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Ashby EC, Havens JL, Rollosson LM, Hardin J, Schulz D. Chemical Inhibition of Bromodomain Proteins in Insect-Stage African Trypanosomes Perturbs Silencing of the Variant Surface Glycoprotein Repertoire and Results in Widespread Changes in the Transcriptome. Microbiol Spectr 2023; 11:e0014723. [PMID: 37097159 PMCID: PMC10269879 DOI: 10.1128/spectrum.00147-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 04/04/2023] [Indexed: 04/26/2023] Open
Abstract
The eukaryotic protozoan parasite Trypanosoma brucei is transmitted by the tsetse fly to both humans and animals, where it causes a fatal disease called African trypanosomiasis. While the parasite lacks canonical DNA sequence-specific transcription factors, it does possess histones, histone modifications, and proteins that write, erase, and read histone marks. Chemical inhibition of chromatin-interacting bromodomain proteins has previously been shown to perturb bloodstream specific trypanosome processes, including silencing of the variant surface glycoprotein (VSG) genes and immune evasion. Transcriptomic changes that occur in bromodomain-inhibited bloodstream parasites mirror many of the changes that occur as parasites developmentally progress from the bloodstream to the insect stage. We performed transcriptome sequencing (RNA-seq) time courses to determine the effects of chemical bromodomain inhibition in insect-stage parasites using the compound I-BET151. We found that treatment with I-BET151 causes large changes in the transcriptome of insect-stage parasites and also perturbs silencing of VSG genes. The transcriptomes of bromodomain-inhibited parasites share some features with early metacyclic-stage parasites in the fly salivary gland, implicating bromodomain proteins as important for regulating transcript levels for developmentally relevant genes. However, the downregulation of surface procyclin protein that typically accompanies developmental progression is absent in bromodomain-inhibited insect-stage parasites. We conclude that chemical modulation of bromodomain proteins causes widespread transcriptomic changes in multiple trypanosome life cycle stages. Understanding the gene-regulatory processes that facilitate transcriptome remodeling in this highly diverged eukaryote may shed light on how these mechanisms evolved. IMPORTANCE The disease African trypanosomiasis imposes a severe human and economic burden for communities in sub-Saharan Africa. The parasite that causes the disease is transmitted to the bloodstream of a human or ungulate via the tsetse fly. Because the environments of the fly and the bloodstream differ, the parasite modulates the expression of its genes to accommodate two different lifestyles in these disparate niches. Perturbation of bromodomain proteins that interact with histone proteins around which DNA is wrapped (chromatin) causes profound changes in gene expression in bloodstream-stage parasites. This paper reports that gene expression is also affected by chemical bromodomain inhibition in insect-stage parasites but that the genes affected differ depending on life cycle stage. Because trypanosomes diverged early from model eukaryotes, an understanding of how trypanosomes regulate gene expression may lend insight into how gene-regulatory mechanisms evolved. This could also be leveraged to generate new therapeutic strategies.
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Affiliation(s)
- Ethan C. Ashby
- Department of Biology, Harvey Mudd College, Claremont, California, USA
| | | | | | - Johanna Hardin
- Department of Mathematics and Statistics, Pomona College, Claremont, California, USA
| | - Danae Schulz
- Department of Biology, Harvey Mudd College, Claremont, California, USA
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2
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Casas-Sanchez A, Ramaswamy R, Perally S, Haines LR, Rose C, Aguilera-Flores M, Portillo S, Verbeelen M, Hussain S, Smithson L, Yunta C, Lehane MJ, Vaughan S, van den Abbeele J, Almeida IC, Boulanger MJ, Acosta-Serrano Á. The Trypanosoma brucei MISP family of invariant proteins is co-expressed with BARP as triple helical bundle structures on the surface of salivary gland forms, but is dispensable for parasite development within the tsetse vector. PLoS Pathog 2023; 19:e1011269. [PMID: 36996244 PMCID: PMC10089363 DOI: 10.1371/journal.ppat.1011269] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 04/11/2023] [Accepted: 03/08/2023] [Indexed: 04/01/2023] Open
Abstract
Trypanosoma brucei spp. develop into mammalian-infectious metacyclic trypomastigotes inside tsetse salivary glands. Besides acquiring a variant surface glycoprotein (VSG) coat, little is known about the metacyclic expression of invariant surface antigens. Proteomic analyses of saliva from T. brucei-infected tsetse flies identified, in addition to VSG and Brucei Alanine-Rich Protein (BARP) peptides, a family of glycosylphosphatidylinositol (GPI)-anchored surface proteins herein named as Metacyclic Invariant Surface Proteins (MISP) because of its predominant expression on the surface of metacyclic trypomastigotes. The MISP family is encoded by five paralog genes with >80% protein identity, which are exclusively expressed by salivary gland stages of the parasite and peak in metacyclic stage, as shown by confocal microscopy and immuno-high resolution scanning electron microscopy. Crystallographic analysis of a MISP isoform (MISP360) and a high confidence model of BARP revealed a triple helical bundle architecture commonly found in other trypanosome surface proteins. Molecular modelling combined with live fluorescent microscopy suggests that MISP N-termini are potentially extended above the metacyclic VSG coat, and thus could be tested as a transmission-blocking vaccine target. However, vaccination with recombinant MISP360 isoform did not protect mice against a T. brucei infectious tsetse bite. Lastly, both CRISPR-Cas9-driven knock out and RNAi knock down of all MISP paralogues suggest they are not essential for parasite development in the tsetse vector. We suggest MISP may be relevant during trypanosome transmission or establishment in the vertebrate's skin.
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Affiliation(s)
- Aitor Casas-Sanchez
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Samïrah Perally
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Lee R. Haines
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Clair Rose
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Marcela Aguilera-Flores
- Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Susana Portillo
- Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | | | | | - Laura Smithson
- Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Cristina Yunta
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Michael J. Lehane
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Sue Vaughan
- Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | | | - Igor C. Almeida
- Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Martin J. Boulanger
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, Canada
| | - Álvaro Acosta-Serrano
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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3
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A multi-adenylate cyclase regulator at the flagellar tip controls African trypanosome transmission. Nat Commun 2022; 13:5445. [PMID: 36114198 PMCID: PMC9481589 DOI: 10.1038/s41467-022-33108-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 08/30/2022] [Indexed: 11/23/2022] Open
Abstract
Signaling from ciliary microdomains controls developmental processes in metazoans. Trypanosome transmission requires development and migration in the tsetse vector alimentary tract. Flagellar cAMP signaling has been linked to parasite social motility (SoMo) in vitro, yet uncovering control of directed migration in fly organs is challenging. Here we show that the composition of an adenylate cyclase (AC) complex in the flagellar tip microdomain is essential for tsetse salivary gland (SG) colonization and SoMo. Cyclic AMP response protein 3 (CARP3) binds and regulates multiple AC isoforms. CARP3 tip localization depends on the cytoskeletal protein FLAM8. Re-localization of CARP3 away from the tip microdomain is sufficient to abolish SoMo and fly SG colonization. Since intrinsic development is normal in carp3 and flam8 knock-out parasites, AC complex-mediated tip signaling specifically controls parasite migration and thereby transmission. Participation of several developmentally regulated receptor-type AC isoforms may indicate the complexity of the in vivo signals perceived. Trypanosomes can sense signal molecules and coordinate their movement in response to such signals, a phenomenon termed social motility (SoMo). Here, Bachmaier et al show that cyclic AMP response protein 3 (CARP3) localization to the flagellar tip and its interaction with a number of different adenylate cyclases is essential for migration to tsetse fly salivary glands and for SoMo, therewith linking SoMo and cAMP signaling to trypanosome transmission.
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Bishola Tshitenge T, Clayton C. The Trypanosoma brucei RNA-binding protein DRBD18 ensures correct mRNA trans splicing and polyadenylation patterns. RNA (NEW YORK, N.Y.) 2022; 28:1239-1262. [PMID: 35793904 PMCID: PMC9380746 DOI: 10.1261/rna.079258.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
The parasite Trypanosoma brucei grows as bloodstream forms in mammals, and as procyclic forms in tsetse flies. Transcription is polycistronic, all mRNAs are trans spliced, and polyadenylation sites are defined by downstream splicing signals. Expression regulation therefore depends heavily on post-transcriptional mechanisms. The RNA-binding protein DRBD18 was previously implicated in the export of some mRNAs from the nucleus in procyclic forms. It copurifies the outer ring of the nuclear pore, mRNA export factors and exon-junction-complex proteins. We show that for more than 200 mRNAs, DRBD18 depletion caused preferential accumulation of versions with shortened 3'-untranslated regions, arising from use of polyadenylation sites that were either undetectable or rarely seen in nondepleted cells. The shortened mRNAs were often, but not always, more abundant in depleted cells than the corresponding longer versions in normal cells. Their appearance was linked to the appearance of trans-spliced, polyadenylated RNAs containing only downstream 3'-untranslated region-derived sequences. Experiments with one mRNA suggested that nuclear retention alone, through depletion of MEX67, did not affect mRNA length, suggesting a specific effect of DRBD18 on processing. DRBD18-bound mRNAs were enriched in polypyrimidine tract motifs, and DRBD18 was found in both the nucleus and the cytoplasm. We therefore suggest that in the nucleus, DRBD18 might bind to polypyrimidine tracts in 3'-UTRs of mRNA precursors. Such binding might both prevent recognition of mRNA-internal polypyrimidine tracts by splicing factors, and promote export of the processed bound mRNAs to the cytosol.
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Affiliation(s)
| | - Christine Clayton
- Heidelberg University Center for Molecular Biology (ZMBH), D69120 Heidelberg, Germany
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5
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Zíková A. Mitochondrial adaptations throughout the Trypanosoma brucei life cycle. J Eukaryot Microbiol 2022; 69:e12911. [PMID: 35325490 DOI: 10.1111/jeu.12911] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/18/2022] [Accepted: 03/18/2022] [Indexed: 12/01/2022]
Abstract
The unicellular parasite Trypanosoma brucei has a digenetic life cycle that alternates between a mammalian host and an insect vector. During programmed development, this extracellular parasite encounters strikingly different environments that determine its energy metabolism. Functioning as a bioenergetic, biosynthetic, and signaling center, the single mitochondrion of T. brucei is drastically remodeled to support the dynamic cellular demands of the parasite. This manuscript will provide an up-to-date overview of how the distinct T. brucei developmental stages differ in their mitochondrial metabolic and bioenergetic pathways, with a focus on the electron transport chain, proline oxidation, TCA cycle, acetate production, and ATP generation. Although mitochondrial metabolic rewiring has always been simply viewed as a consequence of the differentiation process, the possibility that certain mitochondrial activities reinforce parasite differentiation will be explored.
