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Lee BST, Sinha A, Dedon P, Preiser P. Charting new territory: The Plasmodium falciparum tRNA modification landscape. Biomed J 2024:100745. [PMID: 38734409 DOI: 10.1016/j.bj.2024.100745] [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: 03/26/2024] [Revised: 05/02/2024] [Accepted: 05/05/2024] [Indexed: 05/13/2024] Open
Abstract
Ribonucleoside modifications comprising the epitranscriptome are present in all organisms and all forms of RNA, including mRNA, rRNA and tRNA, the three major RNA components of the translational machinery. Of these, tRNA is the most heavily modified and the tRNA epitranscriptome has the greatest diversity of modifications. In addition to their roles in tRNA biogenesis, quality control, structure, cleavage, and codon recognition, tRNA modifications have been shown to regulate gene expression post-transcriptionally in prokaryotes and eukaryotes, including humans. However, studies investigating the impact of tRNA modifications on gene expression in the malaria parasite Plasmodium falciparum are currently scarce. Current evidence shows that the parasite has a limited capacity for transcriptional control, which points to a heavier reliance on strategies for posttranscriptional regulation such as tRNA epitranscriptome reprogramming. This review addresses the known functions of tRNA modifications in the biology of P. falciparum while highlighting the potential therapeutic opportunities and the value of using P. falciparum as a model organism for addressing several open questions related to the tRNA epitranscriptome.
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Affiliation(s)
- Benjamin Sian Teck Lee
- Antimicrobial Resistance IRG, Singapore MIT Alliance for Research and Technology, Singapore
| | - Ameya Sinha
- Antimicrobial Resistance IRG, Singapore MIT Alliance for Research and Technology, Singapore;; School of Biological Sciences, Nanyang Technological University, Singapore
| | - Peter Dedon
- Antimicrobial Resistance IRG, Singapore MIT Alliance for Research and Technology, Singapore;; Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA USA.
| | - Peter Preiser
- Antimicrobial Resistance IRG, Singapore MIT Alliance for Research and Technology, Singapore;; School of Biological Sciences, Nanyang Technological University, Singapore;.
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2
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Werner A, Kanhere A, Wahlestedt C, Mattick JS. Natural antisense transcripts as versatile regulators of gene expression. Nat Rev Genet 2024:10.1038/s41576-024-00723-z. [PMID: 38632496 DOI: 10.1038/s41576-024-00723-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2024] [Indexed: 04/19/2024]
Abstract
Long non-coding RNAs (lncRNAs) are emerging as a major class of gene products that have central roles in cell and developmental biology. Natural antisense transcripts (NATs) are an important subset of lncRNAs that are expressed from the opposite strand of protein-coding and non-coding genes and are a genome-wide phenomenon in both eukaryotes and prokaryotes. In eukaryotes, a myriad of NATs participate in regulatory pathways that affect expression of their cognate sense genes. Recent developments in the study of NATs and lncRNAs and large-scale sequencing and bioinformatics projects suggest that whether NATs regulate expression, splicing, stability or translation of the sense transcript is influenced by the pattern and degrees of overlap between the sense-antisense pair. Moreover, epigenetic gene regulatory mechanisms prevail in somatic cells whereas mechanisms dependent on the formation of double-stranded RNA intermediates are prevalent in germ cells. The modulating effects of NATs on sense transcript expression make NATs rational targets for therapeutic interventions.
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Affiliation(s)
| | | | | | - John S Mattick
- University of New South Wales, Sydney, New South Wales, Australia
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3
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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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4
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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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5
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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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6
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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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7
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Alvarez DR, Ospina A, Barwell T, Zheng B, Dey A, Li C, Basu S, Shi X, Kadri S, Chakrabarti K. The RNA structurome in the asexual blood stages of malaria pathogen plasmodium falciparum. RNA Biol 2021; 18:2480-2497. [PMID: 33960872 DOI: 10.1080/15476286.2021.1926747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Plasmodium falciparum is a deadly human pathogen responsible for the devastating disease called malaria. In this study, we measured the differential accumulation of RNA secondary structures in coding and non-coding transcripts from the asexual developmental cycle in P. falciparum in human red blood cells. Our comprehensive analysis that combined high-throughput nuclease mapping of RNA structures by duplex RNA-seq, SHAPE-directed RNA structure validation, immunoaffinity purification and characterization of antisense RNAs collectively measured differentially base-paired RNA regions throughout the parasite's asexual RBC cycle. Our mapping data not only aligned to a diverse pool of RNAs with known structures but also enabled us to identify new structural RNA regions in the malaria genome. On average, approximately 71% of the genes with secondary structures are found to be protein coding mRNAs. The mapping pattern of these base-paired RNAs corresponded to all regions of mRNAs, including the 5' UTR, CDS and 3' UTR as well as the start and stop codons. Histone family genes which are known to form secondary structures in their mRNAs and transcripts from genes which are important for transcriptional and post-transcriptional control, such as the unique plant-like transcription factor family, ApiAP2, DNA-/RNA-binding protein, Alba3 and proteins important for RBC invasion and malaria cytoadherence also showed strong accumulation of duplex RNA reads in various asexual stages in P. falciparum. Intriguingly, our study determined stage-specific, dynamic relationships between mRNA structural contents and translation efficiency in P. falciparum asexual blood stages, suggesting an essential role of RNA structural changes in malaria gene expression programs.
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Affiliation(s)
- Diana Renteria Alvarez
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
| | - Alejandra Ospina
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
| | - Tiffany Barwell
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
| | - Bo Zheng
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
| | - Abhishek Dey
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
| | - Chong Li
- Temple University, Philadelphia, PA, USA
| | - Shrabani Basu
- Division of Medical Genetics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA
| | | | - Sabah Kadri
- Division of Health and Biomedical Informatics, Northwestern University Feinberg School of Medicine and Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Kausik Chakrabarti
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina, USA
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8
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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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9
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Bennink S, Pradel G. The molecular machinery of translational control in malaria parasites. Mol Microbiol 2019; 112:1658-1673. [PMID: 31531994 DOI: 10.1111/mmi.14388] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2019] [Indexed: 12/30/2022]
Abstract
Translational control regulates the levels of protein synthesized from its transcript and is key for the rapid adjustment of gene expression in response to environmental stimuli. The regulation of translation is of special importance for malaria parasites, which pass through a complex life cycle that includes various replication phases in the different organs of the human and mosquito hosts and a sexual reproduction phase in the mosquito midgut. In particular, the quiescent transmission stages rely on translational control to rapidly adapt to the new environment, once they switch over from the human to the mosquito and vice versa. Three control mechanisms are currently proposed in Plasmodium, (1) global regulation that acts on the translation initiation complex; (2) mRNA-specific regulation, involving cis control elements, mRNA-binding proteins and translational repressors; and (3) induced mRNA decay by the Ccr4-Not and the RNA exosome complex. The main molecules controlling translation are highly conserved in malaria parasites and an increasing number of studies shed light on the interwoven pathways leading to the up or downregulation of protein synthesis in the diverse plasmodial stages. We here highlight recent findings on translational control during life cycle progression of Plasmodium and discuss the molecules involved in regulating protein synthesis.
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Affiliation(s)
- Sandra Bennink
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany
| | - Gabriele Pradel
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Worringerweg 1, 52074, Aachen, Germany
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10
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Ng CS, Sinha A, Aniweh Y, Nah Q, Babu IR, Gu C, Chionh YH, Dedon PC, Preiser PR. tRNA epitranscriptomics and biased codon are linked to proteome expression in Plasmodium falciparum. Mol Syst Biol 2018; 14:e8009. [PMID: 30287681 PMCID: PMC6171970 DOI: 10.15252/msb.20178009] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 08/09/2018] [Accepted: 09/07/2018] [Indexed: 12/24/2022] Open
Abstract
Among components of the translational machinery, ribonucleoside modifications on tRNAs are emerging as critical regulators of cell physiology and stress response. Here, we demonstrate highly coordinated behavior of the repertoire of tRNA modifications of Plasmodium falciparum throughout the intra-erythrocytic developmental cycle (IDC). We observed both a synchronized increase in 22 of 28 modifications from ring to trophozoite stage, consistent with tRNA maturation during translational up-regulation, and asynchronous changes in six modifications. Quantitative analysis of ~2,100 proteins across the IDC revealed that up- and down-regulated proteins in late but not early stages have a marked codon bias that directly correlates with parallel changes in tRNA modifications and enhanced translational efficiency. We thus propose a model in which tRNA modifications modulate the abundance of stage-specific proteins by enhancing translation efficiency of codon-biased transcripts for critical genes. These findings reveal novel epitranscriptomic and translational control mechanisms in the development and pathogenesis of Plasmodium parasites.
