1
|
Coceres VM, Iriarte LS, Miranda-Magalhães A, Santos de Andrade TA, de Miguel N, Pereira-Neves A. Ultrastructural and Functional Analysis of a Novel Extra-Axonemal Structure in Parasitic Trichomonads. Front Cell Infect Microbiol 2021; 11:757185. [PMID: 34858875 PMCID: PMC8630684 DOI: 10.3389/fcimb.2021.757185] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/19/2021] [Indexed: 12/28/2022] Open
Abstract
Trichomonas vaginalis and Tritrichomonas foetus are extracellular flagellated parasites that inhabit humans and other mammals, respectively. In addition to motility, flagella act in a variety of biological processes in different cell types, and extra-axonemal structures (EASs) have been described as fibrillar structures that provide mechanical support and act as metabolic, homeostatic, and sensory platforms in many organisms. It has been assumed that T. vaginalis and T. foetus do not have EASs. However, here, we used complementary electron microscopy techniques to reveal the ultrastructure of EASs in both parasites. Such EASs are thin filaments (3-5 nm diameter) running longitudinally along the axonemes and surrounded by the flagellar membrane, forming prominent flagellar swellings. We observed that the formation of EAS increases after parasite adhesion on the host cells, fibronectin, and precationized surfaces. A high number of rosettes, clusters of intramembrane particles that have been proposed as sensorial structures, and microvesicles protruding from the membrane were observed in the EASs. Our observations demonstrate that T. vaginalis and T. foetus can connect to themselves by EASs present in flagella. The protein VPS32, a member of the ESCRT-III complex crucial for diverse membrane remodeling events, the pinching off and release of microvesicles, was found in the surface as well as in microvesicles protruding from EASs. Moreover, we demonstrated that the formation of EAS also increases in parasites overexpressing VPS32 and that T. vaginalis-VPS32 parasites showed greater motility in semisolid agar. These results provide valuable data about the role of the flagellar EASs in the cell-to-cell communication and pathogenesis of these extracellular parasites.
Collapse
Affiliation(s)
- Veronica M Coceres
- Laboratorio de Parásitos Anaerobios, Instituto Tecnológico Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas - Universidad Nacional de General San Martín (CONICET-UNSAM), Chascomús, Argentina
| | - Lucrecia S Iriarte
- Laboratorio de Parásitos Anaerobios, Instituto Tecnológico Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas - Universidad Nacional de General San Martín (CONICET-UNSAM), Chascomús, Argentina
| | | | | | - Natalia de Miguel
- Laboratorio de Parásitos Anaerobios, Instituto Tecnológico Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas y Técnicas - Universidad Nacional de General San Martín (CONICET-UNSAM), Chascomús, Argentina
| | | |
Collapse
|
2
|
Evaluation of the Immunoprotective Potential of Recombinant Paraflagellar Rod Proteins of Trypanosoma evansi in Mice. Vaccines (Basel) 2020; 8:vaccines8010084. [PMID: 32059486 PMCID: PMC7157580 DOI: 10.3390/vaccines8010084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 01/24/2020] [Accepted: 01/27/2020] [Indexed: 12/15/2022] Open
Abstract
Trypanosomosis, caused by Trypanosoma evansi, is an economically significant disease of livestock. Systematic antigenic variation by the parasite has undermined prospects for the development of a protective vaccine that targets the immunodominant surface antigens, encouraging exploration of alternatives. The paraflagellar rod (PFR), constituent proteins of the flagellum, are prominent non-variable vaccine candidates for T. evansi owing to their strategic location. Two major PFR constituent proteins, PFR1 (1770bp) and PFR2 (1800bp), were expressed using Escherichia coli. Swiss albino mice were immunized with the purified recombinant TePFR1 (89KDa) and TePFR2 (88KDa) proteins, as well as with the mix of the combined proteins at equimolar concentrations, and subsequently challenged with virulent T. evansi. The PFR-specific humoral response was assessed by ELISA. Cytometric bead-based assay was used to measure the cytokine response and flow cytometry for quantification of the cytokines. The recombinant TePFR proteins induced specific humoral responses in mice, including IgG1 followed by IgG2a and IgG2b. A balanced cytokine response induced by rTePFR 1 and 2 protein vaccination associated with extended survival and improved control of parasitemia following lethal challenge. The observation confirms the immunoprophylactic potential of the covert antigens of T. evansi.
