1
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Diffendall G, Scherf A. Deciphering the Plasmodium falciparum perinuclear var gene expression site. Trends Parasitol 2024; 40:707-716. [PMID: 38910098 DOI: 10.1016/j.pt.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 06/03/2024] [Accepted: 06/03/2024] [Indexed: 06/25/2024]
Abstract
The protozoan parasite Plasmodium falciparum, responsible for the deadliest form of human malaria, employs antigenic variation via monoallelic expression as a key survival strategy. The selective activation of one out of the 60-member var gene family is key to understanding the parasite's ability to cause severe disease and evade the host immune response. var gene activation is initiated by its relocation to a specialized expression site. While the perinuclear expression site (PES) plays a crucial role in enabling the expression of a single allele, the characteristics of this PES remain largely obscure. Recent breakthroughs in genome editing tools and the discovery of regulatory noncoding RNAs have shed light on this intriguing biological feature, offering significant insights into the mechanisms of pathogen virulence.
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Affiliation(s)
- Gretchen Diffendall
- Institut Pasteur, Universite Paris Cité, INSERM U1201, CNRS EMR9195, Paris, France
| | - Artur Scherf
- Institut Pasteur, Universite Paris Cité, INSERM U1201, CNRS EMR9195, Paris, France.
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2
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Diffendall G, Claes A, Barcons-Simon A, Nyarko P, Dingli F, Santos MM, Loew D, Claessens A, Scherf A. RNA polymerase III is involved in regulating Plasmodium falciparum virulence. eLife 2024; 13:RP95879. [PMID: 38921824 PMCID: PMC11208047 DOI: 10.7554/elife.95879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2024] Open
Abstract
While often undetected and untreated, persistent seasonal asymptomatic malaria infections remain a global public health problem. Despite the presence of parasites in the peripheral blood, no symptoms develop. Disease severity is correlated with the levels of infected red blood cells (iRBCs) adhering within blood vessels. Changes in iRBC adhesion capacity have been linked to seasonal asymptomatic malaria infections, however how this is occurring is still unknown. Here, we present evidence that RNA polymerase III (RNA Pol III) transcription in Plasmodium falciparum is downregulated in field isolates obtained from asymptomatic individuals during the dry season. Through experiments with in vitro cultured parasites, we have uncovered an RNA Pol III-dependent mechanism that controls pathogen proliferation and expression of a major virulence factor in response to external stimuli. Our findings establish a connection between P. falciparum cytoadhesion and a non-coding RNA family transcribed by Pol III. Additionally, we have identified P. falciparum Maf1 as a pivotal regulator of Pol III transcription, both for maintaining cellular homeostasis and for responding adaptively to external signals. These results introduce a novel perspective that contributes to our understanding of P. falciparum virulence. Furthermore, they establish a connection between this regulatory process and the occurrence of seasonal asymptomatic malaria infections.
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Affiliation(s)
- Gretchen Diffendall
- Institut Pasteur, Universite Paris CitéParisFrance
- Institut Pasteur, Sorbonne Université Ecole doctorale Complexité du VivantParisFrance
| | | | - Anna Barcons-Simon
- Institut Pasteur, Universite Paris CitéParisFrance
- Institut Pasteur, Sorbonne Université Ecole doctorale Complexité du VivantParisFrance
- Institut Pasteur, Biomedical Center, Division of Physiological Chemistry, Faculty of Medicine, Ludwig-Maximilians-Universität MünchenMunichGermany
| | - Prince Nyarko
- Institut Pasteur, Laboratory of Pathogen-Host Interaction (LPHI), CNRS, University of MontpellierMontpellierFrance
| | - Florent Dingli
- Institut Pasteur, Institut Curie, PSL Research University, Centre de Recherche, CurieCoreTech Mass Spectrometry ProteomicsParisFrance
| | - Miguel M Santos
- Institut Pasteur, Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de LisboaLisboaPortugal
| | - Damarys Loew
- Institut Pasteur, Institut Curie, PSL Research University, Centre de Recherche, CurieCoreTech Mass Spectrometry ProteomicsParisFrance
| | - Antoine Claessens
- Institut Pasteur, Laboratory of Pathogen-Host Interaction (LPHI), CNRS, University of MontpellierMontpellierFrance
- Institut Pasteur, LPHI, MIVEGEC, CNRS, INSERM, University of MontpellierMontpellierFrance
| | - Artur Scherf
- Institut Pasteur, Universite Paris CitéParisFrance
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3
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Hviid L, Jensen AR, Deitsch KW. PfEMP1 and var genes - Still of key importance in Plasmodium falciparum malaria pathogenesis and immunity. ADVANCES IN PARASITOLOGY 2024; 125:53-103. [PMID: 39095112 DOI: 10.1016/bs.apar.2024.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
The most severe form of malaria, caused by infection with Plasmodium falciparum parasites, continues to be an important cause of human suffering and poverty. The P. falciparum erythrocyte membrane protein 1 (PfEMP1) family of clonally variant antigens, which mediates the adhesion of infected erythrocytes to the vascular endothelium in various tissues and organs, is a central component of the pathogenesis of the disease and a key target of the acquired immune response to malaria. Much new knowledge has accumulated since we published a systematic overview of the PfEMP1 family almost ten years ago. In this chapter, we therefore aim to summarize research progress since 2015 on the structure, function, regulation etc. of this key protein family of arguably the most important human parasite. Recent insights regarding PfEMP1-specific immune responses and PfEMP1-specific vaccination against malaria, as well as an outlook for the coming years are also covered.
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Affiliation(s)
- Lars Hviid
- Centre for translational Medicine and Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
| | - Anja R Jensen
- Centre for translational Medicine and Parasitology, Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Kirk W Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, United States
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4
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Abstract
Plasmodium falciparum, the human malaria parasite, infects two hosts and various cell types, inducing distinct morphological and physiological changes in the parasite in response to different environmental conditions. These variations required the parasite to adapt and develop elaborate molecular mechanisms to ensure its spread and transmission. Recent findings have significantly improved our understanding of the regulation of gene expression in P. falciparum. Here, we provide an up-to-date overview of technologies used to highlight the transcriptomic adjustments occurring in the parasite throughout its life cycle. We also emphasize the complementary and complex epigenetic mechanisms regulating gene expression in malaria parasites. This review concludes with an outlook on the chromatin architecture, the remodeling systems, and how this 3D genome organization is critical in various biological processes.
