allowed the identification of residues that are important for enzymatic activity. Northern blot analysis and immunofluorescence assays indicated that Pfmap-2 is expressed specifically in gametocytes, the form that is responsible for transmission of the parasite to the mosquito vector. Gametocyte extracts activated recombinant Pfmap-2 more efficiently than extracts from asexual parasites, which is consistent with this stage specificity. Despite its overall high level of homology to MAPKs, Pfmap-2 presents the peculiarity of not possessing the conserved threonine-X-tyrosine activation motif usually found in enzymes of this family; instead, it has a threonine-serine-histidine at the same location. This atypical feature formed the basis for a detailed analysis of the primary structure of MAPKs, allowing us to define an operational MAPK signature, which is shared by Pfmap-2. The fact that no MAPK from vertebrates diverge in the activation motif suggests that the fine mechanisms of Pfmap-2 regulation may offer an opportunity for antimalarial drug targeting.
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Affiliation(s)
- D Dorin
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité 511, 91 Bd. de l'Hôpital, 75013 Paris, France
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34
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Lobo CA, Fujioka H, Aikawa M, Kumar N. Disruption of the Pfg27 locus by homologous recombination leads to loss of the sexual phenotype in P. falciparum. Mol Cell 1999; 3:793-8. [PMID: 10394367 DOI: 10.1016/s1097-2765(01)80011-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Transmission of malaria depends upon the differentiation and development of the sexual stages of the parasite. In Plasmodium falciparum, it is a complex, multistage process, involving the expression of a large number of sexual stage-specific proteins. Pfg27 is one such protein, abundantly expressed at the onset of gametocytogenesis. We report successful disruption of the Pfg27 locus using homologous recombination and show that it is essential for the maintenance of the sexual phenotype. Transfectants lacking Pfg27 abort early in sexual development, resulting in vacuolated, highly disarranged, and disintegrating parasites. This suggests a critical role for Pfg27 in the sexual development of the parasite.
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Affiliation(s)
- C A Lobo
- Department of Molecular Microbiology and Immunology, School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA
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35
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Contreras CE, Ploton IN, Siliciano RF, Karp CL, Viscidi R, Kumar N. Mapping of specific and promiscuous HLA-DR-restricted T-cell epitopes on the Plasmodium falciparum 27-kilodalton sexual stage-specific antigen. Infect Immun 1998; 66:3579-90. [PMID: 9673236 PMCID: PMC108389 DOI: 10.1128/iai.66.8.3579-3590.1998] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
We have characterized HLA-DR-restricted T-cell epitopes on the 27-kDa protein (Pfg27), a sexual stage-specific antigen, of the human malaria parasite Plasmodium falciparum in subjects with a history of malaria. Pfg27, expressed early in the sexual stages, is recognized by monoclonal antibodies capable of reducing the infectivity of gametocytes in mosquitoes. By using 16 Pfg27-specific CD4(+)-T-cell clones derived from three donors, seven different T-cell epitopes were identified. Among them, P11 (amino acids 191 to 210 of the Pfg27 sequence, IDVVDSYIIKPIPALPVTPD) was found to contain a previously described binding motif for multiple HLA-DR allotypes. Indeed, P11 was found to be promiscuous in that it could be recognized by T cells in the context of at least five different HLA-DR molecules. The cytokine profile of the clones was mixed. Seven of nine T-cell clones exhibited a Th0-like cytokine profile, producing high levels of gamma interferon (IFN-gamma) and interleukin-4 (IL-4) upon stimulation with specific peptides and mitogens. The other two clones had a Th1-like cytokine profile with high expression of IFN-gamma and no IL-4. Identification of a promiscuous epitope in Pfg27 could play a significant role in the design of a subunit vaccine for suppressing malaria transmission.
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Affiliation(s)
- C E Contreras
- Department of Molecular Microbiology and Immunology, School of Hygiene and Public Health, School of Medicine, The Johns Hopkins University, Baltimore, Maryland 21205, USA
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36
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Alano P, Silvestrini F, Roca L. Structure and polymorphism of the upstream region of the pfg27/25 gene, transcriptionally regulated in gametocytogenesis of Plasmodium falciparum. Mol Biochem Parasitol 1996; 79:207-17. [PMID: 8855557 DOI: 10.1016/0166-6851(96)02663-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Transcription of the early gametocyte-specific gene pfg27/25, and genomic structure and polymorphism of its upstream region were studied in the human malaria parasite Plasmodium falciparum. The upstream genomic sequence of the pfg27/25 gene is characterised by a repetitive region that contains five direct and one inverted repeats of a unit constituted by a perfectly conserved sequence flanked by a poly-dT and a poly-d(AT) tract. Sequences further upstream from the repetitive region are polymorphic in distantly related parasite lines. Nuclear 'run off' experiments indicated that transcription of pfg27/25 is developmentally regulated. Transcription of the gene, undetectable in asexual parasites, is activated at the onset of gametocytogenesis. Te gene is transcribed in a 2.5 kb mature mRNA for the first 2-3 days of sexual differentiation, while transcription is down-regulated in more mature gametocytes.