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Affiliation(s)
- Chee Sheng Ng
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore City, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ameya Sinha
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore City, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yaw Aniweh
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
| | - Qianhui Nah
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore City, Singapore
| | - Indrakanti Ramesh Babu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Chen Gu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yok Hian Chionh
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore City, Singapore
- Department of Microbiology and Immunology Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore City, Singapore
| | - Peter C Dedon
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore City, Singapore
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Peter R Preiser
- Antimicrobial Resistance Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore City, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore City, Singapore
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11
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Crater AK, Roscoe S, Fahim A, Ananvoranich S. Toxoplasma ubiquitin-like protease 1, a key enzyme in sumoylation and desumoylation pathways, is under the control of non-coding RNAs. Int J Parasitol 2018; 48:867-880. [PMID: 30005881 DOI: 10.1016/j.ijpara.2018.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 05/15/2018] [Accepted: 05/17/2018] [Indexed: 11/17/2022]
Abstract
Sumoylation and desumoylation are reversible pathways responsible for modification of protein structures and functions by the reversible covalent attachment of a small ubiquitin-like modifier (SUMO) peptide. These pathways are important for a wide range of cellular processes and require a steady supply of SUMO, which is generated by an enzymatic reaction catalysed by the ubiquitin-like protease (Ulp) family. Here we show by functional complementation analysis that the Ulp1 of Toxoplasma gondii (TgUlp1) can rescue a growth-deficient phenotype of a yeast-Ulp1 knockout. Recombinant TgUlp1 is an active enzyme capable of removing SUMO from a sumoylated substrate. Using a clonal transgenic strain of T. gondii expressing an epitope-tagged version of TgUlp1, we detected that the expression of TgUlp1 is modulated by Tg-miR-60, the most abundant species of micro RNA found in the T. gondii type 1 strain. The introduction of Tg-miR-60 inhibitor caused an increase in TgUlp1 expression and its enzymatic activity, as well as affecting the parasite's growth fitness. Moreover, we discovered a polyadenylated antisense RNA transcribed from the TgUlp1 locus, referred to as TgUlp1-NAT1 (TgUlp1-natural antisense transcript 1). Both Tg-miR-60 and TgUlp1-NAT1 confer a regulatory function by down-regulating the expression of TgUlp1 and affecting the sumoylation and desumoylation pathways in T. gondii.
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Affiliation(s)
- Anna K Crater
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B3P4, Canada
| | - Scott Roscoe
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B3P4, Canada
| | - Ambreen Fahim
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B3P4, Canada
| | - Sirinart Ananvoranich
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario N9B3P4, Canada.
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12
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Roy S, Jagus R, Morse D. Translation and Translational Control in Dinoflagellates. Microorganisms 2018; 6:microorganisms6020030. [PMID: 29642465 PMCID: PMC6027434 DOI: 10.3390/microorganisms6020030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 12/24/2022] Open
Abstract
Dinoflagellates are unicellular protists that feature a multitude of unusual nuclear features, including large genomes, packaging of DNA without histones, and multiple gene copies organized as tandem gene arrays. Furthermore, all dinoflagellate mRNAs experience trans-splicing with a common 22-nucleotide splice leader (SL) sequence. These features challenge some of the concepts and assumptions about the regulation of gene expression derived from work on model eukaryotes such as yeasts and mammals. Translational control in the dinoflagellates, based on extensive study of circadian bioluminescence and by more recent microarray and transcriptome analyses, is now understood to be a crucial element in regulating gene expression. A picture of the translation machinery of dinoflagellates is emerging from the recent availability of transcriptomes of multiple dinoflagellate species and the first complete genome sequences. The components comprising the translational control toolkit of dinoflagellates are beginning to take shape and are outlined here.
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Affiliation(s)
- Sougata Roy
- Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Sherbrooke East, Montréal, QC H1X 2B2, Canada.
| | - Rosemary Jagus
- Institute of Marine & Environmental Technology, University of Maryland Center for Environmental Science701 E. Pratt St., Baltimore, MD 21202, USA.
| | - David Morse
- Institut de Recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Sherbrooke East, Montréal, QC H1X 2B2, Canada.
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13
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Vembar SS, Droll D, Scherf A. Translational regulation in blood stages of the malaria parasite Plasmodium spp.: systems-wide studies pave the way. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:772-792. [PMID: 27230797 PMCID: PMC5111744 DOI: 10.1002/wrna.1365] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/21/2016] [Accepted: 04/26/2016] [Indexed: 11/10/2022]
Abstract
The malaria parasite Plasmodium spp. varies the expression profile of its genes depending on the host it resides in and its developmental stage. Virtually all messenger RNA (mRNA) is expressed in a monocistronic manner, with transcriptional activation regulated at the epigenetic level and by specialized transcription factors. Furthermore, recent systems-wide studies have identified distinct mechanisms of post-transcriptional and translational control at various points of the parasite lifecycle. Taken together, it is evident that 'just-in-time' transcription and translation strategies coexist and coordinate protein expression during Plasmodium development, some of which we review here. In particular, we discuss global and specific mechanisms that control protein translation in blood stages of the human malaria parasite Plasmodium falciparum, once a cytoplasmic mRNA has been generated, and its crosstalk with mRNA decay and storage. We also focus on the widespread translational delay observed during the 48-hour blood stage lifecycle of P. falciparum-for over 30% of transcribed genes, including virulence factors required to invade erythrocytes-and its regulation by cis-elements in the mRNA, RNA-processing enzymes and RNA-binding proteins; the first-characterized amongst these are the DNA- and RNA-binding Alba proteins. More generally, we conclude that translational regulation is an emerging research field in malaria parasites and propose that its elucidation will not only shed light on the complex developmental program of this parasite, but may also reveal mechanisms contributing to drug resistance and define new targets for malaria intervention strategies. WIREs RNA 2016, 7:772-792. doi: 10.1002/wrna.1365 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Shruthi Sridhar Vembar
- Unité Biologie des Interactions Hôte-Parasite, Département de Parasites et Insectes Vecteurs, Institut Pasteur, Paris, France.
| | - Dorothea Droll
- Unité Biologie des Interactions Hôte-Parasite, Département de Parasites et Insectes Vecteurs, Institut Pasteur, Paris, France
| | - Artur Scherf
- Unité Biologie des Interactions Hôte-Parasite, Département de Parasites et Insectes Vecteurs, Institut Pasteur, Paris, France
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Inhibition of Plasmodium falciparum proliferation in vitro by double-stranded RNA nanoparticle against malaria topoisomerase II. Exp Parasitol 2016; 164:84-90. [DOI: 10.1016/j.exppara.2016.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 03/02/2016] [Accepted: 03/04/2016] [Indexed: 11/21/2022]
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15
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Plasmodium falciparum PfSET7: enzymatic characterization and cellular localization of a novel protein methyltransferase in sporozoite, liver and erythrocytic stage parasites. Sci Rep 2016; 6:21802. [PMID: 26902486 PMCID: PMC4763181 DOI: 10.1038/srep21802] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/01/2016] [Indexed: 02/07/2023] Open
Abstract
Epigenetic control via reversible histone methylation regulates transcriptional activation throughout the malaria parasite genome, controls the repression of multi-copy virulence gene families and determines sexual stage commitment. Plasmodium falciparum encodes ten predicted SET domain-containing protein methyltransferases, six of which have been shown to be refractory to knock-out in blood stage parasites. We have expressed and purified the first recombinant malaria methyltransferase in sufficient quantities to perform a full enzymatic characterization and reveal the ill-defined PfSET7 is an AdoMet-dependent histone H3 lysine methyltransferase with highest activity towards lysines 4 and 9. Steady-state kinetics of the PfSET7 enzyme are similar to previously characterized histone methyltransferase enzymes from other organisms, however, PfSET7 displays specific protein substrate preference towards nucleosomes with pre-existing histone H3 lysine 14 acetylation. Interestingly, PfSET7 localizes to distinct cytoplasmic foci adjacent to the nucleus in erythrocytic and liver stage parasites, and throughout the cytoplasm in salivary gland sporozoites. Characterized recombinant PfSET7 now allows for target based inhibitor discovery. Specific PfSET7 inhibitors can aid in further investigating the biological role of this specific methyltransferase in transmission, hepatic and blood stage parasites, and may ultimately lead to the development of suitable antimalarial drug candidates against this novel class of essential parasite enzymes.
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Ramaprasad A, Mourier T, Naeem R, Malas TB, Moussa E, Panigrahi A, Vermont SJ, Otto TD, Wastling J, Pain A. Comprehensive evaluation of Toxoplasma gondii VEG and Neospora caninum LIV genomes with tachyzoite stage transcriptome and proteome defines novel transcript features. PLoS One 2015; 10:e0124473. [PMID: 25875305 PMCID: PMC4395442 DOI: 10.1371/journal.pone.0124473] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Accepted: 03/02/2015] [Indexed: 11/25/2022] Open
Abstract
Toxoplasma gondii is an important protozoan parasite that infects all warm-blooded animals and causes opportunistic infections in immuno-compromised humans. Its closest relative, Neospora caninum, is an important veterinary pathogen that causes spontaneous abortion in livestock. Comparative genomics of these two closely related coccidians has been of particular interest to identify genes that contribute to varied host cell specificity and disease. Here, we describe a manual evaluation of these genomes based on strand-specific RNA sequencing and shotgun proteomics from the invasive tachyzoite stages of these two parasites. We have corrected predicted structures of over one third of the previously annotated gene models and have annotated untranslated regions (UTRs) in over half of the predicted protein-coding genes. We observe distinctly long UTRs in both the organisms, almost four times longer than other model eukaryotes. We have also identified a putative set of cis-natural antisense transcripts (cis-NATs) and long intergenic non-coding RNAs (lincRNAs). We have significantly improved the annotation quality in these genomes that would serve as a manually curated dataset for Toxoplasma and Neospora research communities.
