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Lima C, Verdaguer IB, Wunderlich G, Katzin AM, Crabb BS, Gilson PR, Azevedo MF. Conditional expression of NanoLuc luciferase through a multimodular system offers rapid detection of antimalarial drug activity. Exp Parasitol 2023; 254:108620. [PMID: 37716462 DOI: 10.1016/j.exppara.2023.108620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/06/2023] [Accepted: 09/12/2023] [Indexed: 09/18/2023]
Abstract
Conditional gene expression is a powerful tool to investigate putative vaccine and drug targets, especially in a haploid organism such as Plasmodium falciparum. Inducible systems based on regulation of either transcription, translation, protein or mRNA stability, among others, allow switching on an off the expression of any desired gene causing specific gain or loss of function phenotypes. However, those systems can be cumbersome involving the construction of large plasmids and generation of multiple transgenic parasite lines. In addition, the dynamic range of regulation achieved is not predictable for each individual gene and can be insufficient to generate detectable phenotypes when the genes of interest are silenced. Here, we combined up to three distinct inducible systems to regulate the expression of a single gene. Expression of the reporter NanoLuc luciferase was regulated over 40-fold, which correlates to the regulation achieved by each individual system multiplied by each other. We applied the conditionally expressed NanoLuc to evaluate the effect of fast-acting antimalarials such as chloroquine and artesunate as well as of slower-acting ones such as atovaquone. The conditionally expressed reporter allowed faster and more reliable detection of toxicity to the parasite, which correlated to the expected action of each compound. Bioluminescence achieved by the expression of this inducible highly sensitive reporter is therefore a promising tool to investigate the temporal effect of potential new antimalarials. This single plasmid combination system might also prove useful to achieve sufficient regulation of genes of interest to produce loss-of-function phenotypes.
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Affiliation(s)
- Caroline Lima
- Federal University of Sao Paulo, Santos, Sao Paulo, Brazil
| | - Ignasi B Verdaguer
- Departamento de Parasitologia, Instituto de Ciência Biomédicas, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil
| | - Gerhard Wunderlich
- Departamento de Parasitologia, Instituto de Ciência Biomédicas, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil
| | - Alejandro M Katzin
- Departamento de Parasitologia, Instituto de Ciência Biomédicas, Universidade de São Paulo, Avenida Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-900, Brazil
| | - Brendan S Crabb
- Burnet Institute, Melbourne, VIC, 3004, Australia; University of Melbourne, VIC, 3052, Australia; Monash University, Melbourne, VIC, 3004, Australia
| | - Paul R Gilson
- Burnet Institute, Melbourne, VIC, 3004, Australia; University of Melbourne, VIC, 3052, Australia
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2
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Vallintine T, van Ooij C. Timing of dense granule biogenesis in asexual malaria parasites. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001389. [PMID: 37647112 PMCID: PMC10482371 DOI: 10.1099/mic.0.001389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/15/2023] [Indexed: 09/01/2023]
Abstract
Malaria is an important infectious disease that continues to claim hundreds of thousands of lives annually. The disease is caused by infection of host erythrocytes by apicomplexan parasites of the genus Plasmodium. The parasite contains three different apical organelles - micronemes, rhoptries and dense granules (DGs) - whose contents are secreted to mediate binding to and invasion of the host cell and the extensive remodelling of the host cell that occurs following invasion. Whereas the roles of micronemes and rhoptries in binding and invasion of the host erythrocyte have been studied in detail, the roles of DGs in Plasmodium parasites are poorly understood. They have been proposed to control host cell remodelling through regulated protein secretion after invasion, but many basic aspects of the biology of DGs remain unknown. Here we describe DG biogenesis timing for the first time, using RESA localization as a proxy for the timing of DG formation. We show that DG formation commences approximately 37 min prior to schizont egress, as measured by the recruitment of the DG marker RESA. Furthermore, using a bioinformatics approach, we aimed to predict additional cargo of the DGs and identified the J-dot protein HSP40 as a DG protein, further supporting the very early role of these organelles in the interaction of the parasite with the host cell.
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Affiliation(s)
- Tansy Vallintine
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Christiaan van Ooij
- Faculty of Infectious Diseases, London School of Hygiene & Tropical Medicine, London, UK
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3
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Elsworth B, Keroack C, Rezvani Y, Paul A, Barazorda K, Tennessen J, Sack S, Moreira C, Gubbels MJ, Meyers M, Zarringhalam K, Duraisingh M. Babesia divergens egress from host cells is orchestrated by essential and druggable kinases and proteases. RESEARCH SQUARE 2023:rs.3.rs-2553721. [PMID: 36909484 PMCID: PMC10002801 DOI: 10.21203/rs.3.rs-2553721/v1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
Apicomplexan egress from host cells is fundamental to the spread of infection and is poorly characterized in Babesia spp., parasites of veterinary importance and emerging zoonoses. Through the use of video microscopy, transcriptomics and chemical genetics, we have implicated signaling, proteases and gliding motility as key drivers of egress by Babesia divergens. We developed reverse genetics to perform a knockdown screen of putative mediators of egress, identifying kinases and proteases involved in distinct steps of egress (ASP3, PKG and CDPK4) and invasion (ASP2, ASP3 and PKG). Inhibition of egress leads to continued intracellular replication, indicating exit from the replication cycle is uncoupled from egress. Chemical genetics validated PKG, ASP2 and ASP3 as druggable targets in Babesia spp. All taken together, egress in B. divergens more closely resembles T. gondii than the more evolutionarily-related Plasmodium spp. We have established a molecular framework for biological and translational studies of B. divergens egress.
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4
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Prata IO, Cubillos EFG, Krüger A, Barbosa D, Martins J, Setubal JC, Wunderlich G. Plasmodium falciparum Acetyl-CoA Synthetase Is Essential for Parasite Intraerythrocytic Development and Chromatin Modification. ACS Infect Dis 2021; 7:3224-3240. [PMID: 34766750 DOI: 10.1021/acsinfecdis.1c00414] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The malaria parasite Plasmodium falciparum possesses a unique Acetyl-CoA Synthetase (PfACS), which provides acetyl moieties for different metabolic and regulatory cellular pathways. We characterized PfACS and studied its role focusing on epigenetic modifications using the var gene family as reporter genes. For this, mutant lines to modulate plasmodial ACS expression by degron-mediated protein degradation and ribozyme-induced transcript decay were created. Additionally, an inhibitor of the human Acetyl-CoA Synthetase 2 was tested for its effectiveness in interfering with PfACS. The knockdown of PfACS or its inhibition resulted in impaired parasite growth. Decreased levels of PfACS also led to differential histone acetylation patterns, altered variant gene expression, and concomitantly decreased cytoadherence of infected red blood cells containing knocked-down parasites. Further, ChIP analysis revealed the presence of PfACS in many loci in ring stage parasites, underscoring its involvement in the regulation of chromatin. Due to its central function in the plasmodial metabolism and significant differences to human ACS, PfACS is an interesting target for drug development.