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Affiliation(s)
- Thomas Hollin
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California, USA;
| | - Zeinab Chahine
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California, USA;
| | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, California, USA;
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5
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Batugedara G, Lu XM, Hristov B, Abel S, Chahine Z, Hollin T, Williams D, Wang T, Cort A, Lenz T, Thompson TA, Prudhomme J, Tripathi AK, Xu G, Cudini J, Dogga S, Lawniczak M, Noble WS, Sinnis P, Le Roch KG. Novel insights into the role of long non-coding RNA in the human malaria parasite, Plasmodium falciparum. Nat Commun 2023; 14:5086. [PMID: 37607941 PMCID: PMC10444892 DOI: 10.1038/s41467-023-40883-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 08/10/2023] [Indexed: 08/24/2023] Open
Abstract
The complex life cycle of Plasmodium falciparum requires coordinated gene expression regulation to allow host cell invasion, transmission, and immune evasion. Increasing evidence now suggests a major role for epigenetic mechanisms in gene expression in the parasite. In eukaryotes, many lncRNAs have been identified to be pivotal regulators of genome structure and gene expression. To investigate the regulatory roles of lncRNAs in P. falciparum we explore the intergenic lncRNA distribution in nuclear and cytoplasmic subcellular locations. Using nascent RNA expression profiles, we identify a total of 1768 lncRNAs, of which 718 (~41%) are novels in P. falciparum. The subcellular localization and stage-specific expression of several putative lncRNAs are validated using RNA-FISH. Additionally, the genome-wide occupancy of several candidate nuclear lncRNAs is explored using ChIRP. The results reveal that lncRNA occupancy sites are focal and sequence-specific with a particular enrichment for several parasite-specific gene families, including those involved in pathogenesis and sexual differentiation. Genomic and phenotypic analysis of one specific lncRNA demonstrate its importance in sexual differentiation and reproduction. Our findings bring a new level of insight into the role of lncRNAs in pathogenicity, gene regulation and sexual differentiation, opening new avenues for targeted therapeutic strategies against the deadly malaria parasite.
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Affiliation(s)
- Gayani Batugedara
- Department of Molecular Cell and Systems Biology, University of California Riverside, Riverside, CA, 92521, USA
| | - Xueqing M Lu
- Department of Molecular Cell and Systems Biology, University of California Riverside, Riverside, CA, 92521, USA
| | - Borislav Hristov
- Department of Genome Sciences, University of Washington, Seattle, WA, 98195-5065, USA
| | - Steven Abel
- Department of Molecular Cell and Systems Biology, University of California Riverside, Riverside, CA, 92521, USA
| | - Zeinab Chahine
- Department of Molecular Cell and Systems Biology, University of California Riverside, Riverside, CA, 92521, USA
| | - Thomas Hollin
- Department of Molecular Cell and Systems Biology, University of California Riverside, Riverside, CA, 92521, USA
| | - Desiree Williams
- Department of Molecular Cell and Systems Biology, University of California Riverside, Riverside, CA, 92521, USA
| | - Tina Wang
- Department of Molecular Cell and Systems Biology, University of California Riverside, Riverside, CA, 92521, USA
| | - Anthony Cort
- Department of Molecular Cell and Systems Biology, University of California Riverside, Riverside, CA, 92521, USA
| | - Todd Lenz
- Department of Molecular Cell and Systems Biology, University of California Riverside, Riverside, CA, 92521, USA
| | - Trevor A Thompson
- Department of Molecular Cell and Systems Biology, University of California Riverside, Riverside, CA, 92521, USA
| | - Jacques Prudhomme
- Department of Molecular Cell and Systems Biology, University of California Riverside, Riverside, CA, 92521, USA
| | - Abhai K Tripathi
- Department of Molecular Microbiology and Immunology and the Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Guoyue Xu
- Department of Molecular Microbiology and Immunology and the Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | | | - Sunil Dogga
- Wellcome Sanger Institute, Hinxton, CB10 1SA, UK
| | | | | | - Photini Sinnis
- Department of Molecular Microbiology and Immunology and the Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Karine G Le Roch
- Department of Molecular Cell and Systems Biology, University of California Riverside, Riverside, CA, 92521, USA.
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6
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Barcons-Simon A, Carrington M, Siegel TN. Decoding the impact of nuclear organization on antigenic variation in parasites. Nat Microbiol 2023; 8:1408-1418. [PMID: 37524976 DOI: 10.1038/s41564-023-01424-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 06/13/2023] [Indexed: 08/02/2023]
Abstract
Antigenic variation as a strategy to evade the host adaptive immune response has evolved in divergent pathogens. Antigenic variation involves restricted, and often mutually exclusive, expression of dominant antigens and a periodic switch in antigen expression during infection. In eukaryotes, nuclear compartmentalization, including three-dimensional folding of the genome and physical separation of proteins in compartments or condensates, regulates mutually exclusive gene expression and chromosomal translocations. In this Review, we discuss the impact of nuclear organization on antigenic variation in the protozoan pathogens Trypanosoma brucei and Plasmodium falciparum. In particular, we highlight the relevance of nuclear organization in both mutually exclusive antigen expression and genome stability, which underlie antigenic variation.
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Affiliation(s)
- Anna Barcons-Simon
- Division of Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
- Biomedical Center, Division of Physiological Chemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - T Nicolai Siegel
- Division of Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.
- Biomedical Center, Division of Physiological Chemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.
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7
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Thompson TA, Chahine Z, Le Roch KG. The role of long noncoding RNAs in malaria parasites. Trends Parasitol 2023; 39:517-531. [PMID: 37121862 DOI: 10.1016/j.pt.2023.03.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/16/2023] [Accepted: 03/18/2023] [Indexed: 05/02/2023]
Abstract
The human malaria parasites, including Plasmodium falciparum, persist as a major cause of global morbidity and mortality. The recent stalling of progress toward malaria elimination substantiates a need for novel interventions. Controlled gene expression is central to the parasite's numerous life cycle transformations and adaptation. With few specific transcription factors (TFs) identified, crucial roles for chromatin states and epigenetics in parasite transcription have become evident. Although many chromatin-modifying enzymes are known, less is known about which factors mediate their impacts on transcriptional variation. Like those of higher eukaryotes, long noncoding RNAs (lncRNAs) have recently been shown to have integral roles in parasite gene regulation. This review aims to summarize recent developments and key findings on the role of lncRNAs in P. falciparum.
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Affiliation(s)
- Trevor A Thompson
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - Zeinab Chahine
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA.