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Affiliation(s)
- Abhinay Ramaprasad
- Pathogen Genomics Laboratory, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Jeddah, Kingdom of Saudi Arabia
| | - Tobias Mourier
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - Raeece Naeem
- Pathogen Genomics Laboratory, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Jeddah, Kingdom of Saudi Arabia
| | - Tareq B. Malas
- Pathogen Genomics Laboratory, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Jeddah, Kingdom of Saudi Arabia
| | - Ehab Moussa
- Pathogen Genomics Laboratory, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Jeddah, Kingdom of Saudi Arabia
| | - Aswini Panigrahi
- Bioscience Core Laboratory (BCL), King Abdullah University of Science and Technology (KAUST), Thuwal, Jeddah, Kingdom of Saudi Arabia
| | - Sarah J. Vermont
- Institute of Infection and Global Health and School of Veterinary Science, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, Merseyside, United Kingdom
| | - Thomas D. Otto
- Parasite Genomics Group, Wellcome Trust Sanger Institute (WTSI), Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Jonathan Wastling
- Institute of Infection and Global Health and School of Veterinary Science, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, Merseyside, United Kingdom
| | - Arnab Pain
- Pathogen Genomics Laboratory, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Jeddah, Kingdom of Saudi Arabia
- * E-mail:
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Antisense long noncoding RNAs regulate var gene activation in the malaria parasite Plasmodium falciparum. Proc Natl Acad Sci U S A 2015; 112:E982-91. [PMID: 25691743 DOI: 10.1073/pnas.1420855112] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The virulence of Plasmodium falciparum, the causative agent of the deadliest form of human malaria, is attributed to its ability to evade human immunity through antigenic variation. These parasites alternate between expression of variable antigens, encoded by members of a multicopy gene family named var. Immune evasion through antigenic variation depends on tight regulation of var gene expression, ensuring that only a single var gene is expressed at a time while the rest of the family is maintained transcriptionally silent. Understanding how a single gene is chosen for activation is critical for understanding mutually exclusive expression but remains a mystery. Here, we show that antisense long noncoding RNAs (lncRNAs) initiating from var introns are associated with the single active var gene at the time in the cell cycle when the single var upstream promoter is active. We demonstrate that these antisense transcripts are incorporated into chromatin, and that expression of these antisense lncRNAs in trans triggers activation of a silent var gene in a sequence- and dose-dependent manner. On the other hand, interference with these lncRNAs using complement peptide nucleic acid molecules down-regulated the active var gene, erased the epigenetic memory, and induced expression switching. Altogether, our data provide evidence that these antisense lncRNAs play a key role in regulating var gene activation and mutually exclusive expression.
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Proietti C, Doolan DL. The case for a rational genome-based vaccine against malaria. Front Microbiol 2015; 5:741. [PMID: 25657640 PMCID: PMC4302942 DOI: 10.3389/fmicb.2014.00741] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 12/06/2014] [Indexed: 12/22/2022] Open
Abstract
Historically, vaccines have been designed to mimic the immunity induced by natural exposure to the target pathogen, but this approach has not been effective for any parasitic pathogen of humans or complex pathogens that cause chronic disease in humans, such as Plasmodium. Despite intense efforts by many laboratories around the world on different aspects of Plasmodium spp. molecular and cell biology, epidemiology and immunology, progress towards the goal of an effective malaria vaccine has been disappointing. The premise of rational vaccine design is to induce the desired immune response against the key pathogen antigens or epitopes targeted by protective immune responses. We advocate that development of an optimally efficacious malaria vaccine will need to improve on nature, and that this can be accomplished by rational vaccine design facilitated by mining genomic, proteomic and transcriptomic datasets in the context of relevant biological function. In our opinion, modern genome-based rational vaccine design offers enormous potential above and beyond that of whole-organism vaccines approaches established over 200 years ago where immunity is likely suboptimal due to the many genetic and immunological host-parasite adaptations evolved to allow the Plasmodium parasite to coexist in the human host, and which are associated with logistic and regulatory hurdles for production and delivery.
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Affiliation(s)
- Carla Proietti
- Infectious Diseases Program, QIMR Berghofer Medical Research Institute Brisbane, QLD, Australia
| | - Denise L Doolan
- Infectious Diseases Program, QIMR Berghofer Medical Research Institute Brisbane, QLD, Australia
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Caro F, Ahyong V, Betegon M, DeRisi JL. Genome-wide regulatory dynamics of translation in the Plasmodium falciparum asexual blood stages. eLife 2014; 3. [PMID: 25493618 PMCID: PMC4371882 DOI: 10.7554/elife.04106] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 11/06/2014] [Indexed: 12/11/2022] Open
Abstract
The characterization of the transcriptome and proteome of Plasmodium
falciparum has been a tremendous resource for the understanding of the
molecular physiology of this parasite. However, the translational dynamics that link
steady-state mRNA with protein levels are not well understood. In this study, we
bridge this disconnect by measuring genome-wide translation using ribosome profiling,
through five stages of the P. falciparum blood phase developmental
cycle. Our findings show that transcription and translation are tightly coupled, with
overt translational control occurring for less than 10% of the transcriptome.
Translationally regulated genes are predominantly associated with merozoite egress
functions. We systematically define mRNA 5′ leader sequences, and 3′
UTRs, as well as antisense transcripts, along with ribosome occupancy for each, and
establish that accumulation of ribosomes on 5′ leaders is a common transcript
feature. This work represents the highest resolution and broadest portrait of gene
expression and translation to date for this medically important parasite. DOI:http://dx.doi.org/10.7554/eLife.04106.001 The genome of an organism includes all of the genes or information necessary to
build, maintain, and replicate that organism. However, cells with the same
genome—such as a skin cell and a liver cell from the same person—can
look and behave very differently depending on which of the genes in their genomes
they express, and to what extent. For a gene to be expressed, its DNA is ‘transcribed’ to make an RNA
molecule, which is then ‘translated’ to make a protein. Efforts to
measure the transcription and translation processes in diseased cells, or in the
microorganisms that cause infections, may lead to new treatments and preventative
medicines. Such work is currently ongoing in the global effort to treat and prevent
malaria. Malaria is both preventable and curable, yet over 600,000 people are estimated to die
from this disease each year. The disease is caused by a single-celled parasite called
Plasmodium. Mosquitoes carry the parasites in their salivary
glands, and when a mosquito bites a human, these parasites are injected into the
bloodstream with the mosquito's saliva. Plasmodium parasites then
travel to and infect the liver, before bursting out of this tissue into the
bloodstream. Here, the parasites infect red blood cells and undergo rounds of
replication during which the symptoms of the disease are manifested. It is also
during this bloodstream phase that parasites can develop into forms capable of
infecting another mosquito and continuing the transmission cycle. The genes, RNA molecules, and proteins of the Plasmodium falciparum
parasite—which causes the most serious cases of malaria in humans—have
been cataloged to better understand the biology of this parasite. However, the
processes that control how, and when, an RNA transcript is translated into a protein
are not well understood. Now Caro et al. have uncovered which RNA molecules are being translated, and by how
much, during Plasmodium development within the blood. The
transcription and translation of genes in this parasite were found to be tightly
linked processes; the expression of only a few genes was controlled more by the
translation process than by transcription. These translationally regulated genes were
found mainly to be those that encode proteins involved in the parasite's exit from
the red blood cells and spread throughout the bloodstream. Caro et al. discovered that genetic regulation of the malaria parasite resembles a
preset genetic program, rather than a system that responds to changes and external
signals. As such, these findings suggest that targeting such a genetic program within
Plasmodium and preventing its implementation could prove an
effective strategy to curb the spread of malaria. DOI:http://dx.doi.org/10.7554/eLife.04106.002
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Affiliation(s)
- Florence Caro
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Vida Ahyong
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Miguel Betegon
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Joseph L DeRisi
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
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Doolan DL, Apte SH, Proietti C. Genome-based vaccine design: the promise for malaria and other infectious diseases. Int J Parasitol 2014; 44:901-13. [PMID: 25196370 DOI: 10.1016/j.ijpara.2014.07.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 07/30/2014] [Accepted: 07/31/2014] [Indexed: 01/08/2023]
Abstract
Vaccines are one of the most effective interventions to improve public health, however, the generation of highly effective vaccines for many diseases has remained difficult. Three chronic diseases that characterise these difficulties include malaria, tuberculosis and HIV, and they alone account for half of the global infectious disease burden. The whole organism vaccine approach pioneered by Jenner in 1796 and refined by Pasteur in 1857 with the "isolate, inactivate and inject" paradigm has proved highly successful for many viral and bacterial pathogens causing acute disease but has failed with respect to malaria, tuberculosis and HIV as well as many other diseases. A significant advance of the past decade has been the elucidation of the genomes, proteomes and transcriptomes of many pathogens. This information provides the foundation for new 21st Century approaches to identify target antigens for the development of vaccines, drugs and diagnostic tests. Innovative genome-based vaccine strategies have shown potential for a number of challenging pathogens, including malaria. We advocate that genome-based rational vaccine design will overcome the problem of poorly immunogenic, poorly protective vaccines that has plagued vaccine developers for many years.