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Affiliation(s)
- Isadora Oliveira Prata
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, 05508-000 São Paulo-SP, Brazil
| | - Eliana Fernanda Galindo Cubillos
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, 05508-000 São Paulo-SP, Brazil
| | - Arne Krüger
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, 05508-000 São Paulo-SP, Brazil
| | - Deibs Barbosa
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes 748, 05508-000 São Paulo-SP, Brazil
| | - Joaquim Martins
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes 748, 05508-000 São Paulo-SP, Brazil
| | - João Carlos Setubal
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, Avenida Professor Lineu Prestes 748, 05508-000 São Paulo-SP, Brazil
| | - Gerhard Wunderlich
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1374, 05508-000 São Paulo-SP, Brazil
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Cubillos EFG, Prata IO, Fotoran WL, Ranford-Cartwright L, Wunderlich G. The Transcription Factor PfAP2-O Influences Virulence Gene Transcription and Sexual Development in Plasmodium falciparum. Front Cell Infect Microbiol 2021; 11:669088. [PMID: 34268135 PMCID: PMC8275450 DOI: 10.3389/fcimb.2021.669088] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/23/2021] [Indexed: 12/02/2022] Open
Abstract
The human malaria parasite Plasmodium falciparum expresses variant PfEMP1 proteins on the infected erythrocyte, which function as ligands for endothelial receptors in capillary vessels, leading to erythrocyte sequestration and severe malaria. The factors that orchestrate the mono-allelic expression of the 45–90 PfEMP1-encoding var genes within each parasite genome are still not fully identified. Here, we show that the transcription factor PfAP2-O influences the transcription of var genes. The temporary knockdown of PfAP2-O leads to a complete loss of var transcriptional memory and a decrease in cytoadherence in CD36 adherent parasites. AP2-O-knocked-down parasites exhibited also significant reductions in transmission through Anopheles mosquitoes. We propose that PfAP2-O is, beside its role in transmission stages, also one of the virulence gene transcriptional regulators and may therefore be exploited as an important target to disrupt severe malaria and block parasite transmission.
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Affiliation(s)
- Eliana F G Cubillos
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Isadora Oliveira Prata
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Wesley Luzetti Fotoran
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Lisa Ranford-Cartwright
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
| | - Gerhard Wunderlich
- Department of Parasitology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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Abstract
Malaria, caused by infection with Plasmodium parasites, remains a significant global health concern. For decades, genetic intractability and limited tools hindered our ability to study essential proteins and pathways in Plasmodium falciparum, the parasite associated with the most severe malaria cases. However, recent years have seen major leaps forward in the ability to genetically manipulate P. falciparum parasites and conditionally control protein expression/function. The conditional knockdown systems used in P. falciparum target all 3 components of the central dogma, allowing researchers to conditionally control gene expression, translation, and protein function. Here, we review some of the common knockdown systems that have been adapted or developed for use in P. falciparum. Much of the work done using conditional knockdown approaches has been performed in asexual, blood-stage parasites, but we also highlight their uses in other parts of the life cycle and discuss new ways of applying these systems outside of the intraerythrocytic stages. With the use of these tools, the field’s understanding of parasite biology is ever increasing, and promising new pathways for antimalarial drug development are being discovered.
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Liu C, Yang Z, Cai M, Shi Y, Cui H, Yuan J. Generation of Plasmodium yoelii malaria parasite for conditional degradation of proteins. Mol Biochem Parasitol 2020; 241:111346. [PMID: 33307135 DOI: 10.1016/j.molbiopara.2020.111346] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 11/30/2020] [Accepted: 12/02/2020] [Indexed: 11/28/2022]
Abstract
The auxin-inducible degron (AID) system is a robust chemical-genetic method for manipulating endogenous protein level by conditional proteasomal degradation via a small molecule. So far, this system has not been adapted in the P. yoelii, an important and widely used Plasmodium rodent parasite model for malaria biology. Here, using the CRISPR/Cas9 genome editing method, we generated two marker-free transgenic P. yoelii parasite lines (eef1a-Tir1 and soap-Tir1) stably expressing the Oryza sativa gene tir1 under the promoters of eef1a and soap respectively. These two lines develop normally during the parasite life cycle. In these backgrounds, we used the CRISPR/Cas9 method to tag two genes (cdc50c and fbxo1) with the AID motif and interrogate the expression of these two proteins with auxin. The eef1a-Tir1 line allows efficient degradation of the AID-tagged endogenous protein in the asexual schizont and sexual gametocyte stages, while the soap-Tir1 line allows protein degradation in the ookinetes. These two lines will be a useful resource for studying the Plasmodium parasite biology based on the P. yoelii.
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Affiliation(s)
- Chuanyuan Liu
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Zhenke Yang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Mengya Cai
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Yang Shi
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Huiting Cui
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Jing Yuan
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Signal Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China.
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Abstract
Malaria elimination efforts have been repeatedly hindered by the evolution and spread of multidrug-resistant strains of Plasmodium falciparum. The absence of a commercially available vaccine emphasizes the need for a better understanding of Plasmodium biology in order to further translational research. This has been partly facilitated by targeted gene deletion strategies for the functional analysis of parasite genes. However, genes that are essential for parasite replication in erythrocytes are refractory to such methods, and require conditional knockdown or knockout approaches to dissect their function. One such approach is the TetR-DOZI system that employs multiple synthetic aptamers in the untranslated regions of target genes to control their expression in a tetracycline-dependent manner. Maintaining modified parasites with intact aptamer copies has been challenging since these repeats can be lost by recombination. By interspacing the aptamers with unique sequences, we created a stable genetic system that remains effective at controlling target gene expression. One of the most powerful approaches to understanding gene function involves turning genes on and off at will and measuring the impact at the cellular or organismal level. This particularly applies to the cohort of essential genes where traditional gene knockouts are inviable. In Plasmodium falciparum, conditional control of gene expression has been achieved by using multicomponent systems in which individual modules interact with each other to regulate DNA recombination, transcription, or posttranscriptional processes. The recently devised TetR-DOZI aptamer system relies on the ligand-regulatable interaction of a protein module with synthetic RNA aptamers to control the translation of a target gene. This technique has been successfully employed to study essential genes in P. falciparum and involves the insertion of several aptamer copies into the 3′ untranslated regions (UTRs), which provide control over mRNA fate. However, aptamer repeats are prone to recombination and one or more copies can be lost from the system, resulting in a loss of control over target gene expression. We rectified this issue by redesigning the aptamer array to minimize recombination while preserving the control elements. As proof of concept, we compared the original and modified arrays for their ability to knock down the levels of a putative essential apicoplast protein (PF3D7_0815700) and demonstrated that the modified array is highly stable and efficient. This redesign will enhance the utility of a tool that is quickly becoming a favored strategy for genetic studies in P. falciparum. IMPORTANCE Malaria elimination efforts have been repeatedly hindered by the evolution and spread of multidrug-resistant strains of Plasmodium falciparum. The absence of a commercially available vaccine emphasizes the need for a better understanding of Plasmodium biology in order to further translational research. This has been partly facilitated by targeted gene deletion strategies for the functional analysis of parasite genes. However, genes that are essential for parasite replication in erythrocytes are refractory to such methods, and require conditional knockdown or knockout approaches to dissect their function. One such approach is the TetR-DOZI system that employs multiple synthetic aptamers in the untranslated regions of target genes to control their expression in a tetracycline-dependent manner. Maintaining modified parasites with intact aptamer copies has been challenging since these repeats can be lost by recombination. By interspacing the aptamers with unique sequences, we created a stable genetic system that remains effective at controlling target gene expression.