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8
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Wichers-Misterek JS, Krumkamp R, Held J, von Thien H, Wittmann I, Höppner YD, Ruge JM, Moser K, Dara A, Strauss J, Esen M, Fendel R, Sulyok Z, Jeninga MD, Kremsner PG, Sim BKL, Hoffman SL, Duffy MF, Otto TD, Gilberger TW, Silva JC, Mordmüller B, Petter M, Bachmann A. The exception that proves the rule: Virulence gene expression at the onset of Plasmodium falciparum blood stage infections. PLoS Pathog 2023; 19:e1011468. [PMID: 37384799 DOI: 10.1371/journal.ppat.1011468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 06/07/2023] [Indexed: 07/01/2023] Open
Abstract
Controlled human malaria infections (CHMI) are a valuable tool to study parasite gene expression in vivo under defined conditions. In previous studies, virulence gene expression was analyzed in samples from volunteers infected with the Plasmodium falciparum (Pf) NF54 isolate, which is of African origin. Here, we provide an in-depth investigation of parasite virulence gene expression in malaria-naïve European volunteers undergoing CHMI with the genetically distinct Pf 7G8 clone, originating in Brazil. Differential expression of var genes, encoding major virulence factors of Pf, PfEMP1s, was assessed in ex vivo parasite samples as well as in parasites from the in vitro cell bank culture that was used to generate the sporozoites (SPZ) for CHMI (Sanaria PfSPZ Challenge (7G8)). We report broad activation of mainly B-type subtelomeric located var genes at the onset of a 7G8 blood stage infection in naïve volunteers, mirroring the NF54 expression study and suggesting that the expression of virulence-associated genes is generally reset during transmission from the mosquito to the human host. However, in 7G8 parasites, we additionally detected a continuously expressed single C-type variant, Pf7G8_040025600, that was most highly expressed in both pre-mosquito cell bank and volunteer samples, suggesting that 7G8, unlike NF54, maintains expression of some previously expressed var variants during transmission. This suggests that in a new host, the parasite may preferentially express the variants that previously allowed successful infection and transmission. Trial registration: ClinicalTrials.gov - NCT02704533; 2018-004523-36.
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Affiliation(s)
- Jan Stephan Wichers-Misterek
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Ralf Krumkamp
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Hamburg/Borstel/Lübeck/Riems, Germany
| | - Jana Held
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Heidrun von Thien
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Irene Wittmann
- Institute of Microbiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Yannick Daniel Höppner
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Hamburg/Borstel/Lübeck/Riems, Germany
| | - Julia M Ruge
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Hamburg/Borstel/Lübeck/Riems, Germany
| | - Kara Moser
- Institute for Genome Sciences, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
| | - Antoine Dara
- Institute for Genome Sciences, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
| | - Jan Strauss
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Meral Esen
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
- Cluster of Excellence: EXC 2124: Controlling Microbes to Fight Infection, Tübingen, Germany
| | - Rolf Fendel
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Zita Sulyok
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Myriam D Jeninga
- Institute of Microbiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Peter G Kremsner
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - B Kim Lee Sim
- Sanaria Inc., Rockville, Maryland, United States of America
| | | | - Michael F Duffy
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Thomas D Otto
- School of Infection & Immunity, University of Glasgow, Glasgow, United Kingdom
| | - Tim-Wolf Gilberger
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Lisboa, Portugal
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Michaela Petter
- Institute of Microbiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Anna Bachmann
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Hamburg/Borstel/Lübeck/Riems, Germany
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9
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Balbin JM, Heinemann GK, Yeoh LM, Gilberger TW, Armstrong M, Duffy MF, Gilson PR, Wilson DW. Characterisation of PfCZIF1 and PfCZIF2 in Plasmodium falciparum asexual stages. Int J Parasitol 2023; 53:27-41. [PMID: 36400305 DOI: 10.1016/j.ijpara.2022.09.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/30/2022] [Accepted: 09/25/2022] [Indexed: 11/17/2022]
Abstract
Plasmodium falciparum exerts strong temporal control of gene expression across its lifecycle. Proteins expressed exclusively during late schizogony of blood stages, for example, often have a role in facilitating merozoite invasion of the host red blood cell (RBC), through merozoite development, egress, invasion or early establishment of infection in the RBC. Here, we characterise P. falciparum C3H1 zinc finger 1 (PfCZIF1, Pf3D7_1468400) and P. falciparum C3H1 zinc finger 2 (PfCZIF2, Pf3D7_0818100) which we identified as the only C3H1-type zinc finger proteins with peak expression at schizogony. Previous studies reported that antibodies against PfCZIF1 inhibit merozoite invasion, suggesting this protein may have a potential role during RBC invasion. We show using C-terminal truncations and gene knockouts of each of Pfczif1 and Pfczif2 that neither are essential for blood stage growth. However, they could not both be knocked out simultaneously, suggesting that at least one is needed for parasite growth in vitro. Immunofluorescence localisation of PfCZIF1 and PfCZIF2 indicated that both proteins occur in discrete foci on the periphery of the parasite's cytosol and biochemical assays suggest they are peripherally associated to a membrane. Transcriptomic analyses for the C-terminal truncation mutants reveal no significant expression perturbations with PfCZIF1 truncation. However, modification of PfCZIF2 appears to modify the expression for some exported proteins including PfKAHRP. This study does not support a role for PfCZIF1 or PfCZIF2 in merozoite invasion of the RBC and suggests that these proteins may help regulate the expression of proteins exported into the RBC cytosol after merozoite invasion.
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Affiliation(s)
- Juan M Balbin
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide 5005, Australia. https://twitter.com/jmiguel_balbin
| | - Gary K Heinemann
- Experimental Therapeutics Laboratory, Clinical and Health Science Unit, University of South Australia, Adelaide, SA 5000, Australia
| | - Lee M Yeoh
- Burnet Institute, Melbourne 3004, Victoria, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne 3010, Victoria, Australia
| | - Tim-Wolf Gilberger
- Centre for Structural Systems Biology, 22607 Hamburg, Germany; Bernhard Nocht Institute for Tropical Medicine, 20359 Hamburg, Germany; University of Hamburg, 20146 Hamburg, Germany
| | | | - Michael F Duffy
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne 3010, Victoria, Australia
| | - Paul R Gilson
- Burnet Institute, Melbourne 3004, Victoria, Australia; Department of Microbiology and Immunology, The University of Melbourne, Melbourne 3010, Victoria, Australia
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide 5005, Australia; Burnet Institute, Melbourne 3004, Victoria, Australia; Institute for Photonics and Advanced Sensing (IPAS), University of Adelaide, 5005 SA, Australia.
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10
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Real E, Nardella F, Scherf A, Mancio-Silva L. Repurposing of Plasmodium falciparum var genes beyond the blood stage. Curr Opin Microbiol 2022; 70:102207. [PMID: 36183663 DOI: 10.1016/j.mib.2022.102207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/26/2022] [Accepted: 09/03/2022] [Indexed: 01/25/2023]
Abstract
A commonly observed survival strategy in protozoan parasites is the sequential expression of clonally variant-surface antigens to avoid elimination by the host's immune response. In malaria-causing P. falciparum, the immunovariant erythrocyte-membrane protein-1 (PfEMP1) adhesin family, encoded by var genes, is responsible for both antigenic variation and cytoadherence of infected erythrocytes to the microvasculature. Until recently, the biological function of these variant genes was believed to be restricted to intraerythrocytic developmental stages. With the advent of new technologies, var gene expression has been confirmed in transmission and pre-erythrocytic stages. Here, we discuss how repurposing of var gene expression beyond chronic blood-stage infection may be critical for successful transmission.