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Affiliation(s)
- Alena Zíková
- Biology Centre CAS, Institute of Parasitology, University of South Bohemia, Faculty of Science, České Budějovice, Czech Republic
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6
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Bishola Tshitenge T, Reichert L, Liu B, Clayton C. Several different sequences are implicated in bloodstream-form-specific gene expression in Trypanosoma brucei. PLoS Negl Trop Dis 2022; 16:e0010030. [PMID: 35312693 PMCID: PMC8982893 DOI: 10.1371/journal.pntd.0010030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 04/05/2022] [Accepted: 03/03/2022] [Indexed: 12/30/2022] Open
Abstract
The parasite Trypanosoma brucei grows as bloodstream forms in mammalian hosts, and as procyclic forms in tsetse flies. In trypanosomes, gene expression regulation depends heavily on post-transcriptional mechanisms. Both the RNA-binding protein RBP10 and glycosomal phosphoglycerate kinase PGKC are expressed only in mammalian-infective forms. RBP10 targets procyclic-specific mRNAs for destruction, while PGKC is required for bloodstream-form glycolysis. Developmental regulation of both is essential: expression of either RBP10 or PGKC in procyclic forms inhibits their proliferation. We show that the 3’-untranslated region of the RBP10 mRNA is extraordinarily long—7.3kb—and were able to identify six different sequences, scattered across the untranslated region, which can independently cause bloodstream-form-specific expression. The 3’-untranslated region of the PGKC mRNA, although much shorter, still contains two different regions, of 125 and 153nt, that independently gave developmental regulation. No short consensus sequences were identified that were enriched either within these regulatory regions, or when compared with other mRNAs with similar regulation, suggesting that more than one regulatory RNA-binding protein is important for repression of mRNAs in procyclic forms. We also identified regions, including an AU repeat, that increased expression in bloodstream forms, or suppressed it in both forms. Trypanosome mRNAs that encode RNA-binding proteins often have extremely extended 3’-untranslated regions. We suggest that one function of this might be to act as a fail-safe mechanism to ensure correct regulation even if mRNA processing or expression of trans regulators is defective. The parasite Trypanosoma brucei causes sleeping sickness in humans, and nagana in cattle, and is transmitted by Tsetse flies. It grows in the bloodstream and tissue fluids of mammalian hosts, as "bloodstream forms", and as "procyclic forms" in the midgut of tsetse flies. Several hundred proteins are expressed in a stage-specific fashion, and this is essential for parasite survival in the different environments. RBP10 is an RNA-binding protein that is expressed only in bloodstream forms. It binds to procyclic-specific mRNAs, and causes their destruction. PGKC is an enzyme that is also specifically expressed in bloodstream forms. Developmental regulation of both is essential: expression of either RBP10 or PGKC in procyclic forms prevents their growth. The mRNAs encoding both proteins are very unstable in procyclic forms, and the sequences responsible are in an "untranslated region" of the mRNA—sequences that follow the part that codes for protein. We here show that the mRNA encoding PGKC has two regions that independently cause developmental regulation, and that the very long untranslated region of the RBP10 mRNA has no fewer than six regulatory regions, but there were no obvious similarities between them. We suggest that the presence of several different regulatory sequences in trypanosome mRNAs might be a fail-safe mechanism to ensure correct regulation.
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Affiliation(s)
| | - Lena Reichert
- Heidelberg University Center for Molecular Biology (ZMBH), Heidelberg, Germany
| | - Bin Liu
- Heidelberg University Center for Molecular Biology (ZMBH), Heidelberg, Germany
| | - Christine Clayton
- Heidelberg University Center for Molecular Biology (ZMBH), Heidelberg, Germany
- * E-mail:
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7
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Howick VM, Peacock L, Kay C, Collett C, Gibson W, Lawniczak MKN. Single-cell transcriptomics reveals expression profiles of Trypanosoma brucei sexual stages. PLoS Pathog 2022; 18:e1010346. [PMID: 35255094 PMCID: PMC8939820 DOI: 10.1371/journal.ppat.1010346] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 03/22/2022] [Accepted: 02/06/2022] [Indexed: 01/26/2023] Open
Abstract
Early diverging lineages such as trypanosomes can provide clues to the evolution of sexual reproduction in eukaryotes. In Trypanosoma brucei, the pathogen that causes Human African Trypanosomiasis, sexual reproduction occurs in the salivary glands of the insect host, but analysis of the molecular signatures that define these sexual forms is complicated because they mingle with more numerous, mitotically-dividing developmental stages. We used single-cell RNA-sequencing (scRNAseq) to profile 388 individual trypanosomes from midgut, proventriculus, and salivary glands of infected tsetse flies allowing us to identify tissue-specific cell types. Further investigation of salivary gland parasite transcriptomes revealed fine-scale changes in gene expression over a developmental progression from putative sexual forms through metacyclics expressing variant surface glycoprotein genes. The cluster of cells potentially containing sexual forms was characterized by high level transcription of the gamete fusion protein HAP2, together with an array of surface proteins and several genes of unknown function. We linked these expression patterns to distinct morphological forms using immunofluorescence assays and reporter gene expression to demonstrate that the kinetoplastid-conserved gene Tb927.10.12080 is exclusively expressed at high levels by meiotic intermediates and gametes. Further experiments are required to establish whether this protein, currently of unknown function, plays a role in gamete formation and/or fusion.
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Affiliation(s)
- Virginia M. Howick
- Institute of Biodiversity, Animal Health, and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, United Kingdom
- Parasites and Microbes Programme, Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Lori Peacock
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
- Bristol Veterinary School, University of Bristol, Langford, United Kingdom
| | - Chris Kay
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Clare Collett
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Wendy Gibson
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Mara K. N. Lawniczak
- Parasites and Microbes Programme, Wellcome Sanger Institute, Hinxton, United Kingdom
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8
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Hutchinson S, Foulon S, Crouzols A, Menafra R, Rotureau B, Griffiths AD, Bastin P. The establishment of variant surface glycoprotein monoallelic expression revealed by single-cell RNA-seq of Trypanosoma brucei in the tsetse fly salivary glands. PLoS Pathog 2021; 17:e1009904. [PMID: 34543350 PMCID: PMC8509897 DOI: 10.1371/journal.ppat.1009904] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 10/12/2021] [Accepted: 08/17/2021] [Indexed: 12/27/2022] Open
Abstract
The long and complex Trypanosoma brucei development in the tsetse fly vector culminates when parasites gain mammalian infectivity in the salivary glands. A key step in this process is the establishment of monoallelic variant surface glycoprotein (VSG) expression and the formation of the VSG coat. The establishment of VSG monoallelic expression is complex and poorly understood, due to the multiple parasite stages present in the salivary glands. Therefore, we sought to further our understanding of this phenomenon by performing single-cell RNA-sequencing (scRNA-seq) on these trypanosome populations. We were able to capture the developmental program of trypanosomes in the salivary glands, identifying populations of epimastigote, gamete, pre-metacyclic and metacyclic cells. Our results show that parasite metabolism is dramatically remodeled during development in the salivary glands, with a shift in transcript abundance from tricarboxylic acid metabolism to glycolytic metabolism. Analysis of VSG gene expression in pre-metacyclic and metacyclic cells revealed a dynamic VSG gene activation program. Strikingly, we found that pre-metacyclic cells contain transcripts from multiple VSG genes, which resolves to singular VSG gene expression in mature metacyclic cells. Single molecule RNA fluorescence in situ hybridisation (smRNA-FISH) of VSG gene expression following in vitro metacyclogenesis confirmed this finding. Our data demonstrate that multiple VSG genes are transcribed before a single gene is chosen. We propose a transcriptional race model governs the initiation of monoallelic expression. African trypanosomes are parasitic protists which cause endemic disease in sub-Saharan Africa. To evade mammalian immune responses the parasite has developed a system of antigenic variation, where the surface of the cell is covered in a tightly packed coat of variant surface glycoproteins (VSGs). Each cell expresses only one variant surface glycoprotein at a time, and this is periodically switched to evade new antibodies. The process of singular gene expression is termed monoallelic expression and this has two components, establishment and maintenance, i.e. how a single gene is selected for expression and how its singular expression is maintained throughout successive generations. The establishment of monoallelic VSG gene expression occurs in the salivary gland of the tsetse fly vector, although this process is not well understood. We used single cell gene expression profiling applied to thousands of single cells in the salivary gland of the fly. We show that in order to select a single gene, trypanosomes initially transcribe multiple VSGs before a single gene is selected for high-level expression. We propose a model where this process is driven by a race to accumulate transcription factors at a single VSG gene.
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Affiliation(s)
- Sebastian Hutchinson
- Trypanosome Cell Biology Unit and INSERM U1201, Institut Pasteur, Paris, France
- * E-mail:
| | - Sophie Foulon
- Laboratoire de Biochimie, CBI, ESPCI Paris, Université PSL, CNRS UMR 8231, Paris, France
| | - Aline Crouzols
- Trypanosome Cell Biology Unit and INSERM U1201, Institut Pasteur, Paris, France
| | - Roberta Menafra
- Laboratoire de Biochimie, CBI, ESPCI Paris, Université PSL, CNRS UMR 8231, Paris, France
| | - Brice Rotureau
- Trypanosome Cell Biology Unit and INSERM U1201, Institut Pasteur, Paris, France
| | - Andrew D. Griffiths
- Laboratoire de Biochimie, CBI, ESPCI Paris, Université PSL, CNRS UMR 8231, Paris, France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit and INSERM U1201, Institut Pasteur, Paris, France
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9
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Naguleswaran A, Fernandes P, Bevkal S, Rehmann R, Nicholson P, Roditi I. Developmental changes and metabolic reprogramming during establishment of infection and progression of Trypanosoma brucei brucei through its insect host. PLoS Negl Trop Dis 2021; 15:e0009504. [PMID: 34543277 PMCID: PMC8483307 DOI: 10.1371/journal.pntd.0009504] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 09/30/2021] [Accepted: 09/07/2021] [Indexed: 02/07/2023] Open
Abstract
Trypanosoma brucei ssp., unicellular parasites causing human and animal trypanosomiasis, are transmitted between mammals by tsetse flies. Periodic changes in variant surface glycoproteins (VSG), which form the parasite coat in the mammal, allow them to evade the host immune response. Different isolates of T. brucei show heterogeneity in their repertoires of VSG genes and have single nucleotide polymorphisms and indels that can impact on genome editing. T. brucei brucei EATRO1125 (AnTaR1 serodeme) is an isolate that is used increasingly often because it is pleomorphic in mammals and fly transmissible, two characteristics that have been lost by the most commonly used laboratory stocks. We present a genome assembly of EATRO1125, including contigs for the intermediate chromosomes and minichromosomes that serve as repositories of VSG genes. In addition, de novo transcriptome assemblies were performed using Illumina sequences from tsetse-derived trypanosomes. Reads of 150 bases enabled closely related members of multigene families to be discriminated. This revealed that the transcriptome of midgut-derived parasites is dynamic, starting with the expression of high affinity hexose transporters and glycolytic enzymes and then switching to proline uptake and catabolism. These changes resemble the transition from early to late procyclic forms in culture. Further metabolic reprogramming, including upregulation of tricarboxylic acid cycle enzymes, occurs in the proventriculus. Many transcripts upregulated in the salivary glands encode surface proteins, among them 7 metacyclic VSGs, multiple BARPs and GCS1/HAP2, a marker for gametes. A novel family of transmembrane proteins, containing polythreonine stretches that are predicted to be O-glycosylation sites, was also identified. Finally, RNA-Seq data were used to create an optimised annotation file with 5’ and 3’ untranslated regions accurately mapped for 9302 genes. We anticipate that this will be of use in identifying transcripts obtained by single cell sequencing technologies. Trypanosoma brucei ssp. are single-celled parasites that cause two tropical diseases: sleeping sickness in humans and nagana in domestic animals. Parasites survive in the host bloodstream because they periodically change their surface coats and also because they can switch from slender dividing forms to stumpy non-dividing forms. The latter can be transmitted to their second host, the tsetse fly. Although closely related, different geographical isolates differ in their repertoire of surface coats and have small, but important differences in their DNA sequences. In addition, laboratory strains that are transferred between mammals by needle passage lose the ability to produce stumpy forms and to infect flies. The isolate T. b. brucei EATRO1125 is often used for research as it produces stumpy forms and is fly transmissible. We provide an assembly of the genome of this isolate, including part of the repertoire of coat proteins, and a detailed analysis of the genes that the parasites express as they establish infection and progress through the fly. This has provided new insights into trypanosome biology. The combined genomic (DNA) and transcriptomic (RNA) data will be useful resources for the trypanosome research community.