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Affiliation(s)
- Denise L Doolan
- Infectious Diseases Programme, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4029, Australia.
| | - Simon H Apte
- Infectious Diseases Programme, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4029, Australia
| | - Carla Proietti
- Infectious Diseases Programme, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4029, Australia
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Vembar SS, Scherf A, Siegel TN. Noncoding RNAs as emerging regulators of Plasmodium falciparum virulence gene expression. Curr Opin Microbiol 2014; 20:153-61. [PMID: 25022240 PMCID: PMC4157322 DOI: 10.1016/j.mib.2014.06.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 06/15/2014] [Accepted: 06/20/2014] [Indexed: 11/15/2022]
Abstract
The eukaryotic unicellular pathogen Plasmodium falciparum tightly regulates gene expression, both during development and in adaptation to dynamic host environments. This regulation is evident in the mutually exclusive expression of members of clonally variant virulence multigene families. While epigenetic regulators have been selectively identified at active or repressed virulence genes, their specific recruitment remains a mystery. In recent years, noncoding RNAs (ncRNAs) have emerged as lynchpins of eukaryotic gene regulation; by binding to epigenetic regulators, they provide target specificity to otherwise non-specific enzyme complexes. Not surprisingly, there is great interest in understanding the role of ncRNA in P. falciparum, in particular, their contribution to the mutually exclusive expression of virulence genes. The current repertoire of P. falciparum ncRNAs includes, but is not limited to, subtelomeric ncRNAs, virulence gene-associated ncRNAs and natural antisense RNA transcripts. Continued improvement in high-throughput sequencing methods is sure to expand this repertoire. Here, we summarize recent advances in P. falciparum ncRNA biology, with an emphasis on ncRNA-mediated epigenetic modes of gene regulation.
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Affiliation(s)
- Shruthi S Vembar
- Biology of Host-Parasite Interactions Unit, Institut Pasteur, Paris, France; CNRS URA2581, Paris, France
| | - Artur Scherf
- Biology of Host-Parasite Interactions Unit, Institut Pasteur, Paris, France; CNRS URA2581, Paris, France
| | - T Nicolai Siegel
- Research Center for Infectious Diseases, University of Wuerzburg, Josef-Schneider-Str. 2/Bau D15, 97080 Wuerzburg, Germany.
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Deep profiling of the novel intermediate-size noncoding RNAs in intraerythrocytic Plasmodium falciparum. PLoS One 2014; 9:e92946. [PMID: 24713982 PMCID: PMC3979661 DOI: 10.1371/journal.pone.0092946] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 02/27/2014] [Indexed: 11/23/2022] Open
Abstract
Intermediate-size noncoding RNAs (is-ncRNAs) have been shown to play important regulatory roles in the development of several eukaryotic organisms. However, they have not been thoroughly explored in Plasmodium falciparum, which is the most virulent malaria parasite infecting human being. By using Illumina/Solexa paired-end sequencing of an is-ncRNA-specific library, we performed a systematic identification of novel is-ncRNAs in intraerythrocytic P. falciparum, strain 3D7. A total of 1,198 novel is-ncRNA candidates, including antisense, intergenic, and intronic is-ncRNAs, were identified. Bioinformatics analyses showed that the intergenic is-ncRNAs were the least conserved among different Plasmodium species, and antisense is-ncRNAs were more conserved than their sense counterparts. Twenty-two novel snoRNAs were identified, and eight potential novel classes of P. falciparum is-ncRNAs were revealed by clustering analysis. The expression of randomly selected novel is-ncRNAs was confirmed by RT-PCR and northern blotting assays. An obvious different expressional profile of the novel is-ncRNA between the early and late intraerythrocytic developmental stages of the parasite was observed. The expression levels of the antisense RNAs correlated with those of their cis-encoded sense RNA counterparts, suggesting that these is-ncRNAs are involved in the regulation of gene expression of the parasite. In conclusion, we accomplished a deep profiling analysis of novel is-ncRNAs in P. falciparum, analysed the conservation and structural features of these novel is-ncRNAs, and revealed their differential expression patterns during the development of the parasite. These findings provide important information for further functional characterisation of novel is-ncRNAs during the development of P. falciparum.
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Subudhi AK, Boopathi PA, Garg S, Middha S, Acharya J, Pakalapati D, Saxena V, Aiyaz M, Orekondy HB, Mugasimangalam RC, Sirohi P, Kochar SK, Kochar DK, Das A. Natural antisense transcripts in Plasmodium falciparum isolates from patients with complicated malaria. Exp Parasitol 2014; 141:39-54. [PMID: 24657575 DOI: 10.1016/j.exppara.2014.03.008] [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: 06/18/2013] [Revised: 02/17/2014] [Accepted: 03/05/2014] [Indexed: 10/25/2022]
Abstract
Mechanisms regulating gene expression in malaria parasites are not well understood. Little is known about how the parasite regulates its gene expression during transition from one developmental stage to another and in response to various environmental conditions. Parasites in a diseased host face environments which differ from the static, well adapted in vitro conditions. Parasites thus need to adapt quickly and effectively to these conditions by establishing transcriptional states which are best suited for better survival. With the discovery of natural antisense transcripts (NATs) in this parasite and considering the various proposed mechanisms by which NATs might regulate gene expression, it has been speculated that these might be playing a critical role in gene regulation. We report here the diversity of NATs in this parasite, using isolates taken directly from patients with differing clinical symptoms caused by malaria infection. Using a custom designed strand specific whole genome microarray, a total of 797 NATs targeted against annotated loci have been detected. Out of these, 545 NATs are unique to this study. The majority of NATs were positively correlated with the expression pattern of the sense transcript. However, 96 genes showed a change in sense/antisense ratio on comparison between uncomplicated and complicated disease conditions. The antisense transcripts map to a broad range of biochemical/metabolic pathways, especially pathways pertaining to the central carbon metabolism and stress related pathways. Our data strongly suggests that a large group of NATs detected here are unannotated transcription units antisense to annotated gene models. The results reveal a previously unknown set of NATs that prevails in this parasite, their differential regulation in disease conditions and mapping to functionally well annotated genes. The results detailed here call for studies to deduce the possible mechanism of action of NATs, which would further help in understanding the in vivo pathological adaptations of these parasites.
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Affiliation(s)
- Amit Kumar Subudhi
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani, Rajasthan, India.
| | - P A Boopathi
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani, Rajasthan, India.
| | - Shilpi Garg
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani, Rajasthan, India.
| | - Sheetal Middha
- Department of Medicine, S.P. Medical College, Bikaner, Rajasthan, India.
| | - Jyoti Acharya
- Department of Medicine, S.P. Medical College, Bikaner, Rajasthan, India.
| | - Deepak Pakalapati
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani, Rajasthan, India.
| | - Vishal Saxena
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani, Rajasthan, India.
| | | | | | | | - Paramendra Sirohi
- Department of Medicine, S.P. Medical College, Bikaner, Rajasthan, India.
| | - Sanjay K Kochar
- Department of Medicine, S.P. Medical College, Bikaner, Rajasthan, India.
| | - Dhanpat K Kochar
- Rajasthan University of Health Sciences, Jaipur, Rajasthan, India.
| | - Ashis Das
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani, Rajasthan, India.
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Siegel TN, Hon CC, Zhang Q, Lopez-Rubio JJ, Scheidig-Benatar C, Martins RM, Sismeiro O, Coppée JY, Scherf A. Strand-specific RNA-Seq reveals widespread and developmentally regulated transcription of natural antisense transcripts in Plasmodium falciparum. BMC Genomics 2014; 15:150. [PMID: 24559473 PMCID: PMC4007998 DOI: 10.1186/1471-2164-15-150] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 02/06/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Advances in high-throughput sequencing have led to the discovery of widespread transcription of natural antisense transcripts (NATs) in a large number of organisms, where these transcripts have been shown to play important roles in the regulation of gene expression. Likewise, the existence of NATs has been observed in Plasmodium but our understanding towards their genome-wide distribution remains incomplete due to the limited depth and uncertainties in the level of strand specificity of previous datasets. RESULTS To gain insights into the genome-wide distribution of NATs in P. falciparum, we performed RNA-ligation based strand-specific RNA sequencing at unprecedented depth. Our data indicate that 78.3% of the genome is transcribed during blood-stage development. Moreover, our analysis reveals significant levels of antisense transcription from at least 24% of protein-coding genes and that while expression levels of NATs change during the intraerythrocytic developmental cycle (IDC), they do not correlate with the corresponding mRNA levels. Interestingly, antisense transcription is not evenly distributed across coding regions (CDSs) but strongly clustered towards the 3'-end of CDSs. Furthermore, for a significant subset of NATs, transcript levels correlate with mRNA levels of neighboring genes.Finally, we were able to identify the polyadenylation sites (PASs) for a subset of NATs, demonstrating that at least some NATs are polyadenylated. We also mapped the PASs of 3443 coding genes, yielding an average 3' untranslated region length of 523 bp. CONCLUSIONS Our strand-specific analysis of the P. falciparum transcriptome expands and strengthens the existing body of evidence that antisense transcription is a substantial phenomenon in P. falciparum. For a subset of neighboring genes we find that sense and antisense transcript levels are intricately linked while other NATs appear to be regulated independently of mRNA transcription. Our deep strand-specific dataset will provide a valuable resource for the precise determination of expression levels as it separates sense from antisense transcript levels, which we find to often significantly differ. In addition, the extensive novel data on 3' UTR length will allow others to perform searches for regulatory motifs in the UTRs and help understand post-translational regulation in P. falciparum.