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Affiliation(s)
- Eliana Real
- Institut Pasteur, Université Paris Cité, Inserm U1201, CNRS EMR9195, Unité de Biologie des Interactions Hôte-Parasite, 25 Rue du Dr Roux, F-75015 Paris, France
| | - Flore Nardella
- Institut Pasteur, Université Paris Cité, Inserm U1201, CNRS EMR9195, Unité de Biologie des Interactions Hôte-Parasite, 25 Rue du Dr Roux, F-75015 Paris, France
| | - Artur Scherf
- Institut Pasteur, Université Paris Cité, Inserm U1201, CNRS EMR9195, Unité de Biologie des Interactions Hôte-Parasite, 25 Rue du Dr Roux, F-75015 Paris, France.
| | - Liliana Mancio-Silva
- Institut Pasteur, Université Paris Cité, Inserm U1201, CNRS EMR9195, Unité de Biologie des Interactions Hôte-Parasite, 25 Rue du Dr Roux, F-75015 Paris, France.
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11
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Hoshizaki J, Adjalley SH, Thathy V, Judge K, Berriman M, Reid AJ, Lee MCS. A manually curated annotation characterises genomic features of P. falciparum lncRNAs. BMC Genomics 2022; 23:780. [PMID: 36451097 PMCID: PMC9710153 DOI: 10.1186/s12864-022-09017-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 11/16/2022] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Important regulation occurs at the level of transcription in Plasmodium falciparum and growing evidence suggests that these apicomplexan parasites have complex regulatory networks. Recent studies implicate long noncoding RNAs (lncRNAs) as transcriptional regulators in P. falciparum. However, due to limited research and the lack of necessary experimental tools, our understanding of their role in the malaria-causing parasite remains largely unelucidated. In this work, we address one of these limitations, the lack of an updated and improved lncRNA annotation in P. falciparum. RESULTS We generated long-read RNA sequencing data and integrated information extracted and curated from multiple sources to manually annotate lncRNAs. We identified 1119 novel lncRNAs and validated and refined 1250 existing annotations. Utilising the collated datasets, we generated evidence-based ranking scores for each annotation and characterised the distinct genomic contexts and features of P. falciparum lncRNAs. Certain features indicated subsets with potential biological significance such as 25 lncRNAs containing multiple introns, 335 lncRNAs lacking mutations in piggyBac mutagenic studies and lncRNAs associated with specific biologic processes including two new types of lncRNAs found proximal to var genes. CONCLUSIONS The insights and the annotation presented in this study will serve as valuable tools for researchers seeking to understand the role of lncRNAs in parasite biology through both bioinformatics and experimental approaches.
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Affiliation(s)
- Johanna Hoshizaki
- grid.52788.300000 0004 0427 7672Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | - Sophie H. Adjalley
- grid.52788.300000 0004 0427 7672Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA UK ,Micrographia Bio, London, W12 0BZ UK
| | - Vandana Thathy
- grid.4991.50000 0004 1936 8948MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, OX3 9DS UK ,grid.239585.00000 0001 2285 2675Present address: Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY10032 USA
| | - Kim Judge
- grid.52788.300000 0004 0427 7672Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA UK
| | - Matthew Berriman
- grid.52788.300000 0004 0427 7672Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA UK ,grid.8756.c0000 0001 2193 314XWellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, G12 8TA UK
| | - Adam J. Reid
- grid.52788.300000 0004 0427 7672Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA UK ,grid.5335.00000000121885934Present address: Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, CB2 1QN UK
| | - Marcus C. S. Lee
- grid.52788.300000 0004 0427 7672Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA UK
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12
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Diffendall GM, Barcons-Simon A, Baumgarten S, Dingli F, Loew D, Scherf A. Discovery of RUF6 ncRNA-interacting proteins involved in P. falciparum immune evasion. Life Sci Alliance 2022; 6:6/1/e202201577. [PMID: 36379669 PMCID: PMC9670795 DOI: 10.26508/lsa.202201577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 10/25/2022] [Accepted: 10/26/2022] [Indexed: 11/16/2022] Open
Abstract
Non-coding RNAs (ncRNAs) are emerging regulators of immune evasion and transmission of Plasmodium falciparum RUF6 is an ncRNA gene family that is transcribed by RNA polymerase III but actively regulates the Pol II-transcribed var virulence gene family. Understanding how RUF6 ncRNA connects to downstream effectors is lacking. We developed an RNA-directed proteomic discovery (ChIRP-MS) protocol to identify in vivo RUF6 ncRNA-protein interactions. The RUF6 ncRNA interactome was purified with biotinylated antisense oligonucleotides. Quantitative label-free mass spectrometry identified several unique proteins linked to gene transcription including RNA Pol II subunits, nucleosome assembly proteins, and a homologue of DEAD box helicase 5 (DDX5). Affinity purification of Pf-DDX5 identified proteins originally found by our RUF6-ChIRP protocol, validating the technique's robustness for identifying ncRNA interactomes in P. falciparum Inducible displacement of nuclear Pf-DDX5 resulted in significant down-regulation of the active var gene. Our work identifies a RUF6 ncRNA-protein complex that interacts with RNA Pol II to sustain the var gene expression, including a helicase that may resolve G-quadruplex secondary structures in var genes to facilitate transcriptional activation and progression.
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Affiliation(s)
- Gretchen M Diffendall
- Universite Paris Cité, Institut Pasteur, Biology of Host-Parasite Interactions Unit, INSERM U1201, CNRS EMR9195, Paris, France,Sorbonne Université Ecole doctorale Complexité du Vivant ED515, Paris, France
| | - Anna Barcons-Simon
- Universite Paris Cité, Institut Pasteur, Biology of Host-Parasite Interactions Unit, INSERM U1201, CNRS EMR9195, Paris, France,Sorbonne Université Ecole doctorale Complexité du Vivant ED515, Paris, France,Biomedical Center, Division of Physiological Chemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | | | - Florent Dingli
- Institut Curie, PSL Research University, Centre de Recherche, CurieCoreTech Mass Spectrometry Proteomics, Paris, France
| | - Damarys Loew
- Institut Curie, PSL Research University, Centre de Recherche, CurieCoreTech Mass Spectrometry Proteomics, Paris, France
| | - Artur Scherf
- Universite Paris Cité, Institut Pasteur, Biology of Host-Parasite Interactions Unit, INSERM U1201, CNRS EMR9195, Paris, France
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13
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Abstract
In eukaryotic organisms, noncoding RNAs (ncRNAs) have been implicated as important regulators of multifaceted biological processes, including transcriptional, posttranscriptional, and epigenetic regulation of gene expression. In recent years, it is becoming clear that protozoan parasites encode diverse ncRNA transcripts; however, little is known about their cellular functions. Recent advances in high-throughput “omic” studies identified many novel long ncRNAs (lncRNAs) in apicomplexan parasites, some of which undergo splicing, polyadenylation, and encode small proteins. To date, only a few of them are characterized, leaving a big gap in our understanding regarding their origin, mode of action, and functions in parasite biology. In this review, we focus on lncRNAs of the human malaria parasite Plasmodium falciparum and highlight their cellular functions and possible mechanisms of action.