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Understanding the potency of malarial ligand (D44) in plasmodium FKBP35 and modelled halogen atom (Br, Cl, F) functional groups. J Mol Graph Model 2020; 97:107553. [PMID: 32035313 DOI: 10.1016/j.jmgm.2020.107553] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 01/10/2020] [Accepted: 01/27/2020] [Indexed: 11/21/2022]
Abstract
The present study clearly depicts the understanding of the D44 in Plasmodium FKBP35 around the hinge region. To analyse the binding stability of D44 ligand and to understand the role of halogen bond, hydrogen bond interaction formed between the hinge region amino acids: Isoleucine (Ile74), Phenylalanine (Phe54), Aspartic acid (Asp55) Phenylalanine (Phe64),Tyrosine (Tyr100), Tryptophan (TRP 77) and ligand D44 was portrayed specifically through interaction energy calculations at HF, M062X, MP2 level of theories for different basis set (6-311G**, 6-31+G*, LANL2DZ). The investigation will provide an apparent picture regarding the non-covalent interaction that hold the contact of ligand and amino acids in the hinge region and the implication of modelled functional groups (Br, Cl, F, OSO and NH2) on ligand, which will help chemist in synthesizing new novel ligands. HOMO, LUMO chart calculated for D44 ligands reveals graphic illustration of orbital's that stimulate for contact. The aim and natural bond orbital analysis identified key contribution of individual hydrogen/halogen bonds that contribute for the binding strength through stabilization energy, ρ and ∇2ρ values. Overall this study finds out that the Stability of D44 in Plasmodium FKBP35 was enhanced by the Halogen atom (Br, Cl, F) functional groups; which provide an innovative pathway for the selection of functional groups that opt for the hinge region side chains on the ligand.
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Biosynthesis of heme O in intraerythrocytic stages of Plasmodium falciparum and potential inhibitors of this pathway. Sci Rep 2019; 9:19261. [PMID: 31848371 PMCID: PMC6917786 DOI: 10.1038/s41598-019-55506-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 11/29/2019] [Indexed: 12/26/2022] Open
Abstract
A number of antimalarial drugs interfere with the electron transport chain and heme-related reactions; however, the biosynthesis of heme derivatives in Plasmodium parasites has not been fully elucidated. Here, we characterized the steps that lead to the farnesylation of heme. After the identification of a gene encoding heme O synthase, we identified heme O synthesis in blood stage parasites through the incorporation of radioactive precursors. The presence of heme O synthesis in intraerythrocytic stages of Plasmodium falciparum was confirmed by mass spectrometry. Inabenfide and uniconazole-P appeared to interfere in heme synthesis, accordingly, parasite growth was also affected by the addition of these drugs. We conclude that heme O synthesis occurs in blood stage-P. falciparum and this pathway could be a potential target for antimalarial drugs.
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Artemisinin kills malaria parasites by damaging proteins and inhibiting the proteasome. Nat Commun 2018; 9:3801. [PMID: 30228310 PMCID: PMC6143634 DOI: 10.1038/s41467-018-06221-1] [Citation(s) in RCA: 165] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 08/24/2018] [Indexed: 01/16/2023] Open
Abstract
Artemisinin and its derivatives (collectively referred to as ARTs) rapidly reduce the parasite burden in Plasmodium falciparum infections, and antimalarial control is highly dependent on ART combination therapies (ACTs). Decreased sensitivity to ARTs is emerging, making it critically important to understand the mechanism of action of ARTs. Here we demonstrate that dihydroartemisinin (DHA), the clinically relevant ART, kills parasites via a two-pronged mechanism, causing protein damage, and compromising parasite proteasome function. The consequent accumulation of proteasome substrates, i.e., unfolded/damaged and polyubiquitinated proteins, activates the ER stress response and underpins DHA-mediated killing. Specific inhibitors of the proteasome cause a similar build-up of polyubiquitinated proteins, leading to parasite killing. Blocking protein synthesis with a translation inhibitor or inhibiting the ubiquitin-activating enzyme, E1, reduces the level of damaged, polyubiquitinated proteins, alleviates the stress response, and dramatically antagonizes DHA activity. Artemisinin (ART) is a widely used antimalarial drug, but its mechanism of action is poorly understood. Here, Bridgford et al. show that ART kills parasites by a two-pronged mechanism, causing protein damage and compromising proteasome function, and that accumulation of proteasome substrates activates the ER stress response.
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12
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Plasmodium falciparum histidine triad protein and calmodulin modulates calcium homeostasis and intracellular proteolysis. Biochem Biophys Res Commun 2018; 503:722-728. [DOI: 10.1016/j.bbrc.2018.06.067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 06/13/2018] [Indexed: 10/28/2022]
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Gabriel HB, Azevedo MF, Kimura EA, Katzin AM. Plasmodium falciparum parasites overexpressing farnesyl diphosphate synthase/geranylgeranyl diphosphate synthase are more resistant to risedronate. Mem Inst Oswaldo Cruz 2018; 113:e180174. [PMID: 30110072 PMCID: PMC6086031 DOI: 10.1590/0074-02760180174] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/25/2018] [Indexed: 01/21/2023] Open
Abstract
Farnesyl diphosphate synthase/geranylgeranyl diphosphate synthase (FPPS/GGPPS) is a key enzyme in the synthesis of isoprenic chains. Risedronate, a bisphosphonate containing nitrogen (N-BP), is a potent inhibitor of blood stage Plasmodium. Here, we show that P. falciparum parasites overexpressing FPPS/GGPPS are more resistant to risedronate, suggesting that this enzyme is an important target, and bisphosphonate analogues can be used as potential antimalarial drugs.
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Affiliation(s)
- Heloisa B Gabriel
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Mauro F Azevedo
- Departamento de Biociências, Universidade Federal de São Paulo, Santos, SP, Brazil
| | - Emília A Kimura
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Alejandro M Katzin
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brazil
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14
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Araujo RBD, Silva TM, Kaiser CS, Leite GF, Alonso D, Ribolla PEM, Wunderlich G. Independent regulation of Plasmodium falciparum rif gene promoters. Sci Rep 2018; 8:9332. [PMID: 29921926 PMCID: PMC6008437 DOI: 10.1038/s41598-018-27646-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 06/07/2018] [Indexed: 11/09/2022] Open
Abstract
All Plasmodium species express variant antigens which may mediate immune escape in the vertebrate host. In Plasmodium falciparum, the rif gene family encodes variant antigens which are partly exposed on the infected red blood cell surface and may function as virulence factors. Not all rif genes are expressed at the same time and it is unclear what controls rif gene expression. In this work, we addressed global rif transcription using plasmid vectors with two drug resistance markers, one controlled by a rif 5′ upstream region and the second by a constitutively active promoter. After spontaneous integration into the genome of one construct, we observed that the resistance marker controlled by the rif 5′ upstream region was expressed dependent on the applied drug pressure. Then, the global transcription of rif genes in these transfectants was compared in the presence or absence of drugs. The relative transcript quantities of all rif loci did not change profoundly between strains grown with or without drug. We conclude that either there is no crosstalk between rif loci or that the elusive system of allelic exclusion of rif gene transcription is not controlled by their 5′ upstream region alone.