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Affiliation(s)
| | - Paula Fernandes
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School of Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Shubha Bevkal
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School of Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Ruth Rehmann
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Pamela Nicholson
- Next Generation Sequencing Platform, University of Bern, Bern, Switzerland
| | - Isabel Roditi
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- * E-mail:
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10
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Single-cell transcriptomic analysis of bloodstream Trypanosoma brucei reconstructs cell cycle progression and developmental quorum sensing. Nat Commun 2021; 12:5268. [PMID: 34489460 PMCID: PMC8421343 DOI: 10.1038/s41467-021-25607-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 08/17/2021] [Indexed: 02/07/2023] Open
Abstract
Developmental steps in the trypanosome life-cycle involve transition between replicative and non-replicative forms specialised for survival in, and transmission between, mammalian and tsetse fly hosts. Here, using oligopeptide-induced differentiation in vitro, we model the progressive development of replicative 'slender' to transmissible 'stumpy' bloodstream form Trypanosoma brucei and capture the transcriptomes of 8,599 parasites using single cell transcriptomics (scRNA-seq). Using this framework, we detail the relative order of biological events during asynchronous development, profile dynamic gene expression patterns and identify putative regulators. We additionally map the cell cycle of proliferating parasites and position stumpy cell-cycle exit at early G1 before progression to a distinct G0 state. A null mutant for one transiently elevated developmental regulator, ZC3H20 is further analysed by scRNA-seq, identifying its point of failure in the developmental atlas. This approach provides a paradigm for the dissection of differentiation events in parasites, relevant to diverse transitions in pathogen biology.
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11
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Walsh B, Hill KL. Right place, right time: Environmental sensing and signal transduction directs cellular differentiation and motility in Trypanosoma brucei. Mol Microbiol 2021; 115:930-941. [PMID: 33434370 DOI: 10.1111/mmi.14682] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 11/29/2022]
Abstract
Trypanosoma brucei and other African trypanosomes are vector-borne parasites that cause substantial human suffering across sub-Saharan Africa. The T. brucei life cycle is punctuated by numerous developmental stages, each occurring in a specific environmental niche and characterized by a unique morphology, metabolism, surface protein coat, and gene expression profile. The environmental cues and signaling pathways that drive transitions between these stages remain incompletely understood. Recent studies have started to fill this gap in knowledge. Likewise, several new studies have expanded our understanding of parasite movement through specific tissues and the parasite's ability to alter movement in response to external cues. Life cycle stage differentiation and motility are intimately integrated phenomena, as parasites must be at the right place (i.e., within a specific environmental milieu) at the right time (i.e., when they are appropriately staged and preadapted for perceiving and responding to signals) in order to complete their life cycle. In this review, we highlight some of the recent work that has transformed our understanding of signaling events that control parasite differentiation and motility. Increased knowledge of T. brucei environmental sensing and signal transduction advances our understanding of parasite biology and may direct prospective chemotherapeutic and transmission blockade strategies that are critical to eradication efforts.
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Affiliation(s)
- Breanna Walsh
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA.,Medical Scientist Training Program, University of California Los Angeles, Los Angeles, CA, USA
| | - Kent L Hill
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA.,California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, USA
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12
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Gilabert Carbajo C, Cornell LJ, Madbouly Y, Lai Z, Yates PA, Tinti M, Tiengwe C. Novel aspects of iron homeostasis in pathogenic bloodstream form Trypanosoma brucei. PLoS Pathog 2021; 17:e1009696. [PMID: 34161395 PMCID: PMC8259959 DOI: 10.1371/journal.ppat.1009696] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 07/06/2021] [Accepted: 06/04/2021] [Indexed: 01/09/2023] Open
Abstract
Iron is an essential regulatory signal for virulence factors in many pathogens. Mammals and bloodstream form (BSF) Trypanosoma brucei obtain iron by receptor-mediated endocytosis of transferrin bound to receptors (TfR) but the mechanisms by which T. brucei subsequently handles iron remains enigmatic. Here, we analyse the transcriptome of T. brucei cultured in iron-rich and iron-poor conditions. We show that adaptation to iron-deprivation induces upregulation of TfR, a cohort of parasite-specific genes (ESAG3, PAGS), genes involved in glucose uptake and glycolysis (THT1 and hexokinase), endocytosis (Phosphatidic Acid Phosphatase, PAP2), and most notably a divergent RNA binding protein RBP5, indicative of a non-canonical mechanism for regulating intracellular iron levels. We show that cells depleted of TfR by RNA silencing import free iron as a compensatory survival strategy. The TfR and RBP5 iron response are reversible by genetic complementation, the response kinetics are similar, but the regulatory mechanisms are distinct. Increased TfR protein is due to increased mRNA. Increased RBP5 expression, however, occurs by a post-transcriptional feedback mechanism whereby RBP5 interacts with its own, and with PAP2 mRNAs. Further observations suggest that increased RBP5 expression in iron-deprived cells has a maximum threshold as ectopic overexpression above this threshold disrupts normal cell cycle progression resulting in an accumulation of anucleate cells and cells in G2/M phase. This phenotype is not observed with overexpression of RPB5 containing a point mutation (F61A) in its single RNA Recognition Motif. Our experiments shed new light on how T. brucei BSFs reorganise their transcriptome to deal with iron stress revealing the first iron responsive RNA binding protein that is co-regulated with TfR, is important for cell viability and iron homeostasis; two essential processes for successful proliferation.
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Affiliation(s)
- Carla Gilabert Carbajo
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, United Kingdom
| | - Lucy J. Cornell
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, United Kingdom
| | - Youssef Madbouly
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, United Kingdom
| | - Zhihao Lai
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, United Kingdom
| | - Phillip A. Yates
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Michele Tinti
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Calvin Tiengwe
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, United Kingdom
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13
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Melo do Nascimento L, Egler F, Arnold K, Papavasiliou N, Clayton C, Erben E. Functional insights from a surface antigen mRNA-bound proteome. eLife 2021; 10:e68136. [PMID: 33783358 PMCID: PMC8051951 DOI: 10.7554/elife.68136] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 03/18/2021] [Indexed: 01/13/2023] Open
Abstract
Trypanosoma brucei is the causative agent of human sleeping sickness. The parasites' variant surface glycoprotein (VSG) enables them to evade adaptive immunity via antigenic variation. VSG comprises 10% of total cell protein and the high stability of VSG mRNA is essential for trypanosome survival. To determine how VSG mRNA stability is maintained, we used mRNA affinity purification to identify all its associated proteins. CFB2 (cyclin F-box protein 2), an unconventional RNA-binding protein with an F-box domain, was specifically enriched with VSG mRNA. We demonstrate that CFB2 is essential for VSG mRNA stability, describe cis acting elements within the VSG 3'-untranslated region that regulate the interaction, identify trans-acting factors that are present in the VSG messenger ribonucleoprotein particle, and mechanistically explain how CFB2 stabilizes the mRNA of this key pathogenicity factor. Beyond T. brucei, the mRNP purification approach has the potential to supply detailed biological insight into metabolism of relatively abundant mRNAs in any eukaryote.
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Affiliation(s)
| | - Franziska Egler
- Centre for Molecular Biology of Heidelberg University (ZMBH)HeidelbergGermany
| | - Katharina Arnold
- Centre for Molecular Biology of Heidelberg University (ZMBH)HeidelbergGermany
| | - Nina Papavasiliou
- Division of Immune Diversity, Deutsche Krebsforschungszentrum (DKFZ)HeidelbergGermany
| | - Christine Clayton
- Centre for Molecular Biology of Heidelberg University (ZMBH)HeidelbergGermany
| | - Esteban Erben
- Centre for Molecular Biology of Heidelberg University (ZMBH)HeidelbergGermany
- Division of Immune Diversity, Deutsche Krebsforschungszentrum (DKFZ)HeidelbergGermany
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14
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APEX2 Proximity Proteomics Resolves Flagellum Subdomains and Identifies Flagellum Tip-Specific Proteins in Trypanosoma brucei. mSphere 2021; 6:6/1/e01090-20. [PMID: 33568455 PMCID: PMC8141408 DOI: 10.1128/msphere.01090-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Sleeping sickness is a neglected tropical disease caused by the protozoan parasite Trypanosoma brucei. The disease disrupts the sleep-wake cycle, leading to coma and death if left untreated. T. brucei motility, transmission, and virulence depend on its flagellum (cilium), which consists of several different specialized subdomains. Trypanosoma brucei is the protozoan parasite responsible for sleeping sickness, a lethal vector-borne disease. T. brucei has a single flagellum (cilium) that plays critical roles in transmission and pathogenesis. An emerging concept is that the flagellum is organized into subdomains, each having specialized composition and function. The overall flagellum proteome has been well studied, but a critical knowledge gap is the protein composition of individual subdomains. We have tested whether APEX-based proximity proteomics could be used to examine the protein composition of T. brucei flagellum subdomains. As APEX-based labeling has not previously been described in T. brucei, we first fused APEX2 to the DRC1 subunit of the nexin-dynein regulatory complex, a well-characterized axonemal complex. We found that DRC1-APEX2 directs flagellum-specific biotinylation, and purification of biotinylated proteins yields a DRC1 “proximity proteome” having good overlap with published proteomes obtained from purified axonemes. Having validated the use of APEX2 in T. brucei, we next attempted to distinguish flagellar subdomains by fusing APEX2 to a flagellar membrane protein that is restricted to the flagellum tip, AC1, and another one that is excluded from the tip, FS179. Fluorescence microscopy demonstrated subdomain-specific biotinylation, and principal-component analysis showed distinct profiles between AC1-APEX2 and FS179-APEX2. Comparing these two profiles allowed us to identify an AC1 proximity proteome that is enriched for tip proteins, including proteins involved in signaling. Our results demonstrate that APEX2-based proximity proteomics is effective in T. brucei and can be used to resolve the proteome composition of flagellum subdomains that cannot themselves be readily purified. IMPORTANCE Sleeping sickness is a neglected tropical disease caused by the protozoan parasite Trypanosoma brucei. The disease disrupts the sleep-wake cycle, leading to coma and death if left untreated. T. brucei motility, transmission, and virulence depend on its flagellum (cilium), which consists of several different specialized subdomains. Given the essential and multifunctional role of the T. brucei flagellum, there is need for approaches that enable proteomic analysis of individual subdomains. Our work establishes that APEX2 proximity labeling can, indeed, be implemented in the biochemical environment of T. brucei and has allowed identification of proximity proteomes for different flagellar subdomains that cannot be purified. This capacity opens the possibility to study the composition and function of other compartments. We expect this approach may be extended to other eukaryotic pathogens and will enhance the utility of T. brucei as a model organism to study ciliopathies, heritable human diseases in which cilium function is impaired.