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Affiliation(s)
- T Nicolai Siegel
- Biology of Host-Parasite Interactions Unit, Institut Pasteur, Paris, France.
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26
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Boopathi P, Subudhi AK, Garg S, Middha S, Acharya J, Pakalapati D, Saxena V, Aiyaz M, Chand B, Mugasimangalam RC, Kochar SK, Sirohi P, Kochar DK, Das A. Revealing natural antisense transcripts from Plasmodium vivax isolates: Evidence of genome regulation in complicated malaria. INFECTION GENETICS AND EVOLUTION 2013; 20:428-43. [DOI: 10.1016/j.meegid.2013.09.026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 09/24/2013] [Accepted: 09/25/2013] [Indexed: 01/08/2023]
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27
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Bunnik EM, Chung DWD, Hamilton M, Ponts N, Saraf A, Prudhomme J, Florens L, Le Roch KG. Polysome profiling reveals translational control of gene expression in the human malaria parasite Plasmodium falciparum. Genome Biol 2013; 14:R128. [PMID: 24267660 PMCID: PMC4053746 DOI: 10.1186/gb-2013-14-11-r128] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 11/22/2013] [Indexed: 12/02/2022] Open
Abstract
Background In eukaryotic organisms, gene expression is regulated at multiple levels during the processes of transcription and translation. The absence of a tight regulatory network for transcription in the human malaria parasite suggests that gene expression may largely be controlled at post-transcriptional and translational levels. Results In this study, we compare steady-state mRNA and polysome-associated mRNA levels of Plasmodium falciparum at different time points during its asexual cell cycle. For more than 30% of its genes, we observe a delay in peak transcript abundance in the polysomal fraction as compared to the steady-state mRNA fraction, suggestive of strong translational control. Our data show that key regulatory mechanisms could include inhibitory activity of upstream open reading frames and translational repression of the major virulence gene family by intronic transcripts. In addition, we observe polysomal mRNA-specific alternative splicing events and widespread transcription of non-coding transcripts. Conclusions These different layers of translational regulation are likely to contribute to a complex network that controls gene expression in this eukaryotic pathogen. Disrupting the mechanisms involved in such translational control could provide novel anti-malarial strategies.
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Wyse BA, Oshidari R, Jeffery DC, Yankulov KY. Parasite epigenetics and immune evasion: lessons from budding yeast. Epigenetics Chromatin 2013; 6:40. [PMID: 24252437 PMCID: PMC3843538 DOI: 10.1186/1756-8935-6-40] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 11/11/2013] [Indexed: 11/23/2022] Open
Abstract
The remarkable ability of many parasites to evade host immunity is the key to their success and pervasiveness. The immune evasion is directly linked to the silencing of the members of extended families of genes that encode for major parasite antigens. At any time only one of these genes is active. Infrequent switches to other members of the gene family help the parasites elude the immune system and cause prolonged maladies. For most pathogens, the detailed mechanisms of gene silencing and switching are poorly understood. On the other hand, studies in the budding yeast Saccharomyces cerevisiae have revealed similar mechanisms of gene repression and switching and have provided significant insights into the molecular basis of these phenomena. This information is becoming increasingly relevant to the genetics of the parasites. Here we summarize recent advances in parasite epigenetics and emphasize the similarities between S. cerevisiae and pathogens such as Plasmodium, Trypanosoma, Candida, and Pneumocystis. We also outline current challenges in the control and the treatment of the diseases caused by these parasites and link them to epigenetics and the wealth of knowledge acquired from budding yeast.
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Affiliation(s)
| | | | | | - Krassimir Y Yankulov
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2 W1, Canada.
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Zhang X, Lii Y, Wu Z, Polishko A, Zhang H, Chinnusamy V, Lonardi S, Zhu JK, Liu R, Jin H. Mechanisms of small RNA generation from cis-NATs in response to environmental and developmental cues. MOLECULAR PLANT 2013; 6:704-15. [PMID: 23505223 PMCID: PMC3660955 DOI: 10.1093/mp/sst051] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 02/28/2013] [Indexed: 05/18/2023]
Abstract
A large proportion of eukaryotic genomes is transcribed from both positive and negative strands of DNA and thus may generate overlapping sense and antisense transcripts. Some of these so-called natural antisense transcripts (NATs) are possibly co-regulated. When the overlapping sense and antisense transcripts are expressed at the same time in the same cell in response to various developmental and environmental cues; they may form double-stranded RNAs, which could be recognized by the small RNA biogenesis machinery and processed into small interfering RNAs (siRNAs). cis-NAT-derived siRNAs (nat-siRNAs) are present in plants, animals, and fungi. In plants, the presence of nat-siRNAs is supported not only by Northern blot and genetic analyses, but also by the fact that there is an overall sixfold enrichment of siRNAs in the overlapping regions of cis-NATs and 19%-29% of the siRNA-generating cis-NATs in plants give rise to siRNAs only in their overlapping regions. Silencing mediated by nat-siRNAs is one of the mechanisms for regulating the expression of the cis-NATs. This review focuses on challenging issues related to the biogenesis mechanisms as well as regulation and detection of nat-siRNAs. The advantages and limitations of new technologies for detecting cis-NATs, including direct RNA sequencing and strand-specific RNA sequencing, are also discussed.
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Affiliation(s)
- Xiaoming Zhang
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Yifan Lii
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Zhigang Wu
- Department of Botany and Plant Sciences and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Anton Polishko
- Computer Science and Engineering, Center for Plant Cell Biology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Huiming Zhang
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA
| | - Viswanathan Chinnusamy
- Division of Plant Physiology, Indian Agricultural Research Institute, New Delhi 110012, India
| | - Stefano Lonardi
- Computer Science and Engineering, Center for Plant Cell Biology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Jian-Kang Zhu
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA
- Shanghai Center for Plant Stress Biology and Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
- To whom correspondence should be addressed. H.J. E-mail , tel. +1-951-827-7995. R.L. E-mail . J.-k.Z. E-mail
| | - Renyi Liu
- Department of Botany and Plant Sciences and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
- To whom correspondence should be addressed. H.J. E-mail , tel. +1-951-827-7995. R.L. E-mail . J.-k.Z. E-mail
| | - Hailing Jin
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology and Institute for Integrative Genome Biology, University of California, Riverside, CA 92521, USA
- To whom correspondence should be addressed. H.J. E-mail , tel. +1-951-827-7995. R.L. E-mail . J.-k.Z. E-mail
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Schlarman MS, Roberts RN, Kariuki MM, LaCrue AN, Ou R, Beerntsen BT. PFE0565w, a Plasmodium falciparum protein expressed in salivary gland sporozoites. Am J Trop Med Hyg 2012; 86:943-54. [PMID: 22665598 DOI: 10.4269/ajtmh.2012.11-0797] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Because malaria is still a significant problem worldwide, additional control methods need to be developed. The Plasmodium sporozoite is a good target for control measures because it displays dual infectivity for both mosquito and vertebrate host tissues. The Plasmodium falciparum gene, PFE0565w, was chosen as a candidate for study based on data from PlasmoDB, the Plasmodium database, indicating that it is expressed both at the transcriptional and protein levels in sporozoites, likely encodes a putative surface protein, and may have a potential role in the invasion of host tissues. Additional sequence analysis shows that the PFE0565w protein has orthologs in other Plasmodium species, but none outside of the genus Plasmodium. PFE0565w expresses transcript during both the sporozoite and erythrocytic stages of the parasite life cycle, where an alternative transcript was discovered during the erythrocytic stages. Data show that transcript is not present during axenic exoerythrocytic stages. Despite transcript being present in several life cycle stages, the PFE0565w protein is present only during the salivary gland sporozoite stage. Because the PFE0565w protein is present in salivary gland sporozoites, it could be a novel candidate for a pre-erythrocytic stage vaccine.
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Affiliation(s)
- Maggie S Schlarman
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO 65211, USA.