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Affiliation(s)
- P Alano
- Laboratorio di Biologia Cellulare, Istituto Superiore di Sanità, Rome, Italy
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37
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Ploton IN, Wizel B, Viscidi R, Kumar N. Mapping of two overlapping linear epitopes in Pfg27 recognized by Plasmodium falciparum transmission-blocking monoclonal antibodies. Vaccine 1995; 13:1161-9. [PMID: 8578799 DOI: 10.1016/0264-410x(95)00033-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have reported previously the production of Plasmodium falciparum transmission-blocking monoclonal antibodies (mAb) recognizing a reduction-insensitive cross-reacting epitope in the gametocyte antigen Pfg27 and the gamete surface antigens Pfs230 and Pfs48/45. In this study, the amino acid sequence of this epitope in Pfg27 was determined. First, the epitope was localized near the N terminus of the protein by probing recombinant overlapping fragments spanning Pfg27 with transmission-blocking mAb in immunoblot experiments. The amino acid sequence of the epitope was then determined by using overlapping synthetic peptides spanning the smallest immunoreactive recombinant fragment in an ELISA. The sequence KPLDKFGNIYDYHYEH (amino acids 10-25 in the Pfg27 sequence) was shown to contain two overlapping epitopes recognized by transmission-blocking mAb. Comparison of the sequence of the gene encoding Pfg27 in seven different P. falciparum strains demonstrated that these sequential epitopes are totally conserved. Immunization of mice with synthetic peptides derived from Pfg27, conjugated with keyhole limpet hemocyanin (KLH) and formulated in Freund's adjuvant or alum, resulted in the production of antibodies capable of recognizing the peptides as well as the native Pfg27.
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Affiliation(s)
- I N Ploton
- Department of Molecular Microbiology and Immunology, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
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38
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Doerig C, Doerig C, Horrocks P, Coyle J, Carlton J, Sultan A, Arnot D, Carter R. Pfcrk-1, a developmentally regulated cdc2-related protein kinase of Plasmodium falciparum. Mol Biochem Parasitol 1995; 70:167-74. [PMID: 7637697 DOI: 10.1016/0166-6851(95)00033-w] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A gene encoding a novel cdc2-related protein kinase has been identified in Plasmodium falciparum, using degenerate oligonucleotides designed to hybridise to regions that are conserved in members of the cdc2 gene family. This gene, called Pfcrk-1, is located on chromosome 4. It is most closely related to the p58GTA gene family, members of which are negative regulators of cell growth in vertebrates. Pfcrk-1 is developmentally regulated, as indicated by stage-specific accumulation of mRNA in gametocytes.
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Affiliation(s)
- C Doerig
- Institute of Cell, Animal and Population Biology, University of Edinburgh, UK
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39
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Pologe LG. Aberrant transcription and the failure of Plasmodium falciparum to differentiate into gametocytes. Mol Biochem Parasitol 1994; 68:35-43. [PMID: 7891746 DOI: 10.1016/0166-6851(94)00142-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In the human malaria parasite, Plasmodium falciparum, a DNA rearrangement is associated with erroneous transcription of the early gametocyte antigen gene, Pfg27/25, and the failure of the blood stages to differentiate into gametocytes. Altered blood stage-specific patterns of mRNA accumulation were observed for the Pfg27/25 gene, in mutant P. falciparum parasites that have lost the capacity to differentiate sexually. Each mutant demonstrates a DNA rearrangement upstream of the coding sequence. The location of the gene proximal breakpoint correlates with the complete absence of stable Pfg27/25 transcripts or with the accumulation of aberrant Pfg27/25 mRNAs in the asexual stages. The rearrangement identifies a labile region of the genome which contributes to accurate stage-specific Pfg27/25 gene transcription and may be necessary for a critical early step in sexual differentiation.