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Affiliation(s)
- Rosana Beatriz Duque Araujo
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo - SP, 05508000, Brazil
| | - Tatiane Macedo Silva
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo - SP, 05508000, Brazil
| | - Charlotte Sophie Kaiser
- Institute of Animal Physiology, Schloßplatz 8, Westfälische Wilhelms Universität, Münster, Germany
| | - Gabriela Fernandes Leite
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo - SP, 05508000, Brazil
| | - Diego Alonso
- Department of Parasitology, IBB/IBTEC, State University of São Paulo, Botucatu, São Paulo, Brazil
| | | | - Gerhard Wunderlich
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo - SP, 05508000, Brazil.
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15
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Charnaud SC, Jonsdottir TK, Sanders PR, Bullen HE, Dickerman BK, Kouskousis B, Palmer CS, Pietrzak HM, Laumaea AE, Erazo AB, McHugh E, Tilley L, Crabb BS, Gilson PR. Spatial organization of protein export in malaria parasite blood stages. Traffic 2018; 19:605-623. [DOI: 10.1111/tra.12577] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 04/21/2018] [Accepted: 04/24/2018] [Indexed: 12/29/2022]
Affiliation(s)
| | - Thorey K. Jonsdottir
- Burnet Institute; Melbourne Australia
- Peter Doherty Institute for Infection and Immunity, University of Melbourne; Melbourne Australia
| | | | | | | | - Betty Kouskousis
- Burnet Institute; Melbourne Australia
- Monash Micro Imaging, Monash University; Melbourne Australia
| | - Catherine S. Palmer
- Burnet Institute; Melbourne Australia
- Monash Micro Imaging, Monash University; Melbourne Australia
| | | | | | | | - Emma McHugh
- Department of Biochemistry and Molecular Biology, University of Melbourne; Melbourne Australia
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology, University of Melbourne; Melbourne Australia
| | - Brendan S. Crabb
- Burnet Institute; Melbourne Australia
- Peter Doherty Institute for Infection and Immunity, University of Melbourne; Melbourne Australia
- Department of Microbiology, Monash University; Melbourne Australia
| | - Paul R. Gilson
- Burnet Institute; Melbourne Australia
- Department of Microbiology, Monash University; Melbourne Australia
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Zhang J, Yin K, Sun J, Gao J, Du Q, Li H, Qiu J. Direct and tunable modulation of protein levels in rice and wheat with a synthetic small molecule. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:472-481. [PMID: 28682500 PMCID: PMC5787845 DOI: 10.1111/pbi.12787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 06/24/2017] [Accepted: 07/03/2017] [Indexed: 06/07/2023]
Abstract
Direct control of protein level enables rapid and efficient analyses of gene functions in crops. Previously, we developed the RDDK-Shield1 (Shld1) system in the model plant Arabidopsis thaliana for direct modulation of protein stabilization using a synthetic small molecule. However, it was unclear whether this system is applicable to economically important crops. In this study, we show that the RDDK-Shld1 system enables rapid and tunable control of protein levels in rice and wheat. Accumulation of RDDK fusion proteins can be reversibly and spatio-temporally controlled by the synthetic small-molecule Shld1. Moreover, RDDK-Bar and RDDK-Pid3 fusions confer herbicide and rice blast resistance, respectively, in a Shld1-dependent manner. Therefore, the RDDK-Shld1 system provides a reversible and tunable technique for controlling protein functions and conditional expression of transgenes in crops.
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Affiliation(s)
- Jingbo Zhang
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Kangquan Yin
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Juan Sun
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Jinlan Gao
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Qiuli Du
- Department of Life Science and EngineeringJining UniversityQufuChina
- National Center for Soybean ImprovementNational Key Laboratory of Crop Genetics and Germplasm EnhancementNanjing Agricultural UniversityNanjingChina
| | - Huali Li
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
| | - Jin‐Long Qiu
- State Key Laboratory of Plant GenomicsInstitute of MicrobiologyChinese Academy of SciencesBeijingChina
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Knockdown of the Plasmodium falciparum SURFIN4.1 antigen leads to an increase of its cognate transcript. PLoS One 2017; 12:e0183129. [PMID: 28800640 PMCID: PMC5553854 DOI: 10.1371/journal.pone.0183129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 07/31/2017] [Indexed: 11/24/2022] Open
Abstract
The genome of the malaria parasite Plasmodium falciparum contains the surf gene family which encodes large transmembrane proteins of unknown function. While some surf alleles appear to be expressed in sexual stages, others occur in asexual blood stage forms and may be associated to virulence-associated processes and undergo transcriptional switching. We accessed the transcription of surf genes along multiple invasions by real time PCR. Based on the observation of persistent expression of gene surf4.1, we created a parasite line which expresses a conditionally destabilized SURFIN4.1 protein. Upon destabilization of the protein, no interference of parasite growth or morphological changes were detected. However, we observed a strong increase in the transcript quantities of surf4.1 and sometimes of other surf genes in knocked-down parasites. While this effect was reversible when SURFIN4.1 was stabilized again after a few days of destabilization, longer destabilization periods resulted in a transcriptional switch away from surf4.1. When we tested if a longer transcript half-life was responsible for increased transcript detection in SURFIN4.1 knocked-down parasites, no alteration was found compared to control parasite lines. This suggests a specific feedback of the expressed SURFIN protein to its transcript pointing to a novel type of regulation, inedited in Plasmodium.
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18
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Affiliation(s)
- George M. Burslem
- Departments of Molecular,
Cellular, and Developmental Biology, Chemistry, and Pharmacology, Yale University, 219 Prospect Street, New Haven, Connecticut 06511, United States
| | - Craig M. Crews
- Departments of Molecular,
Cellular, and Developmental Biology, Chemistry, and Pharmacology, Yale University, 219 Prospect Street, New Haven, Connecticut 06511, United States
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19
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Abstract
The target of rapamycin complex 1 (TORC1) pathway is a highly conserved signaling pathway across eukaryotes that integrates nutrient and stress signals to regulate the cellular growth rate and the transition into and maintenance of dormancy. The majority of the pathway's components, including the central TOR kinase, have been lost in the apicomplexan lineage, and it is unknown how these organisms detect and respond to nutrient starvation in its absence. Plasmodium falciparum encodes a putative ortholog of the RNA polymerase (Pol) III repressor Maf1, which has been demonstrated to modulate Pol III transcription in a TOR-dependent manner in a number of organisms. Here, we investigate the role of P. falciparum Maf1 (PfMaf1) in regulating RNA Pol III expression under conditions of nutrient starvation and other stresses. Using a transposon insertion mutant with an altered Maf1 expression profile, we demonstrated that proper Maf1 expression is necessary for survival of the dormancy-like state induced by prolonged amino acid starvation and is needed for full recovery from other stresses that slow or stall the parasite cell cycle. This Maf1 mutant is defective in the downregulation of pre-tRNA synthesis under nutrient-limiting conditions, indicating that the function of Maf1 as a stress-responsive regulator of structural RNA transcription is conserved in P. falciparum Recent work has demonstrated that parasites carrying artemisinin-resistant K13 alleles display an enhanced ability to recover from drug-induced growth retardation. We show that one such artemisinin-resistant line displays greater regulation of pre-tRNA expression and higher survival upon prolonged amino acid starvation, suggesting that overlapping, PfMaf1-associated pathways may regulate growth recovery from both artemisinin treatment and amino acid starvation.IMPORTANCE Eukaryote organisms sense changes in their environment and integrate this information through signaling pathways to activate response programs to ensure survival. The TOR pathway is a well-studied signaling pathway found throughout eukaryotes that is known to integrate a variety of signals to regulate organismal growth in response to starvation and other stresses. The human malaria parasite Plasmodium falciparum appears to have lost the TOR pathway over the course of evolution, and it is unclear how the parasite modulates its growth in response to starvation and drug treatment. Here, we show that Maf1, a protein regulated by TOR in other eukaryotes, plays an important role in maintaining the parasite's viability in the face of starvation and other forms of stress. This suggests that PfMaf1 is a component of a yet-to-be-described nutrient and stress response pathway.