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15
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Abstract
Trypanosoma brucei is unusually reliant on mRNA-binding proteins to control mRNA fate, because its protein-coding genes lack individual promoters. We here focus on three trypanosome RNA-binding proteins. ZC3H22 is specific to Tsetse fly forms, RBP9 is preferentially expressed in bloodstream forms; and DRBD7 is constitutively expressed. Depletion of RBP9 or DRBD7 did not affect bloodstream-form trypanosome growth. ZC3H22 depletion from procyclic forms caused cell clumping, decreased expression of genes required for cell growth and proliferation, and increased expression of some epimastigote markers. Apart from decreases in mRNAs encoding enzymes of glucose metabolism, levels of most ZC3H22-bound transcripts were unaffected by ZC3H22 depletion. We compared ZC3H22, RBP9 and DRBD7 RNA binding with that of 16 other RNA-binding proteins. ZC3H22, PUF3 and ERBP1 show a preference for ribosomal protein mRNAs. RBP9 preferentially binds mRNAs that are more abundant in bloodstream forms than in procyclic forms. RBP9, ZC3H5, ZC3H30 and DRBD7 prefer mRNAs with long coding regions; UBP1-associated mRNAs have long 3′-untranslated regions; and RRM1 prefers mRNAs with long 3′or 5′-untranslated regions. We suggest that proteins that prefer long mRNAs may have relatively short or degenerate binding sites, and that preferences for A or U increase binding in untranslated regions.
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16
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Mwangi KW, Macharia RW, Bargul JL. Gene co-expression network analysis of Trypanosoma brucei in tsetse fly vector. Parasit Vectors 2021; 14:74. [PMID: 33482903 PMCID: PMC7821691 DOI: 10.1186/s13071-021-04597-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 01/13/2021] [Indexed: 01/14/2023] Open
Abstract
Background Trypanosoma brucei species are motile protozoan parasites that are cyclically transmitted by tsetse fly (genus Glossina) causing human sleeping sickness and nagana in livestock in sub-Saharan Africa. African trypanosomes display digenetic life cycle stages in the tsetse fly vector and in their mammalian host. Experimental work on insect-stage trypanosomes is challenging because of the difficulty in setting up successful in vitro cultures. Therefore, there is limited knowledge on the trypanosome biology during its development in the tsetse fly. Consequently, this limits the development of new strategies for blocking parasite transmission in the tsetse fly. Methods In this study, RNA-Seq data of insect-stage trypanosomes were used to construct a T. brucei gene co-expression network using the weighted gene co-expression analysis (WGCNA) method. The study identified significant enriched modules for genes that play key roles during the parasite’s development in tsetse fly. Furthermore, potential 3′ untranslated region (UTR) regulatory elements for genes that clustered in the same module were identified using the Finding Informative Regulatory Elements (FIRE) tool. Results A fraction of gene modules (12 out of 27 modules) in the constructed network were found to be enriched in functional roles associated with the cell division, protein biosynthesis, mitochondrion, and cell surface. Additionally, 12 hub genes encoding proteins such as RNA-binding protein 6 (RBP6), arginine kinase 1 (AK1), brucei alanine-rich protein (BARP), among others, were identified for the 12 significantly enriched gene modules. In addition, the potential regulatory elements located in the 3′ untranslated regions of genes within the same module were predicted. Conclusions The constructed gene co-expression network provides a useful resource for network-based data mining to identify candidate genes for functional studies. This will enhance understanding of the molecular mechanisms that underlie important biological processes during parasite’s development in tsetse fly. Ultimately, these findings will be key in the identification of potential molecular targets for disease control.![]()
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Affiliation(s)
- Kennedy W Mwangi
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya. .,Jomo Kenyatta University of Agriculture and Technology, P.O. BOX 62000-00200, Nairobi, Kenya.
| | | | - Joel L Bargul
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.,Jomo Kenyatta University of Agriculture and Technology, P.O. BOX 62000-00200, Nairobi, Kenya
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17
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Haindrich AC, Ernst V, Naguleswaran A, Oliveres QF, Roditi I, Rentsch D. Nutrient availability regulates proline/alanine transporters in Trypanosoma brucei. J Biol Chem 2021; 296:100566. [PMID: 33745971 PMCID: PMC8094907 DOI: 10.1016/j.jbc.2021.100566] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 03/09/2021] [Accepted: 03/17/2021] [Indexed: 11/23/2022] Open
Abstract
Trypanosoma brucei is a species of unicellular parasite that can cause severe diseases in livestock and humans, including African trypanosomiasis and Chagas disease. Adaptation to diverse environments and changes in nutritional conditions is essential for T. brucei to establish an infection when changing hosts or during invasion of different host tissues. One such adaptation is the ability of T. brucei to rapidly switch its energy metabolism from glucose metabolism in the mammalian blood to proline catabolism in the insect stages and vice versa. However, the mechanisms that support the parasite's response to nutrient availability remain unclear. Using RNAseq and qRT-PCR, we investigated the response of T. brucei to amino acid or glucose starvation and found increased mRNA levels of several amino acid transporters, including all genes of the amino acid transporter AAT7-B subgroup. Functional characterization revealed that AAT7-B members are plasma membrane-localized in T. brucei and when expressed in Saccharomyces cerevisiae supported the uptake of proline, alanine, and cysteine, while other amino acids were poorly recognized. All AAT7-B members showed a preference for proline, which is transported with high or low affinity. RNAi-mediated AAT7-B downregulation resulted in a reduction of intracellular proline concentrations and growth arrest under low proline availability in cultured procyclic form parasites. Taken together, these results suggest a role of AAT7-B transporters in the response of T. brucei to proline starvation and proline catabolism.
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Affiliation(s)
| | - Viona Ernst
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | | | | | - Isabel Roditi
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Doris Rentsch
- Institute of Plant Sciences, University of Bern, Bern, Switzerland.
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18
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Qasim M, Xiao H, He K, Omar MAA, Liu F, Ahmed S, Li F. Genetic engineering and bacterial pathogenesis against the vectorial capacity of mosquitoes. Microb Pathog 2020; 147:104391. [PMID: 32679245 DOI: 10.1016/j.micpath.2020.104391] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/05/2020] [Accepted: 07/09/2020] [Indexed: 12/19/2022]
Abstract
Mosquitoes are the main vector of multiple diseases worldwide and transmit viral (malaria, chikungunya, encephalitis, yellow fever, as well as dengue fever), as well as bacterial diseases (tularemia). To manage the outbreak of mosquito populations, various management programs include the application of chemicals, followed by biological and genetic control. Here we aimed to focus on the role of bacterial pathogenesis and molecular tactics for the management of mosquitoes and their vectorial capacity. Bacterial pathogenesis and molecular manipulations have a substantial impact on the biology of mosquitoes, and both strategies change the gene expression and regulation of disease vectors. The strategy for genetic modification is also proved to be excellent for the management of mosquitoes, which halt the development of population via incompatibility of different sex. Therefore, the purpose of the present discussion is to illustrate the impact of both approaches against the vectorial capacity of mosquitoes. Moreover, it could be helpful to understand the relationship of insect-pathogen and to manage various insect vectors as well as diseases.
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Affiliation(s)
- Muhammad Qasim
- Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou, 310058, China.
| | - Huamei Xiao
- Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou, 310058, China; College of Life Sciences and Resource Environment, Key Laboratory of Crop Growth and Development Regulation of Jiangxi Province, Yichun University, Yichun, 336000, China
| | - Kang He
- Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Mohamed A A Omar
- Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Feiling Liu
- Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Sohail Ahmed
- Department of Entomology, University of Agriculture, Faisalabad, 38040, Pakistan
| | - Fei Li
- Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, College of Agriculture & Biotechnology, Zhejiang University, Hangzhou, 310058, China.
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19
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Melo do Nascimento L, Terrao M, Marucha KK, Liu B, Egler F, Clayton C. The RNA-associated proteins MKT1 and MKT1L form alternative PBP1-containing complexes in Trypanosoma brucei. J Biol Chem 2020; 295:10940-10955. [PMID: 32532821 DOI: 10.1074/jbc.ra120.013306] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/03/2020] [Indexed: 01/20/2023] Open
Abstract
Control of gene expression in kinetoplastids such as trypanosomes depends heavily on RNA-binding proteins that influence mRNA decay and translation. We previously showed that the trypanosome protein MKT1 forms a multicomponent protein complex: MKT1 interacts with PBP1, which in turn recruits LSM12 and poly(A)-binding protein. MKT1 is recruited to mRNAs by sequence-specific RNA-binding proteins, resulting in stabilization of the bound mRNA. We here show that PBP1, LSM12, and a 117-residue protein, XAC1 (Tb927.7.2780), are present in complexes that contain either MKT1 or an MKT1-like protein, MKT1L (Tb927.10.1490). All five proteins are present predominantly in the complexes, and we found evidence for a minor subset of complexes containing both MKT1 and MKT1L. XAC1-containing complexes reproducibly contained RNA-binding proteins that were previously found associated with MKT1. Moreover, XAC1- or MKT1-containing complexes specifically recruited one of the two poly(A)-binding proteins, PABP2, and one of the six cap-binding translation initiation complexes, EIF4E6-EIF4G5. Yeast two-hybrid assay results indicated that MKT1 directly interacts with EIF4G5. MKT1-PBP1 complexes can therefore interact with mRNAs via their poly(A) tails and caps, as well as through sequence-specific RNA-binding proteins. Correspondingly, MKT1 is associated with many mRNAs, although not with those encoding ribosomal proteins. Meanwhile, MKT1L resembles MKT1 at the C terminus but additionally features an N-terminal extension with low-complexity regions. Although MKT1L depletion inhibited cell proliferation, we found no evidence that it specifically interacts with RNA-binding proteins or mRNA. We speculate that MKT1L may compete with MKT1 for PBP1 binding and thereby modulate the function of MKT1-containing complexes.