Collapse
|
3
|
Krüger T, Schuster S, Engstler M. Beyond Blood: African Trypanosomes on the Move. Trends Parasitol 2018; 34:1056-1067. [DOI: 10.1016/j.pt.2018.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 08/01/2018] [Accepted: 08/03/2018] [Indexed: 01/07/2023]
|
4
|
Abstract
Trypanosoma brucei is a highly invasive pathogen capable of penetrating deeply into host tissues. To understand how flagellar motility facilitates cell penetration, we used cryo-electron tomography (cryo-ET) to visualize two genetically anucleate mutants with different flagellar motility behaviors. We found that the T. brucei cell body is highly deformable as defined by changes in cytoskeletal twist and spacing, in response to flagellar beating and environmental conditions. Based on the cryo-ET models, we proposed a mechanism of how flagellum motility is coupled to cell shape changes, which may facilitate penetration through size-limiting barriers. In the unicellular parasite Trypanosoma brucei, the causative agent of human African sleeping sickness, complex swimming behavior is driven by a flagellum laterally attached to the long and slender cell body. Using microfluidic assays, we demonstrated that T. brucei can penetrate through an orifice smaller than its maximum diameter. Efficient motility and penetration depend on active flagellar beating. To understand how active beating of the flagellum affects the cell body, we genetically engineered T. brucei to produce anucleate cytoplasts (zoids and minis) with different flagellar attachment configurations and different swimming behaviors. We used cryo-electron tomography (cryo-ET) to visualize zoids and minis vitrified in different motility states. We showed that flagellar wave patterns reflective of their motility states are coupled to cytoskeleton deformation. Based on these observations, we propose a mechanism for how flagellum beating can deform the cell body via a flexible connection between the flagellar axoneme and the cell body. This mechanism may be critical for T. brucei to disseminate in its host through size-limiting barriers.
Collapse
|
5
|
Maharana BR, Tewari AK, Singh V. An overview on kinetoplastid paraflagellar rod. J Parasit Dis 2015; 39:589-95. [PMID: 26688619 PMCID: PMC4675581 DOI: 10.1007/s12639-014-0422-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 01/13/2014] [Indexed: 01/23/2023] Open
Abstract
Kinetoplastids, the evolutionary ancient organisms exhibit a rich and diverse biology which epitomizes many of the fascinating topics of recent interest and study. These organisms possess a multifunctional organelle, the flagellum containing a canonical 9 + 2 axoneme which is involved in vital roles, viz. parasite cell division, morphogenesis, motility and immune evasion. Since Antony Van Leeuwenhoek's innovative explanation of 'little legs' helping the movements of microbes in 1975, this biological nanomachine has captured the thoughts of scientists. The core structure of kinetoplastid flagellum is embroidered with a range of extra-axonemal structures such as paraflagellar rod (PFR), a large lattice like structure which extends alongside the axoneme from the flagellar pocket to the flagellar tip. The coding sequences for significant components of PFR are highly conserved throughout the Kinetoplastida and Euglenida. The high order organization and restricted evolutionary distribution of the PFR components and structure makes the PFR a particularly valuable therapeutic and prophylactic target. This review focuses on the recent developments in identification of ultra structural components of PFR in order to understand the function of this intriguing organelle and devising strategies for therapeutic interventions.
Collapse
Affiliation(s)
- B. R. Maharana
- />Department of Veterinary Parasitology, College of Veterinary Science and Animal Husbandry, Junagadh Agricultural University, Junagadh, 362001 Gujarat India
| | - A. K. Tewari
- />Division of Veterinary Parasitology, Indian Veterinary Research Institute, Izatnagar, Bareilly, 243122 Uttar Pradesh India
| | - Veer Singh
- />Department of Veterinary Parasitology, College of Veterinary Science and Animal Husbandry, Sardar Krushinagar Dantiwada Agricultural University, Sardarkrushinagar, 3855006 Gujarat India
| |
Collapse
|
6
|
Kurup SP, Tarleton RL. The Trypanosoma cruzi flagellum is discarded via asymmetric cell division following invasion and provides early targets for protective CD8⁺ T cells. Cell Host Microbe 2015; 16:439-49. [PMID: 25299330 DOI: 10.1016/j.chom.2014.09.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 07/11/2014] [Accepted: 08/27/2014] [Indexed: 12/27/2022]
Abstract
During invasion of host cells by Trypanosoma cruzi, the parasite that causes Chagas disease, the elongated, flagellated trypomastigotes remodel into oval amastigotes with no external flagellum. The underlying mechanism of this remodeling and the fate of the flagellum are obscure. We discovered that T. cruzi trypomastigotes discard their flagella via an asymmetric cellular division. The flagellar proteins liberated become among the earliest parasite proteins to enter the MHC-I processing pathway in infected cells. Indeed, paraflagellar rod protein PAR4-specific CD8(+) T cells detect infected host cells >20 hr earlier than immunodominant trans-sialidase-specific T cells. Overexpression of PAR4 in T. cruzi enhanced the subdominant PAR4-specific CD8(+) T cell response, resulting in improved control of a challenge infection. These results provide insights into previously unappreciated events in intracellular invasion by T. cruzi and highlight the importance of T cells that recognize infected host cells early in the infectious process, in the control of infections.