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20
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Tools for attenuation of gene expression in malaria parasites. Int J Parasitol 2017; 47:385-398. [PMID: 28153780 DOI: 10.1016/j.ijpara.2016.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 09/15/2016] [Accepted: 11/28/2016] [Indexed: 12/30/2022]
Abstract
An understanding of the biology of Plasmodium parasites, which are the causative agents of the disease malaria, requires study of gene function. Various reverse genetic tools have been described for determining gene function. These tools can be broadly grouped as trans- and cis-acting. Trans-acting tools control gene functions through synthetic nucleic acid probe molecules matching the sequence of the gene of interest. Once delivered to the parasite, the probe engages with the mRNA of the target gene and attenuates its function. Cis-acting tools control gene function through elements introduced into the gene of interest by DNA transfection. The expression of the modified gene can be controlled using external agents, typically small molecule ligands. In this review, we discuss the strengths and weaknesses of these tools to guide researchers in selecting the appropriate tool for studies of gene function, and for guiding future refinements of these tools.
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Dickerman BK, Elsworth B, Cobbold SA, Nie CQ, McConville MJ, Crabb BS, Gilson PR. Identification of inhibitors that dually target the new permeability pathway and dihydroorotate dehydrogenase in the blood stage of Plasmodium falciparum. Sci Rep 2016; 6:37502. [PMID: 27874068 PMCID: PMC5118696 DOI: 10.1038/srep37502] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 10/28/2016] [Indexed: 12/22/2022] Open
Abstract
Plasmodium parasites are responsible for the devastating disease malaria that affects hundreds of millions of people each year. Blood stage parasites establish new permeability pathways (NPPs) in infected red blood cell membranes to facilitate the uptake of nutrients and removal of parasite waste products. Pharmacological inhibition of the NPPs is expected to lead to nutrient starvation and accumulation of toxic metabolites resulting in parasite death. Here, we have screened a curated library of antimalarial compounds, the MMV Malaria Box, identifying two compounds that inhibit NPP function. Unexpectedly, metabolic profiling suggested that both compounds also inhibit dihydroorotate dehydrogense (DHODH), which is required for pyrimidine synthesis and is a validated drug target in its own right. Expression of yeast DHODH, which bypasses the need for the parasite DHODH, increased parasite resistance to these compounds. These studies identify two potential candidates for therapeutic development that simultaneously target two essential pathways in Plasmodium, NPP and DHODH.
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Affiliation(s)
| | - Brendan Elsworth
- Burnet Institute, Melbourne, Victoria, Australia
- Monash University, Clayton, Victoria, Australia
| | - Simon A. Cobbold
- Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
| | | | - Malcolm J. McConville
- Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
| | - Brendan S. Crabb
- Burnet Institute, Melbourne, Victoria, Australia
- Monash University, Clayton, Victoria, Australia
- Bio21 Institute of Molecular Science and Biotechnology, University of Melbourne, Parkville, Victoria, Australia
| | - Paul R. Gilson
- Burnet Institute, Melbourne, Victoria, Australia
- Monash University, Clayton, Victoria, Australia
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Metabolomics-Based Screening of the Malaria Box Reveals both Novel and Established Mechanisms of Action. Antimicrob Agents Chemother 2016; 60:6650-6663. [PMID: 27572396 DOI: 10.1128/aac.01226-16] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/16/2016] [Indexed: 12/22/2022] Open
Abstract
High-throughput phenotypic screening of chemical libraries has resulted in the identification of thousands of compounds with potent antimalarial activity, although in most cases, the mechanism(s) of action of these compounds remains unknown. Here we have investigated the mode of action of 90 antimalarial compounds derived from the Malaria Box collection using high-coverage, untargeted metabolomics analysis. Approximately half of the tested compounds induced significant metabolic perturbations in in vitro cultures of Plasmodium falciparum In most cases, the metabolic profiles were highly correlated with known antimalarials, in particular artemisinin, the 4-aminoquinolines, or atovaquone. Select Malaria Box compounds also induced changes in intermediates in essential metabolic pathways, such as isoprenoid biosynthesis (i.e., 2-C-methyl-d-erythritol 2,4-cyclodiphosphate) and linolenic acid metabolism (i.e., traumatic acid). This study provides a comprehensive database of the metabolic perturbations induced by chemically diverse inhibitors and highlights the utility of metabolomics for triaging new lead compounds and defining specific modes of action, which will assist with the development and optimization of new antimalarial drugs.
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23
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Ebine K, Hirai M, Sakaguchi M, Yahata K, Kaneko O, Saito-Nakano Y. Plasmodium Rab5b is secreted to the cytoplasmic face of the tubovesicular network in infected red blood cells together with N-acylated adenylate kinase 2. Malar J 2016; 15:323. [PMID: 27316546 PMCID: PMC4912828 DOI: 10.1186/s12936-016-1377-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Accepted: 06/08/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rab5 GTPase regulates membrane trafficking between the plasma membrane and endosomes and harbours a conserved C-terminal isoprenyl modification that is necessary for membrane recruitment. Plasmodium falciparum encodes three Rab5 isotypes, and one of these, Rab5b (PfRab5b), lacks the C-terminal modification but possesses the N-terminal myristoylation motif. PfRab5b was reported to localize to the parasite periphery. However, the trafficking pathway regulated by PfRab5b is unknown. METHODS A complementation analysis of Rab5 isotypes was performed in Plasmodium berghei. A constitutively active PfRab5b mutant was expressed under the regulation of a ligand-dependent destabilization domain (DD)-tag system in P. falciparum. The localization of PfRab5b was evaluated after removing the ligand followed by selective permeabilization of the membrane with different detergents. Furthermore, P. falciparum N-terminally myristoylated adenylate kinase 2 (PfAK2) was co-expressed with PfRab5b, and trafficking of PfAK2 to the parasitophorous vacuole membrane was examined by confocal microscopy. RESULTS PfRab5b complemented the function of PbRab5b, however, the conventional C-terminally isoprenylated Rab5, PbRab5a or PbRab5c, did not. The constitutively active PfRab5b mutant localized to the cytosol of the parasite and the tubovesicular network (TVN), a region that extends from the parasitophorous vacuole membrane (PVM) in infected red blood cells (iRBCs). By removing the DD-ligand, parasite cytosolic PfRab5b signal disappeared and a punctate structure adjacent to the endoplasmic reticulum (ER) and parasite periphery accumulated. The peripheral PfRab5b was sensitive to extracellular proteolysis after treatment with streptolysin O, which selectively permeabilizes the red blood cell plasma membrane, indicating that PfRab5b localized on the iRBC cytoplasmic face of the TVN. Transport of PfAK2 to the PVM was abrogated by overexpression of PfRab5b, and PfAK2 accumulated in the punctate structure together with PfRab5b. CONCLUSION N-myristoylated Plasmodium Rab5b plays a role that is distinct from that of conventional mammalian Rab5 isotypes. PfRab5b localizes to a compartment close to the ER, translocated to the lumen of the organelle, and co-localizes with PfAK2. PfRab5b and PfAK2 are then transported to the TVN, and PfRab5b localizes on the iRBC cytoplasmic face of TVN. These data demonstrate that PfRab5b is transported from the parasite cytosol to TVN together with N-myristoylated PfAK2 via an uncharacterized membrane-trafficking pathway.