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Affiliation(s)
| | - Monica Terrao
- Heidelberg University Centre for Molecular Biology (ZMBH), Heidelberg, Germany
| | | | - Bin Liu
- Heidelberg University Centre for Molecular Biology (ZMBH), Heidelberg, Germany
| | - Franziska Egler
- Heidelberg University Centre for Molecular Biology (ZMBH), Heidelberg, Germany
| | - Christine Clayton
- Heidelberg University Centre for Molecular Biology (ZMBH), Heidelberg, Germany
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20
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Doleželová E, Kunzová M, Dejung M, Levin M, Panicucci B, Regnault C, Janzen CJ, Barrett MP, Butter F, Zíková A. Cell-based and multi-omics profiling reveals dynamic metabolic repurposing of mitochondria to drive developmental progression of Trypanosoma brucei. PLoS Biol 2020; 18:e3000741. [PMID: 32520929 PMCID: PMC7307792 DOI: 10.1371/journal.pbio.3000741] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 06/22/2020] [Accepted: 05/27/2020] [Indexed: 12/23/2022] Open
Abstract
Mitochondrial metabolic remodeling is a hallmark of the Trypanosoma brucei digenetic life cycle because the insect stage utilizes a cost-effective oxidative phosphorylation (OxPhos) to generate ATP, while bloodstream cells switch to aerobic glycolysis. Due to difficulties in acquiring enough parasites from the tsetse fly vector, the dynamics of the parasite's metabolic rewiring in the vector have remained obscure. Here, we took advantage of in vitro-induced differentiation to follow changes at the RNA, protein, and metabolite levels. This multi-omics and cell-based profiling showed an immediate redirection of electron flow from the cytochrome-mediated pathway to an alternative oxidase (AOX), an increase in proline consumption, elevated activity of complex II, and certain tricarboxylic acid (TCA) cycle enzymes, which led to mitochondrial membrane hyperpolarization and increased reactive oxygen species (ROS) levels. Interestingly, these ROS molecules appear to act as signaling molecules driving developmental progression because ectopic expression of catalase, a ROS scavenger, halted the in vitro-induced differentiation. Our results provide insights into the mechanisms of the parasite's mitochondrial rewiring and reinforce the emerging concept that mitochondria act as signaling organelles through release of ROS to drive cellular differentiation.
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Affiliation(s)
- Eva Doleželová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Michaela Kunzová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Mario Dejung
- Institute of Molecular Biology (IMB), Mainz, Germany
| | - Michal Levin
- Institute of Molecular Biology (IMB), Mainz, Germany
| | - Brian Panicucci
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Clément Regnault
- Welcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Christian J. Janzen
- Welcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Michael P. Barrett
- Department of Cell and Developmental Biology, Biocenter, University Wuerzburg, Wuerzburg, Germany
| | - Falk Butter
- Institute of Molecular Biology (IMB), Mainz, Germany
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
- * E-mail:
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21
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Single-cell RNA sequencing of Trypanosoma brucei from tsetse salivary glands unveils metacyclogenesis and identifies potential transmission blocking antigens. Proc Natl Acad Sci U S A 2020; 117:2613-2621. [PMID: 31964820 PMCID: PMC7007551 DOI: 10.1073/pnas.1914423117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Tsetse-transmitted African trypanosomes must develop into mammalian-infectious metacyclic cells in the fly's salivary glands (SGs) before transmission to a new host. The molecular mechanisms that underlie this developmental process, known as metacyclogenesis, are poorly understood. Blocking the few metacyclic parasites deposited in saliva from further development in the mammal could prevent disease. To obtain an in-depth perspective of metacyclogenesis, we performed single-cell RNA sequencing (scRNA-seq) from a pool of 2,045 parasites collected from infected tsetse SGs. Our data revealed three major cell clusters that represent the epimastigote, and pre- and mature metacyclic trypanosome developmental stages. Individual cell level data also confirm that the metacyclic pool is diverse, and that each parasite expresses only one of the unique metacyclic variant surface glycoprotein (mVSG) coat protein transcripts identified. Further clustering of cells revealed a dynamic transcriptomic and metabolic landscape reflective of a developmental program leading to infectious metacyclic forms preadapted to survive in the mammalian host environment. We describe the expression profile of proteins that regulate gene expression and that potentially play a role in metacyclogenesis. We also report on a family of nonvariant surface proteins (Fam10) and demonstrate surface localization of one member (named SGM1.7) on mature metacyclic parasites. Vaccination of mice with recombinant SGM1.7 reduced parasitemia early in the infection. Future studies are warranted to investigate Fam10 family proteins as potential trypanosome transmission blocking vaccine antigens. Our experimental approach is translationally relevant for developing strategies to prevent other insect saliva-transmitted parasites from infecting and causing disease in mammalian hosts.
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22
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Sloan MA, Brooks K, Otto TD, Sanders MJ, Cotton JA, Ligoxygakis P. Transcriptional and genomic parallels between the monoxenous parasite Herpetomonas muscarum and Leishmania. PLoS Genet 2019; 15:e1008452. [PMID: 31710597 PMCID: PMC6872171 DOI: 10.1371/journal.pgen.1008452] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 11/21/2019] [Accepted: 10/01/2019] [Indexed: 12/20/2022] Open
Abstract
Trypanosomatid parasites are causative agents of important human and animal diseases such as sleeping sickness and leishmaniasis. Most trypanosomatids are transmitted to their mammalian hosts by insects, often belonging to Diptera (or true flies). These are called dixenous trypanosomatids since they infect two different hosts, in contrast to those that infect just insects (monoxenous). However, it is still unclear whether dixenous and monoxenous trypanosomatids interact similarly with their insect host, as fly-monoxenous trypanosomatid interaction systems are rarely reported and under-studied-despite being common in nature. Here we present the genome of monoxenous trypanosomatid Herpetomonas muscarum and discuss its transcriptome during in vitro culture and during infection of its natural insect host Drosophila melanogaster. The H. muscarum genome is broadly syntenic with that of human parasite Leishmania major. We also found strong similarities between the H. muscarum transcriptome during fruit fly infection, and those of Leishmania during sand fly infections. Overall this suggests Drosophila-Herpetomonas is a suitable model for less accessible insect-trypanosomatid host-parasite systems such as sand fly-Leishmania.
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Affiliation(s)
- Megan A. Sloan
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Karen Brooks
- The Wellcome Sanger Institute, Wellcome Genome Campus, Hixton, Cambridgeshire, United Kingdom
| | - Thomas D. Otto
- The Wellcome Sanger Institute, Wellcome Genome Campus, Hixton, Cambridgeshire, United Kingdom
| | - Mandy J. Sanders
- The Wellcome Sanger Institute, Wellcome Genome Campus, Hixton, Cambridgeshire, United Kingdom
| | - James A. Cotton
- The Wellcome Sanger Institute, Wellcome Genome Campus, Hixton, Cambridgeshire, United Kingdom
| | - Petros Ligoxygakis
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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23
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Abstract
Trypanosomes have complex life cycles within which there are both proliferative and differentiation cell divisions. The coordination of the cell cycle to achieve these different divisions is critical for the parasite to infect both host and vector. From studying the regulation of the proliferative cell cycle of the Trypanosoma brucei procyclic life cycle stage, three subcycles emerge that control the duplication and segregation of ( a) the nucleus, ( b) the kinetoplast, and ( c) a set of cytoskeletal structures. We discuss how the clear dependency relationships within these subcycles, and the potential for cross talk between them, are likely required for overall cell cycle coordination. Finally, we look at the implications this interdependence has for proliferative and differentiation divisions through the T. brucei life cycle and in related parasitic trypanosomatid species.
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Affiliation(s)
- Richard J. Wheeler
- Nuffield Department of Medicine, University of Oxford, Oxford OX1 3SY, United Kingdom
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Jack D. Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
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24
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Terrao M, Marucha KK, Mugo E, Droll D, Minia I, Egler F, Braun J, Clayton C. The suppressive cap-binding complex factor 4EIP is required for normal differentiation. Nucleic Acids Res 2019; 46:8993-9010. [PMID: 30124912 PMCID: PMC6158607 DOI: 10.1093/nar/gky733] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/01/2018] [Indexed: 12/27/2022] Open
Abstract
Trypanosoma brucei live in mammals as bloodstream forms and in the Tsetse midgut as procyclic forms. Differentiation from one form to the other proceeds via a growth-arrested stumpy form with low messenger RNA (mRNA) content and translation. The parasites have six eIF4Es and five eIF4Gs. EIF4E1 pairs with the mRNA-binding protein 4EIP but not with any EIF4G. EIF4E1 and 4EIP each inhibit expression when tethered to a reporter mRNA, but while tethered EIF4E1 suppresses only when 4EIP is present, suppression by tethered 4EIP does not require the interaction with EIF4E1. In growing bloodstream forms, 4EIP is preferentially associated with unstable mRNAs. Bloodstream- or procyclic-form trypanosomes lacking 4EIP have only a marginal growth disadvantage. Bloodstream forms without 4EIP are, however, defective in translation suppression during stumpy-form differentiation and cannot subsequently convert to growing procyclic forms. Intriguingly, the differentiation defect can be complemented by a truncated 4EIP that does not interact with EIF4E1. In contrast, bloodstream forms lacking EIF4E1 have a growth defect, stumpy formation seems normal, but they appear unable to grow as procyclic forms. We suggest that 4EIP and EIF4E1 fine-tune mRNA levels in growing cells, and that 4EIP contributes to translation suppression during differentiation to the stumpy form.
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Affiliation(s)
- Monica Terrao
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Kevin K Marucha
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Elisha Mugo
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Dorothea Droll
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Igor Minia
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Franziska Egler
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Johanna Braun
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Christine Clayton
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
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25
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Abstract
In trypanosomes, RNA polymerase II transcription is polycistronic and individual mRNAs are excised by trans-splicing and polyadenylation. The lack of individual gene transcription control is compensated by control of mRNA processing, translation and degradation. Although the basic mechanisms of mRNA decay and translation are evolutionarily conserved, there are also unique aspects, such as the existence of six cap-binding translation initiation factor homologues, a novel decapping enzyme and an mRNA stabilizing complex that is recruited by RNA-binding proteins. High-throughput analyses have identified nearly a hundred regulatory mRNA-binding proteins, making trypanosomes valuable as a model system to investigate post-transcriptional regulation.