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López-Barragán MJ, Lemieux J, Quiñones M, Williamson KC, Molina-Cruz A, Cui K, Barillas-Mury C, Zhao K, Su XZ. Directional gene expression and antisense transcripts in sexual and asexual stages of Plasmodium falciparum. BMC Genomics 2011; 12:587. [PMID: 22129310 PMCID: PMC3266614 DOI: 10.1186/1471-2164-12-587] [Citation(s) in RCA: 243] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 11/30/2011] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND It has been shown that nearly a quarter of the initial predicted gene models in the Plasmodium falciparum genome contain errors. Although there have been efforts to obtain complete cDNA sequences to correct the errors, the coverage of cDNA sequences on the predicted genes is still incomplete, and many gene models for those expressed in sexual or mosquito stages have not been validated. Antisense transcripts have widely been reported in P. falciparum; however, the extent and pattern of antisense transcripts in different developmental stages remain largely unknown. RESULTS We have sequenced seven bidirectional libraries from ring, early and late trophozoite, schizont, gametocyte II, gametocyte V, and ookinete, and four strand-specific libraries from late trophozoite, schizont, gametocyte II, and gametocyte V of the 3D7 parasites. Alignment of the cDNA sequences to the 3D7 reference genome revealed stage-specific antisense transcripts and novel intron-exon splicing junctions. Sequencing of strand-specific cDNA libraries suggested that more genes are expressed in one direction in gametocyte than in schizont. Alternatively spliced genes, antisense transcripts, and stage-specific expressed genes were also characterized. CONCLUSIONS It is necessary to continue to sequence cDNA from different developmental stages, particularly those of non-erythrocytic stages. The presence of antisense transcripts in some gametocyte and ookinete genes suggests that these antisense RNA may play an important role in gene expression regulation and parasite development. Future gene expression studies should make use of directional cDNA libraries. Antisense transcripts may partly explain the observed discrepancy between levels of mRNA and protein expression.
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Affiliation(s)
- María J López-Barragán
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, USA
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Kuss C, Gan CS, Gunalan K, Bozdech Z, Sze SK, Preiser PR. Quantitative proteomics reveals new insights into erythrocyte invasion by Plasmodium falciparum. Mol Cell Proteomics 2011; 11:M111.010645. [PMID: 22023809 DOI: 10.1074/mcp.m111.010645] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Differential expression of ligands in the human malaria parasite Plasmodium falciparum enables it to recognize different receptors on the erythrocyte surface, thereby providing alternative invasion pathways. Switching of invasion from using sialated to nonsialated erythrocyte receptors has been linked to the transcriptional activation of a single parasite ligand. We have used quantitative proteomics to show that in addition to this single known change, there are a significant number of changes in the expression of merozoite proteins that are regulated independent of transcription during invasion pathway switching. These results demonstrate a so far unrecognized mechanism by which the malaria parasite is able to adapt to variations in the host cell environment by post-transcriptional regulation.
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Affiliation(s)
- Claudia Kuss
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
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Limenitakis J, Soldati-Favre D. Functional genetics in Apicomplexa: potentials and limits. FEBS Lett 2011; 585:1579-88. [PMID: 21557944 DOI: 10.1016/j.febslet.2011.05.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 05/02/2011] [Accepted: 05/03/2011] [Indexed: 01/15/2023]
Abstract
The Apicomplexans are obligate intracellular protozoan parasites and the causative agents of severe diseases in humans and animals. Although complete genome sequences are available since many years and for several parasites, they are replete with putative genes of unassigned function. Forward and reverse genetic approaches are limited only to a few Apicomplexans that can either be propagated in vitro or in a convenient animal model. This review will compare and contrast the most recent strategies developed for the genetic manipulation of Plasmodium falciparum, Plasmodium berghei and Toxoplasma gondii that have taken advantage of the intrinsic features of their respective genomes. Efforts towards the improvement of the transfection efficiencies in malaria parasites, the development of approaches to study essential genes and the elaboration of high-throughput methods for the identification of gene function will be discussed.
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Affiliation(s)
- Julien Limenitakis
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, Geneva, Switzerland.
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Sorber K, Dimon MT, DeRisi JL. RNA-Seq analysis of splicing in Plasmodium falciparum uncovers new splice junctions, alternative splicing and splicing of antisense transcripts. Nucleic Acids Res 2011; 39:3820-35. [PMID: 21245033 PMCID: PMC3089446 DOI: 10.1093/nar/gkq1223] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Over 50% of genes in Plasmodium falciparum, the deadliest human malaria parasite, contain predicted introns, yet experimental characterization of splicing in this organism remains incomplete. We present here a transcriptome-wide characterization of intraerythrocytic splicing events, as captured by RNA-Seq data from four timepoints of a single highly synchronous culture. Gene model-independent analysis of these data in conjunction with publically available RNA-Seq data with HMMSplicer, an in-house developed splice site detection algorithm, revealed a total of 977 new 5' GU-AG 3' and 5 new 5' GC-AG 3' junctions absent from gene models and ESTs (11% increase to the current annotation). In addition, 310 alternative splicing events were detected in 254 (4.5%) genes, most of which truncate open reading frames. Splicing events antisense to gene models were also detected, revealing complex transcriptional arrangements within the parasite's transcriptome. Interestingly, antisense introns overlap sense introns more than would be expected by chance, perhaps indicating a functional relationship between overlapping transcripts or an inherent organizational property of the transcriptome. Independent experimental validation confirmed over 30 new antisense and alternative junctions. Thus, this largest assemblage of new and alternative splicing events to date in Plasmodium falciparum provides a more precise, dynamic view of the parasite's transcriptome.
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Affiliation(s)
- Katherine Sorber
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
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35
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Abstract
Sexual reproduction enables eukaryotic organisms to reassort genetic diversity and purge deleterious mutations, producing better-fit progeny. Sex arose early and pervades eukaryotes. Fungal and parasite pathogens once thought asexual have maintained cryptic sexual cycles, including unisexual or parasexual reproduction. As pathogens become niche and host adapted, sex appears to specialize to promote inbreeding and clonality yet maintain outcrossing potential. During self-fertile sexual modes, sex itself may generate genetic diversity de novo. Mating-type loci govern fungal sexual identity; how parasites establish sexual identity is unknown. Comparing and contrasting fungal and parasite sex promises to reveal how microbial pathogens evolved and are evolving.
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Affiliation(s)
- Joseph Heitman
- Department of Molecular Genetics and Microbiology, Center for Microbial Pathogenesis, Duke University Medical Center, Durham, NC 27710, USA.
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Hughes KR, Philip N, Lucas Starnes G, Taylor S, Waters AP. From cradle to grave: RNA biology in malaria parasites. WILEY INTERDISCIPLINARY REVIEWS-RNA 2010; 1:287-303. [DOI: 10.1002/wrna.30] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Katie R. Hughes
- Division of Infection and Immunity, Faculty of Biomedical Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow G12 8TA, Scotland, UK
- Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow G12 8TA, Scotland, UK
| | - Nisha Philip
- Division of Infection and Immunity, Faculty of Biomedical Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow G12 8TA, Scotland, UK
- Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow G12 8TA, Scotland, UK
| | - G. Lucas Starnes
- Division of Infection and Immunity, Faculty of Biomedical Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow G12 8TA, Scotland, UK
- Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow G12 8TA, Scotland, UK
| | - Sonya Taylor
- Division of Infection and Immunity, Faculty of Biomedical Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow G12 8TA, Scotland, UK
- Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow G12 8TA, Scotland, UK
| | - Andrew P. Waters
- Division of Infection and Immunity, Faculty of Biomedical Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow G12 8TA, Scotland, UK
- Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, 120 University Place, Glasgow G12 8TA, Scotland, UK
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Abstract
One of the most important public health problems in the world today is the emergence and dissemination of drug-resistant malaria parasites. Plasmodium falciparum is the causative agent of the most lethal form of human malaria. New anti-malarial strategies are urgently required, and their design and development require the identification of potential therapeutic targets. However, the molecular mechanisms controlling the life cycle of the malaria parasite are still poorly understood. The published genome sequence of P. falciparum and previous studies have revealed that several homologues of eukaryotic signalling proteins, such as protein kinases, are relatively conserved. Protein kinases are now widely recognized as important drug targets in protozoan parasites. Cyclic AMP-dependent protein kinase (PKA) is implicated in numerous processes in mammalian cells, and the regulatory mechanisms of the cAMP pathway have been characterized. P. falciparum cAMP-dependent protein kinase plays an important role in the parasite's life cycle and thus represents an attractive target for the development of anti-malarial drugs. In this review, we focus on the P. falciparum cAMP/PKA pathway to provide new insights and an improved understanding of this signalling cascade.
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Matrajt M. Non-coding RNA in apicomplexan parasites. Mol Biochem Parasitol 2010; 174:1-7. [PMID: 20566348 DOI: 10.1016/j.molbiopara.2010.06.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Revised: 05/29/2010] [Accepted: 06/01/2010] [Indexed: 11/28/2022]
Abstract
In recent years it has became evident that the transcriptome of most species has little protein-coding capacity and that the abundance of non-coding RNA was previously overlooked. Non-coding RNAs were initially thought to be transcriptional noise, however, a growing number of studies is showing that many of these RNAs have important regulatory functions. Here, we review the progress done in apicomplexan parasites in this rapidly growing field.
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Affiliation(s)
- Mariana Matrajt
- Department of Microbiology and Molecular Genetics, University of Vermont, Stafford Hall, Room 306, 95 Carrigan Drive, Burlington, VT 05405, United States.