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Affiliation(s)
- Kazuo Ebine
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-Ku, Tokyo, Japan. .,Division of Cellular Dynamics, National Institute for Basic Biology, Okazaki, Aichi, Japan.
| | - Makoto Hirai
- Department of Molecular and Cellular Parasitology, Graduate School of Medicine, Juntendo University, Bunkyo-Ku, Tokyo, Japan.,Department of Parasitology, Graduate School of Medicine, Gunma University, Gunma, Japan
| | - Miako Sakaguchi
- Central Laboratory, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Nagasaki, Japan
| | - Kazuhide Yahata
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Nagasaki, Japan
| | - Osamu Kaneko
- Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Nagasaki, Japan
| | - Yumiko Saito-Nakano
- Department of Parasitology, National Institute of Infectious Diseases, Shinjuku-Ku, Tokyo, Japan.
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24
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Gabriel HB, de Azevedo MF, Palmisano G, Wunderlich G, Kimura EA, Katzin AM, Alves JMP. Single-target high-throughput transcription analyses reveal high levels of alternative splicing present in the FPPS/GGPPS from Plasmodium falciparum. Sci Rep 2015; 5:18429. [PMID: 26688062 PMCID: PMC4685265 DOI: 10.1038/srep18429] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 11/17/2015] [Indexed: 11/26/2022] Open
Abstract
Malaria is a tropical disease with significant morbidity and mortality. A better understanding of the metabolism of its most important etiological agent, Plasmodium falciparum, is paramount to the development of better treatment and other mitigation measures. Farnesyldiphosphate synthase/geranylgeranyldiphosphate synthase (FPPS/GGPPS) is a key enzyme in the synthesis of isoprenic chains present in many essential structures. In P. falciparum, as well as a handful of other organisms, FPPS/GGPPS has been shown to be a bifunctional enzyme. By genetic tagging and microscopy, we observed a changing localization of FPPS/GGPPS in blood stage parasites. Given the great importance of alternative splicing and other transcriptional phenomena in gene regulation and the generation of protein diversity, we have investigated the processing of the FPPS/GGPPS transcript in P. falciparum by high-throughput sequencing methods in four time-points along the intraerythrocytic cycle of P. falciparum. We have identified levels of transcript diversity an order of magnitude higher than previously observed in this organism, as well as a few stage-specific splicing events. Our data suggest that alternative splicing in P. falciparum is an important feature for gene regulation and the generation of protein diversity.
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Affiliation(s)
- Heloisa B Gabriel
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Mauro F de Azevedo
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Giuseppe Palmisano
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Gerhard Wunderlich
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Emília A Kimura
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Alejandro M Katzin
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - João M P Alves
- Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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25
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Hallée S, Richard D. Evidence that the Malaria Parasite Plasmodium falciparum Putative Rhoptry Protein 2 Localizes to the Golgi Apparatus throughout the Erythrocytic Cycle. PLoS One 2015; 10:e0138626. [PMID: 26375591 PMCID: PMC4574476 DOI: 10.1371/journal.pone.0138626] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 08/31/2015] [Indexed: 11/28/2022] Open
Abstract
Invasion of a red blood cell by Plasmodium falciparum merozoites is an essential step in the malaria lifecycle. Several of the proteins involved in this process are stored in the apical complex of the merozoite, a structure containing secretory organelles that are released at specific times during invasion. The molecular players involved in erythrocyte invasion thus represent potential key targets for both therapeutic and vaccine-based strategies to block parasite development. In our quest to identify and characterize new effectors of invasion, we investigated the P. falciparum homologue of a P. berghei protein putatively localized to the rhoptries, the Putative rhoptry protein 2 (PbPRP2). We show that in P. falciparum, the protein colocalizes extensively with the Golgi apparatus across the asexual erythrocytic cycle. Furthermore, imaging of merozoites caught at different times during invasion show that PfPRP2 is not secreted during the process instead staying associated with the Golgi apparatus. Our evidence therefore suggests that PfPRP2 is a Golgi protein and that it is likely not a direct effector in the process of merozoite invasion.
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Affiliation(s)
- Stéphanie Hallée
- Centre de recherche en infectiologie, CHU-Université Laval, Quebec City, Quebec, Canada
| | - Dave Richard
- Centre de recherche en infectiologie, CHU-Université Laval, Quebec City, Quebec, Canada
- * E-mail:
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26
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de Koning-Ward TF, Gilson PR, Crabb BS. Advances in molecular genetic systems in malaria. Nat Rev Microbiol 2015; 13:373-87. [DOI: 10.1038/nrmicro3450] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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27
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Siciliano G, Alano P. Enlightening the malaria parasite life cycle: bioluminescent Plasmodium in fundamental and applied research. Front Microbiol 2015; 6:391. [PMID: 26029172 PMCID: PMC4426725 DOI: 10.3389/fmicb.2015.00391] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 04/16/2015] [Indexed: 12/31/2022] Open
Abstract
The unicellular protozoan parasites of the genus Plasmodium impose on human health worldwide the enormous burden of malaria. The possibility to genetically modify several species of malaria parasites represented a major advance in the possibility to elucidate their biology and is now turning laboratory lines of transgenic Plasmodium into precious weapons to fight malaria. Amongst the various genetically modified plasmodia, transgenic parasite lines expressing bioluminescent reporters have been essential to unveil mechanisms of parasite gene expression and to develop in vivo imaging approaches in mouse malaria models. Mainly the human malaria parasite Plasmodium falciparum and the rodent parasite P. berghei have been engineered to express bioluminescent reporters in almost all the developmental stages of the parasite along its complex life cycle between the insect and the vertebrate hosts. Plasmodium lines expressing conventional and improved luciferase reporters are now gaining a central role to develop cell based assays in the much needed search of new antimalarial drugs and to open innovative approaches for both fundamental and applied research in malaria.
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Affiliation(s)
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di SanitàRome, Italy
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28
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Squalestatin is an inhibitor of carotenoid biosynthesis in Plasmodium falciparum. Antimicrob Agents Chemother 2015; 59:3180-8. [PMID: 25779575 DOI: 10.1128/aac.04500-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 03/09/2015] [Indexed: 01/01/2023] Open
Abstract
The increasing resistance of malaria parasites to almost all available drugs calls for the characterization of novel targets and the identification of new compounds. Carotenoids are polyisoprenoids from plants, algae, and some bacteria, and they are biosynthesized by Plasmodium falciparum but not by mammalian cells. Biochemical and reverse genetics approaches were applied to demonstrate that phytoene synthase (PSY) is a key enzyme for carotenoid biosynthesis in P. falciparum and is essential for intraerythrocytic growth. The known PSY inhibitor squalestatin reduces biosynthesis of phytoene and kills parasites during the intraerythrocytic cycle. PSY-overexpressing parasites showed increased biosynthesis of phytoene and its derived product phytofluene and presented a squalestatin-resistant phenotype, suggesting that this enzyme is the primary target of action of this drug in the parasite.