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Affiliation(s)
- Christine Clayton
- University of Heidelberg Center for Molecular Biology (ZMBH), Im Neuenheimer Feld 282, D69120 Heidelberg, Germany
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26
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Abstract
Parasites elicit several physiological changes in their host to enhance transmission. Little is known about the functional association between parasitism and microbiota-provisioned resources typically dedicated to animal hosts and how these goods may be rerouted to optimize parasite development. This study is the first to identify a specific symbiont-generated metabolite that impacts insect vector competence by facilitating parasite establishment and, thus, eventual transmission. Specifically, we demonstrate that the tsetse fly obligate mutualist Wigglesworthia provisions folate (vitamin B9) that pathogenic African trypanosomes exploit in an effort to successfully establish an infection in the vector’s MG. This process is essential for the parasite to complete its life cycle and be transmitted to a new vertebrate host. Disrupting metabolic contributions provided by the microbiota of arthropod disease vectors may fuel future innovative control strategies while also offering minimal nontarget effects. Many symbionts supplement their host’s diet with essential nutrients. However, whether these nutrients also enhance parasitism is unknown. In this study, we investigated whether folate (vitamin B9) production by the tsetse fly (Glossina spp.) essential mutualist, Wigglesworthia, aids auxotrophic African trypanosomes in completing their life cycle within this obligate vector. We show that the expression of Wigglesworthia folate biosynthesis genes changes with the progression of trypanosome infection within tsetse. The disruption of Wigglesworthia folate production caused a reduction in the percentage of flies that housed midgut (MG) trypanosome infections. However, decreased folate did not prevent MG trypanosomes from migrating to and establishing an infection in the fly’s salivary glands, thus suggesting that nutrient requirements vary throughout the trypanosome life cycle. We further substantiated that trypanosomes rely on symbiont-generated folate by feeding this vitamin to Glossina brevipalpis, which exhibits low trypanosome vector competency and houses Wigglesworthia incapable of producing folate. Folate-supplemented G. brevipalpis flies were significantly more susceptible to trypanosome infection, further demonstrating that this vitamin facilitates parasite infection establishment. Our cumulative results provide evidence that Wigglesworthia provides a key metabolite (folate) that is “hijacked” by trypanosomes to enhance their infectivity, thus indirectly impacting tsetse species vector competency. Parasite dependence on symbiont-derived micronutrients, which likely also occurs in other arthropod vectors, represents a relationship that may be exploited to reduce disease transmission.
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27
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Cayla M, Rojas F, Silvester E, Venter F, Matthews KR. African trypanosomes. Parasit Vectors 2019; 12:190. [PMID: 31036044 PMCID: PMC6489224 DOI: 10.1186/s13071-019-3355-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 02/26/2019] [Indexed: 12/15/2022] Open
Abstract
African trypanosomes cause human African trypanosomiasis and animal African trypanosomiasis. They are transmitted by tsetse flies in sub-Saharan Africa. Although most famous for their mechanisms of immune evasion by antigenic variation, there have been recent important studies that illuminate important aspects of the biology of these parasites both in their mammalian host and during passage through their tsetse fly vector. This Primer overviews current research themes focused on these parasites and discusses how these biological insights and the development of new technologies to interrogate gene function are being used in the search for new approaches to control the parasite. The new insights into the biology of trypanosomes in their host and vector highlight that we are in a ‘golden age’ of discovery for these fascinating parasites.
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Affiliation(s)
- Mathieu Cayla
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Federico Rojas
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Eleanor Silvester
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Frank Venter
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Keith R Matthews
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
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28
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Shaw S, DeMarco SF, Rehmann R, Wenzler T, Florini F, Roditi I, Hill KL. Flagellar cAMP signaling controls trypanosome progression through host tissues. Nat Commun 2019; 10:803. [PMID: 30778051 PMCID: PMC6379439 DOI: 10.1038/s41467-019-08696-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 01/18/2019] [Indexed: 02/07/2023] Open
Abstract
The unicellular parasite Trypanosoma brucei is transmitted between mammals by tsetse flies. Following the discovery that flagellar phosphodiesterase PDEB1 is required for trypanosomes to move in response to signals in vitro (social motility), we investigated its role in tsetse flies. Here we show that PDEB1 knockout parasites exhibit subtle changes in movement, reminiscent of bacterial chemotaxis mutants. Infecting flies with the knockout, followed by live confocal microscopy of fluorescent parasites within dual-labelled insect tissues, shows that PDEB1 is important for traversal of the peritrophic matrix, which separates the midgut lumen from the ectoperitrophic space. Without PDEB1, parasites are trapped in the lumen and cannot progress through the cycle. This demonstrates that the peritrophic matrix is a barrier that must be actively overcome and that the parasite’s flagellar cAMP signaling pathway facilitates this. Migration may depend on perception of chemotactic cues, which could stem from co-infecting parasites and/or the insect host. Trypanosoma brucei probably relies on chemotactic signals for movement through tsetse fly tissues, but the molecular basis is unknown. Here, the authors show that flagellar cAMP signaling is required for traversal of the peritrophic matrix and that, without it, parasites are trapped in the midgut lumen.
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Affiliation(s)
- Sebastian Shaw
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, CH-3012, Bern, Switzerland
| | - Stephanie F DeMarco
- Molecular Biology Institute, University of California, Los Angeles, CA, 90095, USA
| | - Ruth Rehmann
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012, Bern, Switzerland
| | - Tanja Wenzler
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012, Bern, Switzerland
| | - Francesca Florini
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, CH-3012, Bern, Switzerland
| | - Isabel Roditi
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012, Bern, Switzerland.
| | - Kent L Hill
- Molecular Biology Institute, University of California, Los Angeles, CA, 90095, USA. .,Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA. .,California NanoSystems Institute, University of California, Los Angeles, CA, 90095, USA.
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29
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Briggs E, Hamilton G, Crouch K, Lapsley C, McCulloch R. Genome-wide mapping reveals conserved and diverged R-loop activities in the unusual genetic landscape of the African trypanosome genome. Nucleic Acids Res 2018; 46:11789-11805. [PMID: 30304482 PMCID: PMC6294496 DOI: 10.1093/nar/gky928] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 09/25/2018] [Accepted: 10/05/2018] [Indexed: 01/09/2023] Open
Abstract
R-loops are stable RNA-DNA hybrids that have been implicated in transcription initiation and termination, as well as in telomere maintenance, chromatin formation, and genome replication and instability. RNA Polymerase (Pol) II transcription in the protozoan parasite Trypanosoma brucei is highly unusual: virtually all genes are co-transcribed from multigene transcription units, with mRNAs generated by linked trans-splicing and polyadenylation, and transcription initiation sites display no conserved promoter motifs. Here, we describe the genome-wide distribution of R-loops in wild type mammal-infective T. brucei and in mutants lacking RNase H1, revealing both conserved and diverged functions. Conserved localization was found at centromeres, rRNA genes and retrotransposon-associated genes. RNA Pol II transcription initiation sites also displayed R-loops, suggesting a broadly conserved role despite the lack of promoter conservation or transcription initiation regulation. However, the most abundant sites of R-loop enrichment were within the regions between coding sequences of the multigene transcription units, where the hybrids coincide with sites of polyadenylation and nucleosome-depletion. Thus, instead of functioning in transcription termination the most widespread localization of R-loops in T. brucei suggests a novel correlation with pre-mRNA processing. Finally, we find little evidence for correlation between R-loop localization and mapped sites of DNA replication initiation.
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Affiliation(s)
- Emma Briggs
- The Wellcome Centre for Molecular Parasitology, University of Glasgow, College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity and Inflammation, Sir Graeme Davies Building, 120 University Place, Glasgow G12 8TA, UK
| | - Graham Hamilton
- Glasgow Polyomics, University of Glasgow, Wolfson Wohl Cancer Research Centre, Garscube Estate, Switchback Rd, Bearsden, G61 1QH, UK
| | - Kathryn Crouch
- The Wellcome Centre for Molecular Parasitology, University of Glasgow, College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity and Inflammation, Sir Graeme Davies Building, 120 University Place, Glasgow G12 8TA, UK
| | - Craig Lapsley
- The Wellcome Centre for Molecular Parasitology, University of Glasgow, College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity and Inflammation, Sir Graeme Davies Building, 120 University Place, Glasgow G12 8TA, UK
| | - Richard McCulloch
- The Wellcome Centre for Molecular Parasitology, University of Glasgow, College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity and Inflammation, Sir Graeme Davies Building, 120 University Place, Glasgow G12 8TA, UK
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30
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Kariithi HM, Meki IK, Schneider DI, De Vooght L, Khamis FM, Geiger A, Demirbaş-Uzel G, Vlak JM, iNCE IA, Kelm S, Njiokou F, Wamwiri FN, Malele II, Weiss BL, Abd-Alla AMM. Enhancing vector refractoriness to trypanosome infection: achievements, challenges and perspectives. BMC Microbiol 2018; 18:179. [PMID: 30470182 PMCID: PMC6251094 DOI: 10.1186/s12866-018-1280-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
With the absence of effective prophylactic vaccines and drugs against African trypanosomosis, control of this group of zoonotic neglected tropical diseases depends the control of the tsetse fly vector. When applied in an area-wide insect pest management approach, the sterile insect technique (SIT) is effective in eliminating single tsetse species from isolated populations. The need to enhance the effectiveness of SIT led to the concept of investigating tsetse-trypanosome interactions by a consortium of researchers in a five-year (2013-2018) Coordinated Research Project (CRP) organized by the Joint Division of FAO/IAEA. The goal of this CRP was to elucidate tsetse-symbiome-pathogen molecular interactions to improve SIT and SIT-compatible interventions for trypanosomoses control by enhancing vector refractoriness. This would allow extension of SIT into areas with potential disease transmission. This paper highlights the CRP's major achievements and discusses the science-based perspectives for successful mitigation or eradication of African trypanosomosis.