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Affiliation(s)
- Karina Simantov
- Department of Microbiology & Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Manish Goyal
- Department of Microbiology & Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Ron Dzikowski
- Department of Microbiology & Molecular Genetics, The Kuvin Center for the Study of Infectious and Tropical Diseases, IMRIC, The Hebrew University-Hadassah Medical School, Jerusalem, Israel
- * E-mail:
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14
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Sethumadhavan DV, Tiburcio M, Kanyal A, Jabeena CA, Govindaraju G, Karmodiya K, Rajavelu A. Chromodomain Protein Interacts with H3K9me3 and Controls RBC Rosette Formation by Regulating the Expression of a Subset of RIFINs in the Malaria Parasite. J Mol Biol 2022; 434:167601. [PMID: 35460670 DOI: 10.1016/j.jmb.2022.167601] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/04/2022] [Accepted: 04/17/2022] [Indexed: 11/27/2022]
Abstract
Plasmodium falciparum expresses clonally variant proteins on the surface of infected erythrocytes to evade the host immune system. The clonally variant multigene families include var, rifin, and stevor, which express Erythrocyte Membrane Protein 1 (EMP1), Repetitive Interspersed Families of polypeptides (RIFINs), and Sub-telomeric Variable Open Reading frame (STEVOR) proteins, respectively. The rifins are the largest multigene family and are essentially involved in the RBC rosetting, the hallmark of severe malaria. The molecular regulators that control the RIFINs expression in Plasmodium spp. have not been reported so far. This study reports a chromodomain-containing protein (PfCDP) that binds to H3K9me3 modification on P. falciparum chromatin. Conditional deletion of the chromodomain (CD) gene in P. falciparum using an inducible DiCre-LoxP system leads to selective up-regulation of a subset of virulence genes, including rifins, a few var, and stevor genes. Further, we show that PfCDP conditional knockout (PfΔCDP) promotes RBC rosette formation. This study provides the first evidence of an epigenetic regulator mediated control on a subset of RIFINs expression and RBC rosetting by P. falciparum.
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Affiliation(s)
- Devadathan Valiyamangalath Sethumadhavan
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology, Madras, Chennai, Tamil Nadu 600 036, India; Ph.D registered with Manipal Academy of Higher Education (MAHE), Tiger Circle Road, Madhav Nagar, Manipal, Karnataka 576 104, India
| | - Marta Tiburcio
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, United Kingdom
| | - Abhishek Kanyal
- Department of Biology, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411 008, Maharashtra, India. https://twitter.com/AbhishekKanyal7
| | - C A Jabeena
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology, Madras, Chennai, Tamil Nadu 600 036, India; Ph.D registered with Manipal Academy of Higher Education (MAHE), Tiger Circle Road, Madhav Nagar, Manipal, Karnataka 576 104, India
| | - Gayathri Govindaraju
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology, Madras, Chennai, Tamil Nadu 600 036, India; Ph.D registered with Manipal Academy of Higher Education (MAHE), Tiger Circle Road, Madhav Nagar, Manipal, Karnataka 576 104, India
| | - Krishanpal Karmodiya
- Department of Biology, Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411 008, Maharashtra, India. https://twitter.com/Krishanpal_K
| | - Arumugam Rajavelu
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology, Madras, Chennai, Tamil Nadu 600 036, India; Pathogen Biology, Rajiv Gandhi Centre for Biotechnology (RGCB), Thycaud PO, Thiruvananthapuram 695 014, Kerala, India.
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15
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Florini F, Visone JE, Deitsch KW. Shared Mechanisms for Mutually Exclusive Expression and Antigenic Variation by Protozoan Parasites. Front Cell Dev Biol 2022; 10:852239. [PMID: 35350381 PMCID: PMC8957917 DOI: 10.3389/fcell.2022.852239] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 02/17/2022] [Indexed: 01/05/2023] Open
Abstract
Cellular decision-making at the level of gene expression is a key process in the development and evolution of every organism. Variations in gene expression can lead to phenotypic diversity and the development of subpopulations with adaptive advantages. A prime example is the mutually exclusive activation of a single gene from within a multicopy gene family. In mammals, this ranges from the activation of one of the two immunoglobulin (Ig) alleles to the choice in olfactory sensory neurons of a single odorant receptor (OR) gene from a family of more than 1,000. Similarly, in parasites like Trypanosoma brucei, Giardia lamblia or Plasmodium falciparum, the process of antigenic variation required to escape recognition by the host immune system involves the monoallelic expression of vsg, vsp or var genes, respectively. Despite the importance of this process, understanding how this choice is made remains an enigma. The development of powerful techniques such as single cell RNA-seq and Hi-C has provided new insights into the mechanisms these different systems employ to achieve monoallelic gene expression. Studies utilizing these techniques have shown how the complex interplay between nuclear architecture, physical interactions between chromosomes and different chromatin states lead to single allele expression. Additionally, in several instances it has been observed that high-level expression of a single gene is preceded by a transient state where multiple genes are expressed at a low level. In this review, we will describe and compare the different strategies that organisms have evolved to choose one gene from within a large family and how parasites employ this strategy to ensure survival within their hosts.
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Affiliation(s)
| | | | - Kirk W. Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, United States
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16
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Shang X, Wang C, Fan Y, Guo G, Wang F, Zhao Y, Sheng F, Tang J, He X, Yu X, Zhang M, Zhu G, Yin S, Mu J, Culleton R, Cao J, Jiang M, Zhang Q. OUP accepted manuscript. Nucleic Acids Res 2022; 50:3413-3431. [PMID: 35288749 PMCID: PMC8989538 DOI: 10.1093/nar/gkac176] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/03/2022] [Accepted: 03/05/2022] [Indexed: 11/13/2022] Open
Abstract
Heterochromatin-associated gene silencing controls multiple physiological processes in malaria parasites, however, little is known concerning the regulatory network and cis-acting sequences involved in the organization of heterochromatin and how they modulate heterochromatic gene expression. Based on systematic profiling of genome-wide occupancy of eighteen Apicomplexan AP2 transcription factors by ChIP-seq analysis, we identify and characterize eight heterochromatin-associated factors (PfAP2-HFs), which exhibit preferential enrichment within heterochromatic regions but with differential coverage profiles. Although these ApiAP2s target euchromatic gene loci via specific DNA motifs, they are likely integral components of heterochromatin independent of DNA motif recognition. Systematic knockout screenings of ApiAP2 factors coupled with RNA-seq transcriptomic profiling revealed three activators and three repressors of heterochromatic gene expression including four PfAP2-HFs. Notably, expression of virulence genes is either completely silenced or significantly reduced upon the depletion of PfAP2-HC. Integrated multi-omics analyses reveal autoregulation and feed-forward loops to be common features of the ApiAP2 regulatory network, in addition to the occurrence of dynamic interplay between local chromatin structure and ApiAP2s in transcriptional control. Collectively, this study provides a valuable resource describing the genome-wide landscape of the ApiAP2 family and insights into functional divergence and cooperation within this family during the blood-stage development of malaria parasites.