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29
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Plasmodium falciparum transfected with ultra bright NanoLuc luciferase offers high sensitivity detection for the screening of growth and cellular trafficking inhibitors. PLoS One 2014; 9:e112571. [PMID: 25392998 PMCID: PMC4231029 DOI: 10.1371/journal.pone.0112571] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 10/08/2014] [Indexed: 11/19/2022] Open
Abstract
Drug discovery is a key part of malaria control and eradication strategies, and could benefit from sensitive and affordable assays to quantify parasite growth and to help identify the targets of potential anti-malarial compounds. Bioluminescence, achieved through expression of exogenous luciferases, is a powerful tool that has been applied in studies of several aspects of parasite biology and high throughput growth assays. We have expressed the new reporter NanoLuc (Nluc) luciferase in Plasmodium falciparum and showed it is at least 100 times brighter than the commonly used firefly luciferase. Nluc brightness was explored as a means to achieve a growth assay with higher sensitivity and lower cost. In addition we attempted to develop other screening assays that may help interrogate libraries of inhibitory compounds for their mechanism of action. To this end parasites were engineered to express Nluc in the cytoplasm, the parasitophorous vacuole that surrounds the intraerythrocytic parasite or exported to the red blood cell cytosol. As proof-of-concept, these parasites were used to develop functional screening assays for quantifying the effects of Brefeldin A, an inhibitor of protein secretion, and Furosemide, an inhibitor of new permeation pathways used by parasites to acquire plasma nutrients.
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30
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Webster WAJ, McFadden GI. From the genome to the phenome: tools to understand the basic biology of Plasmodium falciparum. J Eukaryot Microbiol 2014; 61:655-71. [PMID: 25227912 DOI: 10.1111/jeu.12176] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/01/2014] [Accepted: 09/02/2014] [Indexed: 11/30/2022]
Abstract
Malaria plagues one out of every 30 humans and contributes to almost a million deaths, and the problem could worsen. Our current therapeutic options are compromised by emerging resistance by the parasite to our front line drugs. It is thus imperative to better understand the basic biology of the parasite and develop novel drugs to stem this disease. The most facile approach to analyse a gene's function is to remove it from the genome or inhibit its activity. Although genetic manipulation of the human malaria parasite Plasmodium falciparum is a relatively standard procedure, there is no optimal method to perturb genes essential to the intraerythrocytic development cycle--the part of the life cycle that produces the clinical manifestation of malaria. This is a severe impediment to progress because the phenotype we wish to study is exactly the one that is so elusive. In the absence of any utilitarian way to conditionally delete essential genes, we are prevented from investigating the parasite's most vulnerable points. This review aims to focus on the development of tools identifying essential genes of P. falciparum and our ability to elicit phenotypic mutation.
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Affiliation(s)
- Wesley A J Webster
- Centre for Regional and Rural Futures, School of Life and Environmental Sciences, Deakin University, Burwood, 3125, Victoria, Australia; Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Melbourne, 3010, Victoria, Australia
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31
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Tarr SJ, Moon RW, Hardege I, Osborne AR. A conserved domain targets exported PHISTb family proteins to the periphery of Plasmodium infected erythrocytes. Mol Biochem Parasitol 2014; 196:29-40. [PMID: 25106850 PMCID: PMC4165601 DOI: 10.1016/j.molbiopara.2014.07.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 07/24/2014] [Accepted: 07/28/2014] [Indexed: 11/19/2022]
Abstract
Multiple P. falciparum PHISTb proteins localise to the erythrocyte periphery. Solubility profiling indicates that these proteins associate with the red cell cytoskeleton. The PRESAN domain and a preceding N-terminal sequence is a novel targeting domain. A protein targeted to the red cell periphery is essential for parasite survival. P. knowlesi and P. vivax homologous domains also confer similar localisation.
During blood-stage infection, malaria parasites export numerous proteins to the host erythrocyte. The Poly-Helical Interspersed Sub-Telomeric (PHIST) proteins are an exported family that share a common ‘PRESAN’ domain, and include numerous members in Plasmodium falciparum, Plasmodium vivax and Plasmodium knowlesi. In P. falciparum, PHIST proteins have been implicated in protein trafficking and intercellular communication. A number of PHIST proteins are essential for parasite survival. Here, we identify nine members of the PHISTb sub-class of PHIST proteins, including one protein known to be essential for parasite survival, that localise to the erythrocyte periphery. These proteins have solubility characteristics consistent with their association with the erythrocyte cytoskeleton. Together, an extended PRESAN domain, comprising the PRESAN domain and preceding sequence, form a novel targeting-domain that is sufficient to localise a protein to the erythrocyte periphery. We validate the role of this domain in RESA, thus identifying a cytoskeleton-binding domain in RESA that functions independently of its known spectrin-binding domain. Our data suggest that some PHISTb proteins may act as cross-linkers of the erythrocyte cytoskeleton. We also show for the first time that peripherally-localised PHISTb proteins are encoded in genomes of P. knowlesi and vivax indicating a conserved role for the extended PRESAN domain of these proteins in targeting to the erythrocyte periphery.
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Affiliation(s)
- Sarah J Tarr
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, UK
| | - Robert W Moon
- Division of Parasitology, MRC National Institute for Medical Research, London, UK
| | - Iris Hardege
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, UK
| | - Andrew R Osborne
- Institute of Structural and Molecular Biology, Division of Biosciences, Birkbeck and University College London, London, UK.
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32
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Advantages and disadvantages of conditional systems for characterization of essential genes in Toxoplasma gondii. Parasitology 2014; 141:1390-8. [PMID: 24926834 DOI: 10.1017/s0031182014000559] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The dissection of apicomplexan biology has been highly influenced by the genetic tools available for manipulation of parasite DNA. Here, we describe different techniques available for the generation of conditional mutants. Comparison of the advantages and disadvantages of the three most commonly used regulation systems: the tetracycline inducible system, the regulation of protein stability and site-specific recombination are discussed. Using some previously described examples we explore some of the pitfalls involved in gene-function analysis using these systems that can lead to wrong or over-interpretation of phenotypes. We will also mention different options to standardize the application of these techniques for the characterization of gene function in high-throughput.