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Affiliation(s)
- Henry M Kariithi
- Biotechnology Research Institute, Kenya Agricultural & Livestock Research Organization, P.O Box 57811, 00200, Kaptagat Rd, Loresho, Nairobi, Kenya
| | - Irene K Meki
- Insect Pest Control Laboratory, FAO/IAEA Agriculture & Biotechnology Laboratory, IAEA Laboratories Seibersdorf, A-2444 Seibersdorf, Austria
- Laboratory of Virology, Wageningen University and Research, Wageningen, 6708 PB The Netherlands
| | - Daniela I Schneider
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT 06510 USA
| | - Linda De Vooght
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
| | - Fathiya M Khamis
- International Centre of Insect Physiology and Ecology, P.O. Box 30772, 00100, Nairobi, Kenya
| | - Anne Geiger
- INTERTRYP, Institut de Recherche pour le Développement, University of Montpellier, Montpellier, France
| | - Guler Demirbaş-Uzel
- Insect Pest Control Laboratory, FAO/IAEA Agriculture & Biotechnology Laboratory, IAEA Laboratories Seibersdorf, A-2444 Seibersdorf, Austria
| | - Just M Vlak
- Laboratory of Virology, Wageningen University and Research, Wageningen, 6708 PB The Netherlands
| | - ikbal Agah iNCE
- Institute of Chemical, Environmental & Biological Engineering, Research Area Biochemical Technology, Vienna University of Technology, Gumpendorfer Straße 1a, 1060 Vienna, Austria
| | - Sorge Kelm
- Department of Medical Microbiology, Acıbadem Mehmet Ali Aydınlar University, School of Medicine, 34752, Ataşehir, Istanbul, Turkey
| | - Flobert Njiokou
- Centre for Biomolecular Interactions Bremen, Faculty for Biology & Chemistry, Universität Bremen, Bibliothekstraße 1, 28359 Bremen, Germany
| | - Florence N Wamwiri
- Laboratory of Parasitology and Ecology, Faculty of Sciences, Department of Animal Biology and Physiology, University of Yaoundé 1, Yaoundé, BP 812 Cameroon
| | - Imna I Malele
- Trypanosomiasis Research Centre, Kenya Agricultural & Livestock Research Organization, P.O. Box 362-00902, Kikuyu, Kenya
| | - Brian L Weiss
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT 06510 USA
| | - Adly M M Abd-Alla
- Molecular Department, Vector and Vector Borne Diseases Institute, Tanzania Veterinary Laboratory Agency, Majani Mapana, Off Korogwe Road, Box, 1026 Tanga, Tanzania
- Insect Pest Control Laboratory, FAO/IAEA Agriculture & Biotechnology Laboratory, IAEA Laboratories Seibersdorf, A-2444 Seibersdorf, Austria
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31
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Silvester E, Ivens A, Matthews KR. A gene expression comparison of Trypanosoma brucei and Trypanosoma congolense in the bloodstream of the mammalian host reveals species-specific adaptations to density-dependent development. PLoS Negl Trop Dis 2018; 12:e0006863. [PMID: 30307943 PMCID: PMC6199001 DOI: 10.1371/journal.pntd.0006863] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 10/23/2018] [Accepted: 09/21/2018] [Indexed: 12/19/2022] Open
Abstract
In the bloodstream of mammalian hosts Trypanosoma brucei undergoes well-characterised density-dependent growth control and developmental adaptation for transmission. This involves the differentiation from proliferative, morphologically ‘slender’ forms to quiescent ‘stumpy’ forms that preferentially infect the tsetse fly vector. Another important livestock trypanosome, Trypanosoma congolense, also undergoes density-dependent cell-cycle arrest although this is not linked to obvious morphological transformation. Here we have compared the gene expression profile of T. brucei and T. congolense during the ascending phase of the parasitaemia and at peak parasitaemia in mice, analysing species and developmental differences between proliferating and cell-cycle arrested forms. Despite underlying conservation of their quorum sensing signalling pathway, each species exhibits distinct profiles of gene regulation when analysed by orthogroup and cell surface phylome profiling. This analysis of peak parasitaemia T. congolense provides the first molecular signatures of potential developmental competence, assisting life cycle developmental studies in these important livestock parasites. Furthermore, comparison with T. brucei identifies candidate molecules from each species that may be important for their survival in the mammalian host, transmission or distinct tropism in the tsetse vector. Animal African trypanosomiases are important diseases of livestock in sub-Saharan Africa. Two of the responsible parasite species are Trypanosoma brucei and Trypanosoma congolense, both being blood-borne parasites transmitted by tsetse flies. In T. brucei there is a well-characterised developmental event in the bloodstream that prepares the parasite for tsetse transmission—the generation of morphologically stumpy forms. In contrast, Trypanosoma congolense does not undergo the same obvious morphological event, but does respond to parasite density in the mammalian bloodstream by accumulating as a cell cycle arrested form. This prompted us to explore the adaptations of T. congolense in response to cell density in blood and to compare this with T. brucei. The datasets generated, and their analysis, represent a first detailed transcriptional profile for T. congolense and also a new high-resolution analysis of the developmental forms of T. brucei in a mammalian host. Critically, the analysis also carefully characterised the biological material used for RNA-seq analysis with respect to cell cycle status, morphology and the expression (in the case of T. brucei) of PAD1 –a molecular marker for stumpy forms. The manuscript highlights clear differences in the developmental adaptation of each parasite species, with T. congolense showing less extreme adaptation at peak parasitaemia than T. brucei. Nonetheless, several predicted surface protein families in T. congolense are strongly upregulated at high parasite density in the bloodstream, which may represent adaptations for their transmission or survival.
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Affiliation(s)
- Eleanor Silvester
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Alasdair Ivens
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Keith R. Matthews
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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32
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Shi H, Butler K, Tschudi C. A single-point mutation in the RNA-binding protein 6 generates Trypanosoma brucei metacyclics that are able to progress to bloodstream forms in vitro. Mol Biochem Parasitol 2018; 224:50-56. [PMID: 30055184 PMCID: PMC6147148 DOI: 10.1016/j.molbiopara.2018.07.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/20/2018] [Accepted: 07/22/2018] [Indexed: 01/27/2023]
Abstract
We previously established an in vitro differentiation system based on the inducible expression of the RNA binding protein 6 (RBP6), which initiated differentiation of Trypanosoma brucei non-infectious procyclics to infectious metacyclics (MFs). However, further differentiation to bloodstream forms (BFs) required infection of mice. Here we report the serendipitous isolation of a single point mutation in RBP6 (Q109K), whose expression not only generated MFs, but purified MFs continued the developmental cycle in vitro to BFs expressing variant surface glycoprotein-2 (VSG-2), formerly known as VSG 221. This transition occurred over a period of 11 days and by RNA-Seq, VSG-2 was first measureable on day 1, whereas metacyclic VSGs were detected up to 8 days. We further showed that inducible expression of mutant RBP6 appeared to skip the intermediate epimastigote stage and we highlight the potential involvement of RBP33 in the establishment of metacyclics and in particular in the generation of metacyclics uncharacteristically arrested at the G2/M checkpoint.
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Affiliation(s)
- Huafang Shi
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, Connecticut 06520, USA
| | - Kiantra Butler
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, Connecticut 06520, USA
| | - Christian Tschudi
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, Connecticut 06520, USA.
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33
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Awuoche EO, Weiss BL, Mireji PO, Vigneron A, Nyambega B, Murilla G, Aksoy S. Expression profiling of Trypanosoma congolense genes during development in the tsetse fly vector Glossina morsitans morsitans. Parasit Vectors 2018; 11:380. [PMID: 29970164 PMCID: PMC6029126 DOI: 10.1186/s13071-018-2964-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Accepted: 06/20/2018] [Indexed: 02/07/2023] Open
Abstract
Background The tsetse transmitted parasitic flagellate Trypanosoma congolense causes animal African trypanosomosis (AAT) across sub-Saharan Africa. AAT negatively impacts agricultural, economic, nutritional and subsequently, health status of the affected populace. The molecular mechanisms that underlie T. congolense’s developmental program within tsetse are largely unknown due to considerable challenges with obtaining sufficient parasite cells to perform molecular studies. Methods In this study, we used RNA-seq to profile T. congolense gene expression during development in two distinct tsetse tissues, the cardia and proboscis. Indirect immunofluorescent antibody test (IFA) and confocal laser scanning microscope was used to localize the expression of a putative protein encoded by the hypothetical protein (TcIL3000_0_02370). Results Consistent with current knowledge, genes coding several variant surface glycoproteins (including metacyclic specific VSGs), and the surface coat protein, congolense epimastigote specific protein, were upregulated in parasites in the proboscis (PB-parasites). Additionally, our results indicate that parasites in tsetse’s cardia (C-parasites) and PB employ oxidative phosphorylation and amino acid metabolism for energy. Several genes upregulated in C-parasites encoded receptor-type adenylate cyclases, surface carboxylate transporter family proteins (or PADs), transport proteins, RNA-binding proteins and procyclin isoforms. Gene ontology analysis of products of genes upregulated in C-parasites showed enrichment of terms broadly associated with nucleotides, microtubules, cell membrane and its components, cell signaling, quorum sensing and several transport activities, suggesting that the parasites colonizing the cardia may monitor their environment and regulate their density and movement in this tissue. Additionally, cell surface protein (CSP) encoding genes associated with the Fam50 ‘GARP’, ‘iii’ and ‘i’ subfamilies were also significantly upregulated in C-parasites, suggesting that they are important for the long non-dividing trypomastigotes to colonize tsetse’s cardia. The putative products of genes that were upregulated in PB-parasites were linked to nucleosomes, cytoplasm and membrane-bound organelles, which suggest that parasites in this niche undergo cell division in line with prior findings. Most of the CSPs upregulated in PB-parasites were hypothetical, thus requiring further functional characterization. Expression of one such hypothetical protein (TcIL3000_0_02370) was analyzed using immunofluorescence and confocal laser scanning microscopy, which together revealed preferential expression of this protein on the entire surface coat of T. congolense parasite stages that colonize G. m. morsitans’ proboscis. Conclusion Collectively, our results provide insight into T. congolense gene expression profiles in distinct niches within the tsetse vector. Our results show that the hypothetical protein TcIL3000_0_02370, is expressed on the entire surface of the trypanosomes inhabiting tsetse’s proboscis. We discuss our results in terms of their relevance to disease transmission processes. Electronic supplementary material The online version of this article (10.1186/s13071-018-2964-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Erick O Awuoche
- Department of Biochemistry, Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya. .,Department of Biomedical Science and Technology, School of Public Health and Community Development, Maseno University, Private Bag, Maseno, Kenya. .,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA. .,Department of Agriculture, School of Agriculture and Food Science, Meru University of Science and Technology, Meru, Kenya.
| | - Brian L Weiss
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Paul O Mireji
- Department of Biochemistry, Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya.,Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA.,Centre for Geographic Medicine Research - Coast, Kenya Medical Research Institute, Kilifi, Kenya
| | - Aurélien Vigneron
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Benson Nyambega
- Department of Medical Biochemistry, School of Medicine, Maseno University, Private Bag, Maseno, Kenya
| | - Grace Murilla
- Department of Biochemistry, Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Serap Aksoy
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
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34
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Recent advances in trypanosomatid research: genome organization, expression, metabolism, taxonomy and evolution. Parasitology 2018; 146:1-27. [PMID: 29898792 DOI: 10.1017/s0031182018000951] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Unicellular flagellates of the family Trypanosomatidae are obligatory parasites of invertebrates, vertebrates and plants. Dixenous species are aetiological agents of a number of diseases in humans, domestic animals and plants. Their monoxenous relatives are restricted to insects. Because of the high biological diversity, adaptability to dramatically different environmental conditions, and omnipresence, these protists have major impact on all biotic communities that still needs to be fully elucidated. In addition, as these organisms represent a highly divergent evolutionary lineage, they are strikingly different from the common 'model system' eukaryotes, such as some mammals, plants or fungi. A number of excellent reviews, published over the past decade, were dedicated to specialized topics from the areas of trypanosomatid molecular and cell biology, biochemistry, host-parasite relationships or other aspects of these fascinating organisms. However, there is a need for a more comprehensive review that summarizing recent advances in the studies of trypanosomatids in the last 30 years, a task, which we tried to accomplish with the current paper.