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Chromatin-mediated epigenetic regulation in the malaria parasite Plasmodium falciparum. EUKARYOTIC CELL 2010; 9:1138-49. [PMID: 20453074 DOI: 10.1128/ec.00036-10] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Malaria is a major public health problem in many developing countries, with the malignant tertian parasite Plasmodium falciparum causing the most malaria-associated mortality. Extensive research, especially with the advancement of genomics and transfection tools, has highlighted the fundamental importance of chromatin-mediated gene regulation in the developmental program of this early-branching eukaryote. The Plasmodium parasite genomes reveal the existence of both canonical and variant histones that make up the nucleosomes, as well as a full collection of conserved enzymes for chromatin remodeling and histone posttranslational modifications (PTMs). Recent studies have identified a wide array of both conserved and novel histone PTMs in P. falciparum, indicating the presence of a complex and divergent "histone code." Genome-wide analysis has begun to decipher the nucleosome landscape and histone modifications associated with the dynamic organization of chromatin structures during the parasite's life cycle. Focused studies on malaria-specific phenomena such as antigenic variation and red cell invasion pathways shed further light on the involvement of epigenetic mechanisms in these processes. Here we review our current understanding of chromatin-mediated gene regulation in malaria parasites, with specific reference to exemplar studies on antigenic variation and host cell invasion.
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Ruzanov P, Riddle DL. Deep SAGE analysis of the Caenorhabditis elegans transcriptome. Nucleic Acids Res 2010; 38:3252-62. [PMID: 20129939 PMCID: PMC2879516 DOI: 10.1093/nar/gkq035] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We employed the Tag-seq technique to generate global transcription profiles for different strains and life stages of the nematode C. elegans. Tag-seq generates cDNA tags as does Serial Analysis of Gene Expression (SAGE), but the method yields a much larger number of tags, generating much larger data sets than SAGE. We examined differences in the performance of SAGE and Tag-seq by comparing gene expression data for 13 pairs of libraries. We identified genes for which expression was consistently changed in long-lived worms. Additional genes emerged in the deeper Tag-seq profiles, including several ‘signature’ genes found among those zup-regulated in long-lived dauer larvae (cki-1, aak-2 and daf-16). Fifty to sixty percent of the genes differentially expressed in daf-2(−) versus daf-2(+) adults had fragmentary or no functional annotation, suggesting the involvement of as yet unstudied pathways in aging. We were able to distinguish between changes in gene expression associated with altered genotype or altered growth conditions. We found 62 cases of possible mRNA isoform switching in the 13 Tag-seq libraries, whereas the 13 SAGE libraries allowed detection of only 15 such occurrences. We observed strong expression of anti-sense transcripts for several mitochondrial genes, but nuclear anti-sense transcripts were neither abundant nor consistently expressed among the libraries.
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Affiliation(s)
- Peter Ruzanov
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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Rodriguez-Soca Y, Munteanu CR, Dorado J, Rabuñal J, Pazos A, González-Díaz H. Plasmod-PPI: A web-server predicting complex biopolymer targets in plasmodium with entropy measures of protein–protein interactions. POLYMER 2010. [DOI: 10.1016/j.polymer.2009.11.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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In vitro manipulation of gene expression in larval Schistosoma: a model for postgenomic approaches in Trematoda. Parasitology 2009; 137:463-83. [PMID: 19961646 DOI: 10.1017/s0031182009991302] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
With rapid developments in DNA and protein sequencing technologies, combined with powerful bioinformatics tools, a continued acceleration of gene identification in parasitic helminths is predicted, potentially leading to discovery of new drug and vaccine targets, enhanced diagnostics and insights into the complex biology underlying host-parasite interactions. For the schistosome blood flukes, with the recent completion of genome sequencing and comprehensive transcriptomic datasets, there has accumulated massive amounts of gene sequence data, for which, in the vast majority of cases, little is known about actual functions within the intact organism. In this review we attempt to bring together traditional in vitro cultivation approaches and recent emergent technologies of molecular genomics, transcriptomics and genetic manipulation to illustrate the considerable progress made in our understanding of trematode gene expression and function during development of the intramolluscan larval stages. Using several prominent trematode families (Schistosomatidae, Fasciolidae, Echinostomatidae), we have focused on the current status of in vitro larval isolation/cultivation as a source of valuable raw material supporting gene discovery efforts in model digeneans that include whole genome sequencing, transcript and protein expression profiling during larval development, and progress made in the in vitro manipulation of genes and their expression in larval trematodes using transgenic and RNA interference (RNAi) approaches.
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43
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Raabe CA, Sanchez CP, Randau G, Robeck T, Skryabin BV, Chinni SV, Kube M, Reinhardt R, Ng GH, Manickam R, Kuryshev VY, Lanzer M, Brosius J, Tang TH, Rozhdestvensky TS. A global view of the nonprotein-coding transcriptome in Plasmodium falciparum. Nucleic Acids Res 2009; 38:608-17. [PMID: 19864253 PMCID: PMC2811010 DOI: 10.1093/nar/gkp895] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Nonprotein-coding RNAs (npcRNAs) represent an important class of regulatory molecules that act in many cellular pathways. Here, we describe the experimental identification and validation of the small npcRNA transcriptome of the human malaria parasite Plasmodium falciparum. We identified 630 novel npcRNA candidates. Based on sequence and structural motifs, 43 of them belong to the C/D and H/ACA-box subclasses of small nucleolar RNAs (snoRNAs) and small Cajal body-specific RNAs (scaRNAs). We further observed the exonization of a functional H/ACA snoRNA gene, which might contribute to the regulation of ribosomal protein L7a gene expression. Some of the small npcRNA candidates are from telomeric and subtelomeric repetitive regions, suggesting their potential involvement in maintaining telomeric integrity and subtelomeric gene silencing. We also detected 328 cis-encoded antisense npcRNAs (asRNAs) complementary to P. falciparum protein-coding genes of a wide range of biochemical pathways, including determinants of virulence and pathology. All cis-encoded asRNA genes tested exhibit lifecycle-specific expression profiles. For all but one of the respective sense–antisense pairs, we deduced concordant patterns of expression. Our findings have important implications for a better understanding of gene regulatory mechanisms in P. falciparum, revealing an extended and sophisticated npcRNA network that may control the expression of housekeeping genes and virulence factors.
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Affiliation(s)
- Carsten A Raabe
- Institute of Experimental Pathology, ZMBE, University of Muenster, Von-Esmarch-Str. 56, 48149 Muenster, Germany
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Baum J, Papenfuss AT, Mair GR, Janse CJ, Vlachou D, Waters AP, Cowman AF, Crabb BS, de Koning-Ward TF. Molecular genetics and comparative genomics reveal RNAi is not functional in malaria parasites. Nucleic Acids Res 2009; 37:3788-98. [PMID: 19380379 PMCID: PMC2699523 DOI: 10.1093/nar/gkp239] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Revised: 03/30/2009] [Accepted: 03/30/2009] [Indexed: 01/02/2023] Open
Abstract
Techniques for targeted genetic disruption in Plasmodium, the causative agent of malaria, are currently intractable for those genes that are essential for blood stage development. The ability to use RNA interference (RNAi) to silence gene expression would provide a powerful means to gain valuable insight into the pathogenic blood stages but its functionality in Plasmodium remains controversial. Here we have used various RNA-based gene silencing approaches to test the utility of RNAi in malaria parasites and have undertaken an extensive comparative genomics search using profile hidden Markov models to clarify whether RNAi machinery exists in malaria. These investigative approaches revealed that Plasmodium lacks the enzymology required for RNAi-based ablation of gene expression and indeed no experimental evidence for RNAi was observed. In its absence, the most likely explanations for previously reported RNAi-mediated knockdown are either the general toxicity of introduced RNA (with global down-regulation of gene expression) or a specific antisense effect mechanistically distinct from RNAi, which will need systematic analysis if it is to be of use as a molecular genetic tool for malaria parasites.