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Affiliation(s)
- L G Pologe
- Department of Medical and Molecular Parasitology, New York University Medical Center, NY 10010
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40
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Read D, Lensen AH, Begarnie S, Haley S, Raza A, Carter R. Transmission-blocking antibodies against multiple, non-variant target epitopes of the Plasmodium falciparum gamete surface antigen Pfs230 are all complement-fixing. Parasite Immunol 1994; 16:511-9. [PMID: 7532850 DOI: 10.1111/j.1365-3024.1994.tb00305.x] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We have studied the properties of 16 newly derived monoclonal antibodies (MoAbs) against Pfs230, a gamete surface protein of Plasmodium falciparum and a target of transmission-blocking antibodies. All 16 MoAbs recognized Pfs230 by immunoprecipitation from non-ionic detergent extracts of the protein radio-labelled with 125Iodine. The MoAbs also recognized this protein on Western blots under non-reducing conditions but none of them recognized the protein under reducing conditions. Using an immunoradiometric assay the MoAbs appear to define nine different epitope regions. The MoAbs were tested for their ability to lyse extra-cellular female gametes of P. falciparum isolate 3D7. Eight of the MoAbs, all of isotype IgG2a, mediated complement-dependent lysis of the gametes; seven of the MoAbs, all isotype IgG1, failed to lyse the gametes in the presence of active complement. The eight complement-fixing MoAbs mediated almost total suppression of infectivity of gametocytes of P. falciparum 3D7 to mosquitoes; where tested this suppression was mainly complement-dependent. The seven non-complement-fixing MoAbs had no significant effect on the infectivity of gametocytes of P. falciparum 3D7 to mosquitoes. When tested by immunofluorescence the target epitopes of all the MoAbs were conserved in each of the five different isolates of P. falciparum which were tested.
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Affiliation(s)
- D Read
- Institute of Cell Animal and Population Biology, University of Edinburgh, UK
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41
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Plasmodium falciparum S-adenosylhomocysteine hydrolase. cDNA identification, predicted protein sequence, and expression in Escherichia coli. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)34016-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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42
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Sultan AA, Richardson WA, Alano P, Arnot DE, Doerig C. Cloning and characterisation of a Plasmodium falciparum homologue of the Ran/TC4 signal transducing GTPase involved in cell cycle control. Mol Biochem Parasitol 1994; 65:331-8. [PMID: 7969273 DOI: 10.1016/0166-6851(94)90083-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
On the basis of conserved sequences characteristic of the Ran/TC4 subfamily of the GTPase superfamily, a fragment of the gene encoding a Plasmodium falciparum Ran/TC4 homologue was amplified in the polymerase chain reaction. The fragment was used to screen a cDNA library to obtain clones which allowed determination of the complete gene sequence. The gene, designated pfran (Plasmodium falciparum ras-like nuclear protein), has around 70% amino acid identity with previously characterised Ran/TC4 proteins. Like other malarial mRNAs, the pfran mRNA contains a long (at least 679 bp) 5' untranslated region. Southern blotting experiments show that pfran is a single copy gene located on chromosome 11. RNA hybridisation experiments indicate that pfran mRNA is abundant in late trophozoite and schizont stages, but present at very low levels in gametocytes and early asexual stages.
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Affiliation(s)
- A A Sultan
- Institute of Cell, Animal and Population Biology, University of Edinburgh, Ashworth Laboratories, Scotland, UK
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43
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Bruce MC, Carter RN, Nakamura K, Aikawa M, Carter R. Cellular location and temporal expression of the Plasmodium falciparum sexual stage antigen Pfs16. Mol Biochem Parasitol 1994; 65:11-22. [PMID: 7935618 DOI: 10.1016/0166-6851(94)90111-2] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The temporal expression during gametogenesis and the cellular location of the sexual stage specific protein Pfs16, a putative integral membrane protein of Plasmodium falciparum, was investigated using two monoclonal antibodies, 2G7 and 93A3A2. Using sorbitol synchronised, in vitro gametocyte cultures along with immunofluorescence assays, the time at which Pfs16 is first expressed during gametogenesis has been estimated to 35 hours post merozoite invasion. By immunofluorescence assays on thin blood smears monoclonal antibodies specific for Pfs16 react strongly with the gametocyte and also with vesicles within the red blood cell cytoplasm, many of which connect with the gametocyte cell. Purification of parasitophorous vacuole membranes from mature and immature gametocytes and immunoelectron microscopy on gametocytes during gametogenesis have allowed us to locate Pfs16 to the parasitophorous vacuole membrane. During gametogenesis this membrane is shed along with the red blood cell membrane. Immunofluorescence assays and immunoelectron microscopy studies of emerged gametes indicate that in a minority of cases the parasitophorous vacuole membrane along with Pfs16 can be retained to some extent on the gamete surface.