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Affiliation(s)
| | | | | | | | - Fei Wang
- Laboratory of Molecular Parasitology, Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital; Clinical Center for Brain and Spinal Cord Research, School of Medicine, Tongji University, Shanghai 200092, China
| | - Yuemeng Zhao
- Laboratory of Molecular Parasitology, Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital; Clinical Center for Brain and Spinal Cord Research, School of Medicine, Tongji University, Shanghai 200092, China
| | - Fei Sheng
- Laboratory of Molecular Parasitology, Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital; Clinical Center for Brain and Spinal Cord Research, School of Medicine, Tongji University, Shanghai 200092, China
| | - Jianxia Tang
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, 214064, China
| | - Xiaoqin He
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, 214064, China
| | - Xinyu Yu
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, 214064, China
| | - Meihua Zhang
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, 214064, China
| | - Guoding Zhu
- National Health Commission Key Laboratory of Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi, 214064, China
| | - Shigang Yin
- Laboratory of Neurological Diseases and Brain Function, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Jianbing Mu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20892-8132, USA
| | - Richard Culleton
- Division of Molecular Parasitology, Proteo-Science Centre, Ehime University, Matsuyama, Ehime 790-8577, Japan
| | - Jun Cao
- Correspondence may also be addressed to Jun Cao. Tel: +05 10 6878 1007;
| | - Mei Jiang
- Correspondence may also be addressed to Mei Jiang. Tel: +86 21 6598 5138;
| | - Qingfeng Zhang
- To whom correspondence should be addressed. Tel: +86 21 6598 5138;
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17
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Zhang X, Deitsch KW, Dzikowski R. CRISPR-Cas9 Editing of the Plasmodium falciparum Genome: Special Applications. Methods Mol Biol 2022; 2470:241-253. [PMID: 35881350 DOI: 10.1007/978-1-0716-2189-9_18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The virulence of Plasmodium falciparum has been attributed in large part to the expression on the surface of infected red blood cells of the variant surface antigen Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1). Different forms of this protein are encoded by individual members of the multicopy gene family called var. Two attributes of the var gene family are key to the pathogenesis of malaria caused by P. falciparum; the hyperrecombinogenic nature of the var gene family that continuously generates antigenic diversity within parasite populations, and the ability of parasites to express only a single var gene at a time and to switch which gene is expressed over the course of an infection. The unique attributes of CRISPR-Cas9 have been applied to help decipher the molecular mechanisms underlying these unusual properties of the var gene family, both as a source of the DNA double strand breaks that initiate var gene recombination and as a way to recruit molecular probes to specific regions of the genome. In this chapter, we describe these somewhat unusual applications of the CRISPR-Cas9 system.
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Affiliation(s)
- Xu Zhang
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY, USA
| | - Kirk William Deitsch
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY, USA
| | - Ron Dzikowski
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research Israel-Canada, The Kuvin Center for the Study of Infectious and Tropical Diseases, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
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18
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Abstract
Malaria parasites need to cope with changing environmental conditions that require strong countermeasures to ensure pathogen survival in the human and mosquito hosts. The molecular mechanisms that protect Plasmodium falciparum homeostasis during the complex life cycle remain unknown. Here, we identify cytosine methylation of tRNAAsp (GTC) as being critical to maintain stable protein synthesis. Using conditional knockout (KO) of a member of the DNA methyltransferase family, called Pf-DNMT2, RNA bisulfite sequencing demonstrated the selective cytosine methylation of this enzyme of tRNAAsp (GTC) at position C38. Although no growth defect on parasite proliferation was observed, Pf-DNMT2KO parasites showed a selective downregulation of proteins with a GAC codon bias. This resulted in a significant shift in parasite metabolism, priming KO parasites for being more sensitive to various types of stress. Importantly, nutritional stress made tRNAAsp (GTC) sensitive to cleavage by an unknown nuclease and increased gametocyte production (>6-fold). Our study uncovers an epitranscriptomic mechanism that safeguards protein translation and homeostasis of sexual commitment in malaria parasites. IMPORTANCE P. falciparum is the most virulent malaria parasite species, accounting for the majority of the disease mortality and morbidity. Understanding how this pathogen is able to adapt to different cellular and environmental stressors during its complex life cycle is crucial in order to develop new strategies to tackle the disease. In this study, we identified the writer of a specific tRNA cytosine methylation site as a new layer of epitranscriptomic regulation in malaria parasites that regulates the translation of a subset of parasite proteins (>400) involved in different metabolic pathways. Our findings give insight into a novel molecular mechanism that regulates P. falciparum response to drug treatment and sexual commitment.
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19
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Markus BM, Boydston EA, Lourido S. CRISPR-Mediated Transcriptional Repression in Toxoplasma gondii. mSphere 2021; 6:e0047421. [PMID: 34643425 PMCID: PMC8513686 DOI: 10.1128/msphere.00474-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 09/23/2021] [Indexed: 11/20/2022] Open
Abstract
Tools for tuning endogenous gene expression are key to determining the genetic basis of diverse cellular phenotypes. Although synthetic regulatable promoters are available in Toxoplasma, scalable methods for targeted and combinatorial downregulation of gene expression-like RNA interference-have yet to be developed. To investigate the feasibility of CRISPR-mediated transcriptional regulation, we examined the function of two catalytically inactive Cas9 (dCas9) orthologs, from Streptococcus pyogenes and Streptococcus thermophilus, in Toxoplasma. Following the addition of single-guide RNAs (sgRNAs) targeting the promoter and 5' untranslated region (UTR) of the surface antigen gene SAG1, we profiled changes in protein abundance of targeted genes by flow cytometry for transcriptional reporters and immunoblotting. We found that the dCas9 orthologs generated a range of target gene expression levels, and the degree of repression was durable and stably inherited. Therefore, S. pyogenes and S. thermophilus dCas9 can effectively produce intermediate levels of gene expression in Toxoplasma. The distinct sgRNA scaffold requirements of the two dCas9s permit their orthogonal use for simultaneous examination of two distinct loci through transcriptional modulation, labeling for microscopy-based studies, or other dCas9-based approaches. Taking advantage of newly available genomic transcription start site data, these tools will aid in the development of new loss-of-function screening approaches in Toxoplasma. IMPORTANCE Toxoplasma gondii is a ubiquitous intracellular parasite of humans and animals that causes life-threatening disease in immunocompromised patients, fetal abnormalities when contracted during gestation, and recurrent eye lesions in some patients. Despite its health implications, about half of the Toxoplasma genome still lacks functional annotation. A particularly powerful tool for the investigation of an organism's cell biology is the modulation of gene expression, which can produce the subtle phenotypes often required for informing gene function. In Toxoplasma, such tools have limited throughput and versatility. Here, we detail the adaptation of a new set of tools based on CRISPR-Cas9, which allows the targeted downregulation of gene expression in Toxoplasma. With its scalability and adaptability to diverse genomic loci, this approach has the potential to greatly accelerate the functional characterization of the Toxoplasma genome.