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Naguleswaran A, Doiron N, Roditi I. RNA-Seq analysis validates the use of culture-derived Trypanosoma brucei and provides new markers for mammalian and insect life-cycle stages. BMC Genomics 2018; 19:227. [PMID: 29606092 PMCID: PMC5879877 DOI: 10.1186/s12864-018-4600-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 03/13/2018] [Indexed: 01/03/2023] Open
Abstract
Background Trypanosoma brucei brucei, the parasite causing Nagana in domestic animals, is closely related to the parasites causing sleeping sickness, but does not infect humans. In addition to its importance as a pathogen, the relative ease of genetic manipulation and an innate capacity for RNAi extend its use as a model organism in cell and infection biology. During its development in its mammalian and insect (tsetse fly) hosts, T. b. brucei passes through several different life-cycle stages. There are currently four life-cycle stages that can be cultured: slender forms and stumpy forms, which are equivalent to forms found in the mammal, and early and late procyclic forms, which are equivalent to forms in the tsetse midgut. Early procyclic forms show coordinated group movement (social motility) on semi-solid surfaces, whereas late procyclic forms do not. Results RNA-Seq was performed on biological replicates of each life-cycle stage. These constitute the first datasets for culture-derived slender and stumpy bloodstream forms and early and late procyclic forms. Expression profiles confirmed that genes known to be stage-regulated in the animal and insect hosts were also regulated in culture. Sequence reads of 100–125 bases provided sufficient precision to uncover differential expression of closely related genes. More than 100 transcripts showed peak expression in stumpy forms, including adenylate cyclases and several components of inositol metabolism. Early and late procyclic forms showed differential expression of 73 transcripts, a number of which encoded proteins that were previously shown to be stage-regulated. Moreover, two adenylate cyclases previously shown to reduce social motility are up-regulated in late procyclic forms. Conclusions This study validates the use of cultured bloodstream forms as alternatives to animal-derived parasites and yields new markers for all four stages. In addition to underpinning recent findings that early and late procyclic forms are distinct life-cycle stages, it could provide insights into the reasons for their different biological properties. Electronic supplementary material The online version of this article (10.1186/s12864-018-4600-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Nicholas Doiron
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012, Bern, Switzerland
| | - Isabel Roditi
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, CH-3012, Bern, Switzerland.
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Expression of the RNA-binding protein RBP10 promotes the bloodstream-form differentiation state in Trypanosoma brucei. PLoS Pathog 2017; 13:e1006560. [PMID: 28800584 PMCID: PMC5568443 DOI: 10.1371/journal.ppat.1006560] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 08/23/2017] [Accepted: 07/29/2017] [Indexed: 01/06/2023] Open
Abstract
In nearly all eukaryotes, cellular differentiation is governed by changes in transcription, and stabilized by chromatin and DNA modification. Gene expression control in the pathogen Trypanosoma brucei, in contrast, relies almost exclusively on post-transcriptional mechanisms, so RNA binding proteins must assume the burden that is usually borne by transcription factors. T. brucei multiply in the blood of mammals as bloodstream forms, and in the midgut of Tsetse flies as procyclic forms. We show here that a single RNA-binding protein, RBP10, promotes the bloodstream-form trypanosome differentiation state. Depletion of RBP10 from bloodstream-form trypanosomes gives cells that can grow only as procyclic forms; conversely, expression of RBP10 in procyclic forms converts them to bloodstream forms. RBP10 binds to procyclic-specific mRNAs containing an UAUUUUUU motif, targeting them for translation repression and destruction. Products of RBP10 target mRNAs include not only the major procyclic surface protein and enzymes of energy metabolism, but also protein kinases and stage-specific RNA-binding proteins: this suggests that alterations in RBP10 trigger a regulatory cascade.
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Christiano R, Kolev NG, Shi H, Ullu E, Walther TC, Tschudi C. The proteome and transcriptome of the infectious metacyclic form of Trypanosoma brucei define quiescent cells primed for mammalian invasion. Mol Microbiol 2017; 106:74-92. [PMID: 28742275 DOI: 10.1111/mmi.13754] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2017] [Indexed: 01/22/2023]
Abstract
The infectious metacyclic forms of Trypanosoma brucei result from a complex development in the tsetse fly vector. When they infect mammals, they cause African sleeping sickness in humans. Due to scarcity of biological material and difficulties of the tsetse fly as an experimental system, very limited information is available concerning the gene expression profile of metacyclic forms. We used an in vitro system based on expressing the RNA binding protein 6 to obtain infectious metacyclics and determined their protein and mRNA repertoires by mass-spectrometry (MS) based proteomics and mRNA sequencing (RNA-Seq) in comparison to non-infectious procyclic trypanosomes. We showed that metacyclics are quiescent cells, and propose this influences the choice of a monocistronic variant surface glycoprotein expression site. Metacyclics have a largely bloodstream-form type transcriptome, and thus are programmed to translate a bloodstream-form type proteome upon entry into the mammalian host and resumption of cell division. Genes encoding cell surface components showed the largest changes between procyclics and metacyclics, observed at both the transcript and protein levels. Genes encoding metabolic enzymes exhibited expression in metacyclics with features of both procyclic and bloodstream forms, suggesting that this intermediate-type metabolism is dictated by the availability of nutrients in the tsetse fly vector.
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Affiliation(s)
- Romain Christiano
- Department of Cell Biology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT 06520, USA
| | - Nikolay G Kolev
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT 06520, USA
| | - Huafang Shi
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT 06520, USA
| | - Elisabetta Ullu
- Department of Cell Biology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT 06520, USA.,Department of Internal Medicine, School of Medicine, Yale University, 330 Cedar St, Boardman 110, New Haven, CT 06520, USA
| | - Tobias C Walther
- Department of Cell Biology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT 06520, USA.,Howard Hughes Medical Institute, Harvard T.H. Chan School of Public Health Boston, MA 02115, USA
| | - Christian Tschudi
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT 06520, USA
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Mugo E, Egler F, Clayton C. Conversion of procyclic-form Trypanosoma brucei to the bloodstream form by transient expression of RBP10. Mol Biochem Parasitol 2017; 216:49-51. [PMID: 28651963 DOI: 10.1016/j.molbiopara.2017.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/22/2017] [Accepted: 06/23/2017] [Indexed: 12/22/2022]
Abstract
Bloodstream-form Trypanosoma brucei can lose the ability to differentiate to the procyclic form during prolonged in vitro culture. This can pose a problem during complicated genetic manipulation experiments, especially when the differentiation phenotype is under investigation. Ideally, to preserve differentiation competence, parasites should be cycled after every genetic manipulation step. Conversion of bloodstream-form Trypanosoma brucei to the procyclic form in vitro is routine, but conversion of procyclic forms to bloodstream forms has hitherto only been achieved in transgenic parasites with tetracycline-inducible expression of proteins with RNA-binding domains - either RBP6 or RBP10. This method, however, requires use of a selectable marker which might be needed for other purposes, and restricts options for tetracycline-inducible expression or repression of other genes. A simple method for inter-conversion that does not require permanent genetic manipulation would therefore be useful. Induced expression of RBP10 in procyclic forms gives faster differentiation than expression of RBP6, with a switch towards bloodstream forms within 48h. We here show that bloodstream forms can be obtained by transient transfection of procyclic forms with a circular plasmid designed for expression of RBP10 from an rRNA promoter. This method enables routine cycling of T. brucei without permanent genetic manipulation.
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Affiliation(s)
- Elisha Mugo
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D69120 Heidelberg, Germany
| | - Franziska Egler
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D69120 Heidelberg, Germany
| | - Christine Clayton
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D69120 Heidelberg, Germany.
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Hamidou Soumana I, Tchicaya B, Rialle S, Parrinello H, Geiger A. Comparative Genomics of Glossina palpalis gambiensis and G. morsitans morsitans to Reveal Gene Orthologs Involved in Infection by Trypanosoma brucei gambiense. Front Microbiol 2017; 8:540. [PMID: 28421044 PMCID: PMC5376623 DOI: 10.3389/fmicb.2017.00540] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/14/2017] [Indexed: 11/22/2022] Open
Abstract
Blood-feeding Glossina palpalis gambiense (Gpg) fly transmits the single-celled eukaryotic parasite Trypanosoma brucei gambiense (Tbg), the second Glossina fly African trypanosome pair being Glossina morsitans/T.brucei rhodesiense. Whatever the T. brucei subspecies, whereas the onset of their developmental program in the zoo-anthropophilic blood feeding flies does unfold in the fly midgut, its completion is taking place in the fly salivary gland where does emerge a low size metacyclic trypomastigote population displaying features that account for its establishment in mammals-human individuals included. Considering that the two Glossina—T. brucei pairs introduced above share similarity with respect to the developmental program of this African parasite, we were curious to map on the Glossina morsitans morsitans (Gmm), the Differentially Expressed Genes (DEGs) we listed in a previous study. Briefly, using the gut samples collected at days 3, 10, and 20 from Gpg that were fed or not at day 0 on Tbg—hosting mice, these DGE lists were obtained from RNA seq—based approaches. Here, post the mapping on the quality controlled DEGs on the Gmm genome, the identified ortholog genes were further annotated, the resulting datasets being compared. Around 50% of the Gpg DEGs were shown to have orthologs in the Gmm genome. Under one of the three Glossina midgut sampling conditions, the number of DEGs was even higher when mapping on the Gmm genome than initially recorded. Many Gmm genes annotated as “Hypothetical” were mapped and annotated on many distinct databases allowing some of them to be properly identified. We identify Glossina fly candidate genes encoding (a) a broad panel of proteases as well as (b) chitin—binding proteins, (c) antimicrobial peptide production—Pro3 protein, transferrin, mucin, atttacin, cecropin, etc—to further select in functional studies, the objectives being to probe and validated fly genome manipulation that prevents the onset of the developmental program of one or the other T. brucei spp. stumpy form sampled by one of the other bloodfeeding Glossina subspecies.
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Affiliation(s)
| | - Bernadette Tchicaya
- UMR 177, Institut de Recherche pour le Développement-CIRAD, CIRAD TA A-17/GMontpellier, France
| | - Stéphanie Rialle
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 5203, Institut de Génomique FonctionnelleMontpellier, France.,Institut National de la Santé Et de la Recherche Médicale U661Montpellier, France.,Universités de Montpellier 1 and 2, UMR 5203Montpellier, France.,Montpellier GenomiX, c/o Institut de Génomique FonctionnelleMontpellier, France
| | - Hugues Parrinello
- Centre National de la Recherche Scientifique Unité Mixte de Recherche 5203, Institut de Génomique FonctionnelleMontpellier, France.,Institut National de la Santé Et de la Recherche Médicale U661Montpellier, France.,Universités de Montpellier 1 and 2, UMR 5203Montpellier, France.,Montpellier GenomiX, c/o Institut de Génomique FonctionnelleMontpellier, France
| | - Anne Geiger
- UMR 177, Institut de Recherche pour le Développement-CIRAD, CIRAD TA A-17/GMontpellier, France
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