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Affiliation(s)
- Jake Baum
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia, Instituto de Medicina Molecular, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal, Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands, Division of Infection and Immunity, Institute of Biomedical Life Sciences & Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, G12 8TA, Scotland, UK, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne 3004 and Deakin University, Waurn Ponds, Victoria 3217, Australia
| | - Anthony T. Papenfuss
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia, Instituto de Medicina Molecular, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal, Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands, Division of Infection and Immunity, Institute of Biomedical Life Sciences & Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, G12 8TA, Scotland, UK, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne 3004 and Deakin University, Waurn Ponds, Victoria 3217, Australia
| | - Gunnar R. Mair
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia, Instituto de Medicina Molecular, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal, Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands, Division of Infection and Immunity, Institute of Biomedical Life Sciences & Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, G12 8TA, Scotland, UK, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne 3004 and Deakin University, Waurn Ponds, Victoria 3217, Australia
| | - Chris J. Janse
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia, Instituto de Medicina Molecular, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal, Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands, Division of Infection and Immunity, Institute of Biomedical Life Sciences & Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, G12 8TA, Scotland, UK, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne 3004 and Deakin University, Waurn Ponds, Victoria 3217, Australia
| | - Dina Vlachou
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia, Instituto de Medicina Molecular, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal, Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands, Division of Infection and Immunity, Institute of Biomedical Life Sciences & Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, G12 8TA, Scotland, UK, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne 3004 and Deakin University, Waurn Ponds, Victoria 3217, Australia
| | - Andrew P. Waters
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia, Instituto de Medicina Molecular, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal, Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands, Division of Infection and Immunity, Institute of Biomedical Life Sciences & Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, G12 8TA, Scotland, UK, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne 3004 and Deakin University, Waurn Ponds, Victoria 3217, Australia
| | - Alan F. Cowman
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia, Instituto de Medicina Molecular, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal, Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands, Division of Infection and Immunity, Institute of Biomedical Life Sciences & Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, G12 8TA, Scotland, UK, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne 3004 and Deakin University, Waurn Ponds, Victoria 3217, Australia
| | - Brendan S. Crabb
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia, Instituto de Medicina Molecular, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal, Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands, Division of Infection and Immunity, Institute of Biomedical Life Sciences & Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, G12 8TA, Scotland, UK, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne 3004 and Deakin University, Waurn Ponds, Victoria 3217, Australia
| | - Tania F. de Koning-Ward
- The Walter & Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia, Instituto de Medicina Molecular, Av. Prof. Egas Moniz, 1649-028 Lisboa, Portugal, Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre, Leiden, The Netherlands, Division of Infection and Immunity, Institute of Biomedical Life Sciences & Wellcome Centre for Molecular Parasitology, Glasgow Biomedical Research Centre, University of Glasgow, G12 8TA, Scotland, UK, Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne 3004 and Deakin University, Waurn Ponds, Victoria 3217, Australia
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Transcriptome analysis of Schistosoma mansoni larval development using serial analysis of gene expression (SAGE). Parasitology 2009; 136:469-85. [PMID: 19265565 DOI: 10.1017/s0031182009005733] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARY Infection of the snail, Biomphalaria glabrata, by the free-swimming miracidial stage of the human blood fluke, Schistosoma mansoni, and its subsequent development to the parasitic sporocyst stage is critical to establishment of viable infections and continued human transmission. We performed a genome-wide expression analysis of the S. mansoni miracidia and developing sporocyst using Long Serial Analysis of Gene Expression (LongSAGE). Five cDNA libraries were constructed from miracidia and in vitro cultured 6- and 20-day-old sporocysts maintained in sporocyst medium (SM) or in SM conditioned by previous cultivation with cells of the B. glabrata embryonic (Bge) cell line. We generated 21 440 SAGE tags and mapped 13 381 to the S. mansoni gene predictions (v4.0e) either by estimating theoretical 3' UTR lengths or using existing 3' EST sequence data. Overall, 432 transcripts were found to be differentially expressed amongst all 5 libraries. In total, 172 tags were differentially expressed between miracidia and 6-day conditioned sporocysts and 152 were differentially expressed between miracidia and 6-day unconditioned sporocysts. In addition, 53 and 45 tags, respectively, were differentially expressed in 6-day and 20-day cultured sporocysts, due to the effects of exposure to Bge cell-conditioned medium.
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Sriwilaijaroen N, Boonma S, Attasart P, Pothikasikorn J, Panyim S, Noonpakdee W. Inhibition of Plasmodium falciparum proliferation in vitro by double-stranded RNA directed against malaria histone deacetylase. Biochem Biophys Res Commun 2009; 381:144-7. [PMID: 19338767 DOI: 10.1016/j.bbrc.2009.01.165] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Accepted: 01/23/2009] [Indexed: 10/21/2022]
Abstract
Acetylation and deacetylation of histones play important roles in transcription regulation, cell cycle progression and development events. The steady state status of histone acetylation is controlled by a dynamic equilibrium between competing histone acetylase and deacetylase (HDAC). We have used long PfHDAC-1 double-stranded (ds)RNA to interfere with its cognate mRNA expression and determined the effect on malaria parasite growth and development. Chloroquine- and pyrimethamine-resistant Plasmodium falciparum K1 strain was exposed to 1-25 microg of dsRNA/ml of culture for 48 h and growth was determined by [3H]-hypoxanthine incorporation and microscopic examination. Parasite culture treated with 10 microg/ml pfHDAC-1 dsRNA exhibited 47% growth inhibition when compared with either untreated control or culture treated with an unrelated dsRNA. PfHDAC-1 dsRNA specifically blocked maturation of trophozoite to schizont stages and decreased PfHDAC-1 transcript 44% in treated trophozoites. These results indicate the potential of HDAC-1 as a target for development of novel antimalarials.
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Affiliation(s)
- N Sriwilaijaroen
- Faculty of Medicine, Thammasat University (Rangsit Campus), Pathumthani 12120, Thailand
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47
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Patterns of gene-specific and total transcriptional activity during the Plasmodium falciparum intraerythrocytic developmental cycle. EUKARYOTIC CELL 2009; 8:327-38. [PMID: 19151330 DOI: 10.1128/ec.00340-08] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The relationships among gene regulatory mechanisms in the malaria parasite Plasmodium falciparum throughout its asexual intraerythrocytic developmental cycle (IDC) remain poorly understood. To investigate the level and nature of transcriptional activity and its role in controlling gene expression during the IDC, we performed nuclear run-on on whole-transcriptome samples from time points throughout the IDC and found a peak in RNA polymerase II-dependent transcriptional activity related to both the number of nuclei per parasite and variable transcriptional activity per nucleus over time. These differential total transcriptional activity levels allowed the calculation of the absolute transcriptional activities of individual genes from gene-specific nuclear run-on hybridization data. For half of the genes analyzed, sense-strand transcriptional activity peaked at the same time point as total activity. The antisense strands of several genes were substantially transcribed. Comparison of the transcriptional activity of the sense strand of each gene to its steady-state RNA abundance across the time points assayed revealed both correlations and discrepancies, implying transcriptional and posttranscriptional regulation, respectively. Our results demonstrate that such comparisons can effectively indicate gene regulatory mechanisms in P. falciparum and suggest that genes with diverse transcriptional activity levels and patterns combine to produce total transcriptional activity levels tied to parasite development during the IDC.
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48
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Brick K, Watanabe J, Pizzi E. Core promoters are predicted by their distinct physicochemical properties in the genome of Plasmodium falciparum. Genome Biol 2008; 9:R178. [PMID: 19094208 PMCID: PMC2646282 DOI: 10.1186/gb-2008-9-12-r178] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Revised: 11/03/2008] [Accepted: 12/18/2008] [Indexed: 11/23/2022] Open
Abstract
A method is presented to computationally identify core promoters in the Plasmodium falciparum genome using only DNA physicochemical properties. Little is known about the structure and distinguishing features of core promoters in Plasmodium falciparum. In this work, we describe the first method to computationally identify core promoters in this AT-rich genome. This prediction algorithm uses solely DNA physicochemical properties as descriptors. Our results add to a growing body of evidence that a physicochemical code for eukaryotic genomes plays a crucial role in core promoter recognition.
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Affiliation(s)
- Kevin Brick
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate - Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Rome, Italy.
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49
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Horrocks P, Wong E, Russell K, Emes RD. Control of gene expression in Plasmodium falciparum - ten years on. Mol Biochem Parasitol 2008; 164:9-25. [PMID: 19110008 DOI: 10.1016/j.molbiopara.2008.11.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2008] [Revised: 11/25/2008] [Accepted: 11/26/2008] [Indexed: 01/24/2023]
Abstract
Ten years ago this journal published a review with an almost identical title detailing how the then recent introduction of transfection technology had advanced our understanding of the molecular control of transcriptional processes in Plasmodium falciparum, particularly in terms of promoter structure and function. In the succeeding years, sequencing of several Plasmodium spp. genomes and application of high throughput global postgenomic technologies have proven as significant, if not more, as has the ability to genetically manipulate these parasites in dissecting the molecular control of gene expression. Here we aim to review our current understanding of the control of gene expression in P. falciparum, including evidence available from other Plasmodium spp. and apicomplexan parasites. Specifically, however, we will address the current polarised debate regarding the level at which control is mediated, and attempt to identify some of the challenges this field faces in the next 10 years.
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Affiliation(s)
- Paul Horrocks
- Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, United Kingdom.
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50
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Abstract
The persistence of the human malaria parasite Plasmodium falciparum during blood stage proliferation in its host depends on the successive expression of variant molecules at the surface of infected erythrocytes. This variation is mediated by the differential control of a family of surface molecules termed PfEMP1 encoded by approximately 60 var genes. Each individual parasite expresses a single var gene at a time, maintaining all other members of the family in a transcriptionally silent state. PfEMP1/var enables parasitized erythrocytes to adhere within the microvasculature, resulting in severe disease. This review highlights key regulatory mechanisms thought to be critical for monoallelic expression of var genes. Antigenic variation is orchestrated by epigenetic factors including monoallelic var transcription at separate spatial domains at the nuclear periphery, differential histone marks on otherwise identical var genes, and var silencing mediated by telomeric heterochromatin. In addition, controversies surrounding var genetic elements in antigenic variation are discussed.
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Affiliation(s)
- Artur Scherf
- Biology of Host-Parasite Interactions Unit, CNRS URA2581, Institut Pasteur 75724 Paris, France.
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