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Affiliation(s)
- Benedikt M. Markus
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, USA
- Faculty of Biology, University of Freiburg, Freiburg, Germany
| | | | - Sebastian Lourido
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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20
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Briquet S, Gissot M, Silvie O. A toolbox for conditional control of gene expression in apicomplexan parasites. Mol Microbiol 2021; 117:618-631. [PMID: 34564906 PMCID: PMC9293482 DOI: 10.1111/mmi.14821] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 01/29/2023]
Abstract
Apicomplexan parasites encompass diverse pathogens for humans and animals, including the causative agents of malaria and toxoplasmosis, Plasmodium spp. and Toxoplasma gondii. Genetic manipulation of these parasites has become central to explore parasite biology, unravel gene function and identify new targets for therapeutic strategies. Tremendous progress has been achieved over the past years with the advent of next generation sequencing and powerful genome editing methods. In particular, various methods for conditional gene expression have been developed in both Plasmodium and Toxoplasma to knockout or knockdown essential genes, or for inducible expression of master developmental regulators or mutant versions of proteins. Conditional gene expression can be achieved at three distinct levels. At the DNA level, inducible site‐specific recombinases allow conditional genome editing. At the RNA level, regulation can be achieved during transcription, using stage‐specific or regulatable promoters, or post‐transcriptionally through alteration of mRNA stability or translation. At the protein level, several systems have been developed for inducible degradation or displacement of a protein of interest. In this review, we provide an overview of current systems for conditional control of gene expression in Plasmodium and Toxoplasma parasites, highlighting the advantages and limitations of each approach.
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Affiliation(s)
- Sylvie Briquet
- INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, Sorbonne Université, Paris, France
| | - Mathieu Gissot
- CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, Center for Infection and Immunity of Lille, CIIL, Univ. Lille, Lille, France
| | - Olivier Silvie
- INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, Sorbonne Université, Paris, France
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21
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The Architectural Factor HMGB1 Is Involved in Genome Organization in the Human Malaria Parasite Plasmodium falciparum. mBio 2021; 12:mBio.00148-21. [PMID: 33906919 PMCID: PMC8092211 DOI: 10.1128/mbio.00148-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The three-dimensional (3D) genome organization plays a critical role in the regulation of gene expression in eukaryotic organisms. In the unicellular malaria parasite Plasmodium falciparum, the high-order chromosome organization has emerged as an important epigenetic pathway mediating gene expression, particularly for virulence genes, but the related architectural factors and underlying mechanism remain elusive. Herein, we have identified the high-mobility-group protein HMGB1 as a critical architectural factor for maintenance of genome organization in P. falciparum Genome-wide occupancy analysis (chromatin immunoprecipitation sequencing [ChIP-seq]) shows that the HMGB1 protein is recruited mainly to centromeric regions likely via a DNA-binding-independent pathway. Chromosome conformation capture coupled with next-generation sequencing (Hi-C-seq) and 3D modeling analysis show that the loss of HMGB1 disrupts the integrity of centromere/telomere-based chromosome organization accompanied with diminished interaction frequency among centromere clusters. This triggers local chromatin alteration and dysregulated gene expression. Notably, the entire repertoire of the primary virulence genes (var) was completely silenced in the absence of P. falciparum HMGB1 (PfHMGB1). Furthermore, the disrupted nuclear organization was reconstituted by complementation of HMGB1, thereby rescuing the mutually exclusive expression of the var gene family. Collectively, these data demonstrate that the architectural factor HMGB1 is associated with gene expression via mediating the high-order structure of genome organization. This finding not only contributes better understanding of the epigenetic regulation of gene expression but may also provide novel targets for antimalarial strategies.IMPORTANCE Malaria remains a major public health and economic burden currently. The mutually exclusive expression of the virulence genes is associated with the pathogenesis and immune evasion of human malaria parasites in the host. The nuclear architecture provides a well-organized environment for differential gene expression in the nucleus, but the underlying mechanism remains largely unknown. In this study, we have identified the highly conserved high-mobility-group protein HMGB1 as a key architecture regulator involved in virulence gene expression by establishing high-order genome organization in the nucleus of P. falciparum Mechanistic investigation revealed that the specific interaction of HMGB1 and centromeres constructed the precisely organized nuclear architecture, which coordinated with local chromatin structure to control the singular expression of virulence genes. Hence, this protein appears to be a critical architectural regulator for the pathogenesis of malaria infection and may be a new target for the development of an intervention strategy against malaria.
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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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Li Y, Baptista RP, Sateriale A, Striepen B, Kissinger JC. Analysis of Long Non-Coding RNA in Cryptosporidium parvum Reveals Significant Stage-Specific Antisense Transcription. Front Cell Infect Microbiol 2021; 10:608298. [PMID: 33520737 PMCID: PMC7840661 DOI: 10.3389/fcimb.2020.608298] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 11/26/2020] [Indexed: 12/13/2022] Open
Abstract
Cryptosporidium is a protist parasite that has been identified as the second leading cause of moderate to severe diarrhea in children younger than two and a significant cause of mortality worldwide. Cryptosporidium has a complex, obligate, intracellular but extra cytoplasmic lifecycle in a single host. How genes are regulated in this parasite remains largely unknown. Long non-coding RNAs (lncRNAs) play critical regulatory roles, including gene expression across a broad range of organisms. Cryptosporidium lncRNAs have been reported to enter the host cell nucleus and affect the host response. However, no systematic study of lncRNAs in Cryptosporidium has been conducted to identify additional lncRNAs. In this study, we analyzed a C. parvum in vitro strand-specific RNA-seq developmental time series covering both asexual and sexual stages to identify lncRNAs associated with parasite development. In total, we identified 396 novel lncRNAs, mostly antisense, with 86% being differentially expressed. Surprisingly, nearly 10% of annotated mRNAs have an antisense transcript. lncRNAs occur most often at the 3' end of their corresponding sense mRNA. Putative lncRNA regulatory regions were identified and many appear to encode bidirectional promoters. A positive correlation between lncRNA and upstream mRNA expression was observed. Evolutionary conservation and expression of lncRNA candidates was observed between C. parvum, C. hominis and C. baileyi. Ten C. parvum protein-encoding genes with antisense transcripts have P. falciparum orthologs that also have antisense transcripts. Three C. parvum lncRNAs with exceptional properties (e.g., intron splicing) were experimentally validated using RT-PCR and RT-qPCR. This initial characterization of the C. parvum non-coding transcriptome facilitates further investigations into the roles of lncRNAs in parasite development and host-pathogen interactions.