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Park A, Won ST, Pentecost M, Bartkowski W, Lee B. CRISPR/Cas9 allows efficient and complete knock-in of a destabilization domain-tagged essential protein in a human cell line, allowing rapid knockdown of protein function. PLoS One 2014; 9:e95101. [PMID: 24743236 PMCID: PMC3990584 DOI: 10.1371/journal.pone.0095101] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 03/21/2014] [Indexed: 12/26/2022] Open
Abstract
Although modulation of protein levels is an important tool for study of protein function, it is difficult or impossible to knockdown or knockout genes that are critical for cell growth or viability. For such genes, a conditional knockdown approach would be valuable. The FKBP protein-based destabilization domain (DD)-tagging approach, which confers instability to the tagged protein in the absence of the compound Shield-1, has been shown to provide rapid control of protein levels determined by Shield-1 concentration. Although a strategy to knock-in DD-tagged protein at the endogenous loci has been employed in certain parasite studies, partly due to the relative ease of knock-in as a result of their mostly haploid lifecycles, this strategy has not been demonstrated in diploid or hyperploid mammalian cells due to the relative difficulty of achieving complete knock-in in all alleles. The recent advent of CRISPR/Cas9 homing endonuclease-mediated targeted genome cleavage has been shown to allow highly efficient homologous recombination at the targeted locus. We therefore assessed the feasibility of using CRISPR/Cas9 to achieve complete knock-in to DD-tag the essential gene Treacher Collins-Franceschetti syndrome 1 (TCOF1) in human 293T cells. Using a double antibiotic selection strategy to select clones with at least two knock-in alleles, we obtained numerous complete knock-in clones within three weeks of initial transfection. DD-TCOF1 expression in the knock-in cells was Shield-1 concentration-dependent, and removal of Shield-1 resulted in destabilization of DD-TCOF1 over the course of hours. We further confirmed that the tagged TCOF1 retained the nucleolar localization of the wild-type untagged protein, and that destabilization of DD-TCOF1 resulted in impaired cell growth, as expected for a gene implicated in ribosome biogenesis. CRISPR/Cas9-mediated homologous recombination to completely knock-in a DD tag likely represents a generalizable and efficient strategy to achieve rapid modulation of protein levels in mammalian cells.
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Affiliation(s)
- Arnold Park
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Sohui T Won
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Mickey Pentecost
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Wojciech Bartkowski
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Benhur Lee
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America; Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
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Yap A, Azevedo MF, Gilson PR, Weiss GE, O'Neill MT, Wilson DW, Crabb BS, Cowman AF. Conditional expression of apical membrane antigen 1 in Plasmodium falciparum shows it is required for erythrocyte invasion by merozoites. Cell Microbiol 2014; 16:642-56. [PMID: 24571085 PMCID: PMC4231980 DOI: 10.1111/cmi.12287] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 02/23/2014] [Accepted: 02/24/2014] [Indexed: 11/30/2022]
Abstract
Malaria is caused by obligate intracellular parasites, of which Plasmodium falciparum is the most lethal species. In humans, P. falciparum merozoites (invasive forms of the parasite) employ a host of parasite proteins to rapidly invade erythrocytes. One of these is the P. falciparum apical membrane antigen 1 (PfAMA1) which forms a complex with rhoptry neck proteins at the tight junction. Here, we have placed the Pfama1 gene under conditional control using dimerizable Cre recombinase (DiCre) in P. falciparum. DiCre-mediated excision of the loxP-flanked Pfama1 gene results in approximately 80% decreased expression of the protein within one intraerythrocytic growth cycle. This reduces growth by 40%, due to decreased invasion efficiency characterized by a post-invasion defect in sealing of the parasitophorous vacuole. These results show that PfAMA1 is an essential protein for merozoite invasion in P. falciparum and either directly or indirectly plays a role in resealing of the red blood cell at the posterior end of the invasion event.
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Affiliation(s)
- Alan Yap
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Vic., 3052, Australia
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Prommana P, Uthaipibull C, Wongsombat C, Kamchonwongpaisan S, Yuthavong Y, Knuepfer E, Holder AA, Shaw PJ. Inducible knockdown of Plasmodium gene expression using the glmS ribozyme. PLoS One 2013; 8:e73783. [PMID: 24023691 PMCID: PMC3758297 DOI: 10.1371/journal.pone.0073783] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 07/23/2013] [Indexed: 01/07/2023] Open
Abstract
Conventional reverse genetic approaches for study of Plasmodium malaria parasite gene function are limited, or not applicable. Hence, new inducible systems are needed. Here we describe a method to control P. falciparum gene expression in which target genes bearing a glmS ribozyme in the 3' untranslated region are efficiently knocked down in transgenic P. falciparum parasites in response to glucosamine inducer. Using reporter genes, we show that the glmS ribozyme cleaves reporter mRNA in vivo leading to reduction in mRNA expression following glucosamine treatment. Glucosamine-induced ribozyme activation led to efficient reduction of reporter protein, which could be rapidly reversed by removing the inducer. The glmS ribozyme was validated as a reverse-genetic tool by integration into the essential gene and antifolate drug target dihydrofolate reductase-thymidylate synthase (PfDHFR-TS). Glucosamine treatment of transgenic parasites led to rapid and efficient knockdown of PfDHFR-TS mRNA and protein. PfDHFR-TS knockdown led to a growth/arrest mutant phenotype and hypersensitivity to pyrimethamine. The glmS ribozyme may thus be a tool for study of essential genes in P. falciparum and other parasite species amenable to transfection.
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Affiliation(s)
- Parichat Prommana
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Chairat Uthaipibull
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Chayaphat Wongsombat
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Sumalee Kamchonwongpaisan
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Yongyuth Yuthavong
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
| | - Ellen Knuepfer
- Division of Parasitology, MRC National Institute for Medical Research, London, United Kingdom
| | - Anthony A. Holder
- Division of Parasitology, MRC National Institute for Medical Research, London, United Kingdom
| | - Philip J. Shaw
- National Center for Genetic Engineering and Biotechnology (BIOTEC), Khlong Nueng, Khlong Luang, Pathum Thani, Thailand
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Inhibition of Plasmodium falciparum CDPK1 by conditional expression of its J-domain demonstrates a key role in schizont development. Biochem J 2013; 452:433-41. [PMID: 23548171 DOI: 10.1042/bj20130124] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PfCDPK1 [Plasmodium falciparum CDPK1 (calcium-dependent protein kinase 1)] is highly expressed in parasite asexual blood and mosquito stages. Its role is still poorly understood, but unsuccessful gene knockout attempts suggest that it is essential for parasite replication and/or RBC (red blood cell) invasion. In the present study, by tagging endogenous CDPK1 with GFP (green fluorescent protein), we demonstrate that CDPK1 localizes to the parasite plasma membrane of replicating and invasive forms as well as very young intracellular parasites and does not appear to be exported into RBCs. Although a knockdown of endogenous CDPK1 was achieved using a destabilization domain, parasites tolerated reduced expression without displaying a phenotype. Because of this, the PfCDPK1 auto-inhibitory J (junction) domain was explored as a means of achieving inducible and specific inhibition. Under in vitro conditions, a fusion protein comprising a J-GFP fusion specifically bound to PfCDPK1 and inhibited its activity. This fusion protein was conditionally expressed in P. falciparum asexual blood stages under the regulation of a DD (destabilization domain) (J-GFP-DD). We demonstrate that J-GFP-DD binds to CDPK1 and that this results in the arrest of parasite development late in the cell cycle during early schizogony. These data point to an early schizont function for PfCDPK1 and demonstrate that conditionally expressing auto-inhibitory regions can be an effective way to address the function of Plasmodium enzymes.
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Pino P. From technology to biology: a malaria genetic toolbox for the functional dissection of essential genes. Mol Microbiol 2013; 88:650-4. [DOI: 10.1111/mmi.12232] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2013] [Indexed: 11/28/2022]
Affiliation(s)
- Paco Pino
- Department of Microbiology and Molecular Medicine; CMU; Faculty of Medicine; University of Geneva; Rue Michel-Servet 1; CH-1211; Geneva 4; Switzerland
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