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Affiliation(s)
- M C Bruce
- Institute of Cell, Animal and Population Biology, University of Edinburgh, UK
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44
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Kocken CH, Jansen J, Kaan AM, Beckers PJ, Ponnudurai T, Kaslow DC, Konings RN, Schoenmakers JG. Cloning and expression of the gene coding for the transmission blocking target antigen Pfs48/45 of Plasmodium falciparum. Mol Biochem Parasitol 1993; 61:59-68. [PMID: 8259133 DOI: 10.1016/0166-6851(93)90158-t] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The gene encoding the gametocyte/gamete-specific membrane protein Pfs48/45 of Plasmodium falciparum has been cloned. The Pfs48/45 gene is a non-interrupted, single copy gene that codes for a hydrophobic, non-repetitive protein of 448 amino acid residues containing a putative signal peptide at the N-terminus, a hydrophobic C-terminus and 7 potential N-glycosylation sites. Antibodies directed against a Pfs48/45-glutathione-S-transferase fusion protein reacted with both the 45-kDa and 48-kDa proteins of gametocytes. When Pfs48/45 is expressed in the baculovirus-insect cell system the recombinant Pfs48/45 protein is targeted and exposed to the insect cell surface in such a configuration that it is recognized by transmission-blocking anti-45/48-kDa monoclonal antibodies.
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Affiliation(s)
- C H Kocken
- Department of Molecular Biology, Faculty of Science, Nijmegen, The Netherlands
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45
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Abstract
Antibodies to sexual stage malaria parasites block transmission of Plasmodium by female mosquitoes. With the recent isolation of genes encoding several of the target antigens of transmission-blocking antibodies, the development of a subunit transmission-blocking vaccine against malaria is now a realistic goal.
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Affiliation(s)
- D C Kaslow
- Laboratory of Malaria Research, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
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46
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Paton MG, Barker GC, Matsuoka H, Ramesar J, Janse CJ, Waters AP, Sinden RE. Structure and expression of a post-transcriptionally regulated malaria gene encoding a surface protein from the sexual stages of Plasmodium berghei. Mol Biochem Parasitol 1993; 59:263-75. [PMID: 8341324 DOI: 10.1016/0166-6851(93)90224-l] [Citation(s) in RCA: 141] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The sexual stage-specific protein Pbs21 of the rodent malaria parasite Plasmodium berghei, expressed on the surface of zygotes and ookinetes, has been shown to induce an effective and long-lasting transmission blocking immunity. The gene encoding Pbs21 was cloned by screening a cDNA library prepared from enriched zygotes and ookinetes using the monoclonal antibody 13.1.15, which is capable of blocking subsequent parasite sexual development in the mosquito vector. The Pbs21 gene encoded a protein of 213 amino acids which contained a putative amino-terminal signal sequence and a putative carboxy-terminal hydrophobic membrane anchor. The amino-acid sequence was characterised by a large number of cysteine residues which were organized into 4 epidermal growth factor-like domains. The spacing of the cysteine residues was highly conserved when compared to the 25-kDa ookinete proteins of Plasmodium falciparum (Pfs25), Plasmodium reichenowi (Prs25) and Plasmodium gallinaceum (Pgs25) which were approximately 45%, 45% and 40% homologous to Pbs21 respectively. The gene is located on chromosome 5 and cross-hybridizes to a similarly defined gene unit in the other rodent malaria species Plasmodium chabaudi, Plasmodium vinckei and Plasmodium yoelii. The gene is internally disposed and not in the subtelomeric region of chromosome 5. The gene is transcribed in a stage-specific manner giving rise to an abundant 1.5-kb transcript. This mRNA is synthesised in the precursor cells to female gametes (gametocytes) however the protein is observed only after activation of the gametes, suggesting that translation of the mRNA is controlled by a post-transcriptional process. The Pbs21 gene and the P. berghei parasite system provide an excellent vehicle for the study of stage-specific transcriptional and post-transcriptional control in malaria.
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Affiliation(s)
- M G Paton
- Department of Biology, Imperial College of Science, Technology and Medicine, London, UK
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47
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Lal AA, Goldman IF, Collins WE, Kumar N. Sequence of a 27-kilodalton gamete antigen of Plasmodium reichenowi and comparison with Pfg27 of Plasmodium falciparum. Mol Biochem Parasitol 1993; 59:175-6. [PMID: 8515780 DOI: 10.1016/0166-6851(93)90019-t] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- A A Lal
- Malaria Branch, Centers for Disease Control and Prevention, Atlanta, GA
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