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Affiliation(s)
- Yiran Li
- Institute of Bioinformatics, University of Georgia, Athens, GA, United States
| | - Rodrigo P. Baptista
- Institute of Bioinformatics, University of Georgia, Athens, GA, United States
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Adam Sateriale
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Boris Striepen
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Jessica C. Kissinger
- Institute of Bioinformatics, University of Georgia, Athens, GA, United States
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
- Department of Genetics, University of Georgia, Athens, GA, United States
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Hollin T, Le Roch KG. From Genes to Transcripts, a Tightly Regulated Journey in Plasmodium. Front Cell Infect Microbiol 2020; 10:618454. [PMID: 33425787 PMCID: PMC7793691 DOI: 10.3389/fcimb.2020.618454] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 11/19/2020] [Indexed: 12/17/2022] Open
Abstract
Over the past decade, we have witnessed significant progresses in understanding gene regulation in Apicomplexa including the human malaria parasite, Plasmodium falciparum. This parasite possesses the ability to convert in multiple stages in various hosts, cell types, and environments. Recent findings indicate that P. falciparum is talented at using efficient and complementary molecular mechanisms to ensure a tight control of gene expression at each stage of its life cycle. Here, we review the current understanding on the contribution of the epigenome, atypical transcription factors, and chromatin organization to regulate stage conversion in P. falciparum. The adjustment of these regulatory mechanisms occurring during the progression of the life cycle will be extensively discussed.
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Affiliation(s)
- Thomas Hollin
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, United States
| | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, United States
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Li Y, Baptista RP, Kissinger JC. Noncoding RNAs in Apicomplexan Parasites: An Update. Trends Parasitol 2020; 36:835-849. [DOI: 10.1016/j.pt.2020.07.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 06/26/2020] [Accepted: 07/18/2020] [Indexed: 12/16/2022]
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26
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Dynamic Chromatin Structure and Epigenetics Control the Fate of Malaria Parasites. Trends Genet 2020; 37:73-85. [PMID: 32988634 DOI: 10.1016/j.tig.2020.09.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/27/2020] [Accepted: 09/02/2020] [Indexed: 12/11/2022]
Abstract
Multiple hosts and various life cycle stages prompt the human malaria parasite, Plasmodium falciparum, to acquire sophisticated molecular mechanisms to ensure its survival, spread, and transmission to its next host. To face these environmental challenges, increasing evidence suggests that the parasite has developed complex and complementary layers of regulatory mechanisms controlling gene expression. Here, we discuss the recent developments in the discovery of molecular components that contribute to cell replication and differentiation and highlight the major contributions of epigenetics, transcription factors, and nuclear architecture in controlling gene regulation and life cycle progression in Plasmodium spp.
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27
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Defining multiplicity of vector uptake in transfected Plasmodium parasites. Sci Rep 2020; 10:10894. [PMID: 32616799 PMCID: PMC7331667 DOI: 10.1038/s41598-020-67791-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 06/15/2020] [Indexed: 11/08/2022] Open
Abstract
The recurrent emergence of drug resistance in Plasmodium falciparum increases the urgency to genetically validate drug resistance mechanisms and identify new targets. Reverse genetics have facilitated genome-scale knockout screens in Plasmodium berghei and Toxoplasma gondii, in which pooled transfections of multiple vectors were critical to increasing scale and throughput. These approaches have not yet been implemented in human malaria species such as P. falciparum and P. knowlesi, in part because the extent to which pooled transfections can be performed in these species remains to be evaluated. Here we use next-generation sequencing to quantitate uptake of a pool of 94 barcoded vectors. The distribution of vector acquisition allowed us to estimate the number of barcodes and DNA molecules taken up by the parasite population. Dilution cloning of P. falciparum transfectants showed that individual clones possess as many as seven episomal barcodes, revealing that an intake of multiple vectors is a frequent event despite the inefficient transfection efficiency. Transfection of three spectrally-distinct fluorescent reporters allowed us to evaluate different transfection methods and revealed that schizont-stage transfection limited the tendency for parasites to take up multiple vectors. In contrast to P. falciparum, we observed that the higher transfection efficiency of P. knowlesi resulted in near complete representation of the library. These findings have important implications for how reverse genetics can be scaled in culturable Plasmodium species.
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28
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Abstract
Malaria remains a major public health and economic burden. The heterochromatin environment controls the silencing of genes associated with the fate of malaria parasites. Previous studies have demonstrated that a group of GC-rich ncRNAs (RUF6) is associated with the mutually exclusive expression of var genes, but the underlying mechanisms remain elusive. Here, through a series of genetic manipulation and genome-wide multiomics analysis, we have identified the plasmodial orthologue of RNA exosome-associated Rrp6 as an upstream regulator of RUF6 expression and revealed that the dysregulation of RUF6 upon Rrp6 knockdown triggered local chromatin alteration, thereby activating most heterochromatic genes via direct interaction of RUF6 and distal gene loci. This finding not only uncovered the in-depth mechanism of RUF6-mediated regulation of heterochromatic genes but also identified Rrp6 as a novel regulator of gene expression in human malaria parasites, which provides a new target for developing intervention strategies against malaria. The heterochromatin environment plays a central role in silencing genes associated with the malaria parasite’s development, survival in the host, and transmission to the mosquito vector. However, the underlying mechanism regulating the dynamic chromatin structure is not understood yet. Here, we have uncovered that Plasmodium falciparum Rrp6, an orthologue of eukaryotic RNA exosome-associated RNase, controls the silencing of heterochromatic genes. PfRrp6 knockdown disrupted the singular expression of the GC-rich ncRNA RUF6 family, a known critical regulator of virulence gene expression, through the stabilization of the nascent transcripts. Mechanistic investigation showed that the accumulation of the multiple RUF6 ncRNAs triggered local chromatin remodeling in situ, which activated their adjacent var genes. Strikingly, chromatin isolation by RNA purification analysis (ChIRP-seq) revealed that a remarkable RUF6 ncRNA had interacted with distal heterochromatin regions directly and stimulated a global derepression effect on heterochromatic genes, including all variant gene families and the sexual commitment-associated regulator ap2-g gene. Collectively, Rrp6 appears to conduct the epigenetic surveillance of heterochromatic gene expression through controlling RUF6 levels, thereby securing antigenic variation and sexual commitment of malaria parasites during the infection of the host.
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