Collapse
Affiliation(s)
- Samarchith P Kurup
- Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Rick L Tarleton
- Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA.
| |
Collapse
|
7
|
Generation of a nanobody targeting the paraflagellar rod protein of trypanosomes. PLoS One 2014; 9:e115893. [PMID: 25551637 PMCID: PMC4281110 DOI: 10.1371/journal.pone.0115893] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 11/27/2014] [Indexed: 11/23/2022] Open
Abstract
Trypanosomes are protozoan parasites that cause diseases in humans and livestock for which no vaccines are available. Disease eradication requires sensitive diagnostic tools and efficient treatment strategies. Immunodiagnostics based on antigen detection are preferable to antibody detection because the latter cannot differentiate between active infection and cure. Classical monoclonal antibodies are inaccessible to cryptic epitopes (based on their size-150 kDa), costly to produce and require cold chain maintenance, a condition that is difficult to achieve in trypanosomiasis endemic regions, which are mostly rural. Nanobodies are recombinant, heat-stable, small-sized (15 kDa), antigen-specific, single-domain, variable fragments derived from heavy chain-only antibodies in camelids. Because of numerous advantages over classical antibodies, we investigated the use of nanobodies for the targeting of trypanosome-specific antigens and diagnostic potential. An alpaca was immunized using lysates of Trypanosoma evansi. Using phage display and bio-panning techniques, a cross-reactive nanobody (Nb392) targeting all trypanosome species and isolates tested was selected. Imunoblotting, immunofluorescence microscopy, immunoprecipitation and mass spectrometry assays were combined to identify the target recognized. Nb392 targets paraflagellar rod protein (PFR1) of T. evansi, T. brucei, T. congolense and T. vivax. Two different RNAi mutants with defective PFR assembly (PFR2RNAi and KIF9BRNAi) were used to confirm its specificity. In conclusion, using a complex protein mixture for alpaca immunization, we generated a highly specific nanobody (Nb392) that targets a conserved trypanosome protein, i.e., PFR1 in the flagella of trypanosomes. Nb392 is an excellent marker for the PFR and can be useful in the diagnosis of trypanosomiasis. In addition, as demonstrated, Nb392 can be a useful research or PFR protein isolation tool.
Collapse
|
8
|
Brown RWB, Collingridge PW, Gull K, Rigden DJ, Ginger ML. Evidence for loss of a partial flagellar glycolytic pathway during trypanosomatid evolution. PLoS One 2014; 9:e103026. [PMID: 25050549 PMCID: PMC4106842 DOI: 10.1371/journal.pone.0103026] [Citation(s) in RCA: 5] [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: 05/30/2014] [Accepted: 06/27/2014] [Indexed: 11/18/2022] Open
Abstract
Classically viewed as a cytosolic pathway, glycolysis is increasingly recognized as a metabolic pathway exhibiting surprisingly wide-ranging variations in compartmentalization within eukaryotic cells. Trypanosomatid parasites provide an extreme view of glycolytic enzyme compartmentalization as several glycolytic enzymes are found exclusively in peroxisomes. Here, we characterize Trypanosoma brucei flagellar proteins resembling glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoglycerate kinase (PGK): we show the latter associates with the axoneme and the former is a novel paraflagellar rod component. The paraflagellar rod is an essential extra-axonemal structure in trypanosomes and related protists, providing a platform into which metabolic activities can be built. Yet, bioinformatics interrogation and structural modelling indicate neither the trypanosome PGK-like nor the GAPDH-like protein is catalytically active. Orthologs are present in a free-living ancestor of the trypanosomatids, Bodo saltans: the PGK-like protein from B. saltans also lacks key catalytic residues, but its GAPDH-like protein is predicted to be catalytically competent. We discuss the likelihood that the trypanosome GAPDH-like and PGK-like proteins constitute molecular evidence for evolutionary loss of a flagellar glycolytic pathway, either as a consequence of niche adaptation or the re-localization of glycolytic enzymes to peroxisomes and the extensive changes to glycolytic flux regulation that accompanied this re-localization. Evidence indicating loss of localized ATP provision via glycolytic enzymes therefore provides a novel contribution to an emerging theme of hidden diversity with respect to compartmentalization of the ubiquitous glycolytic pathway in eukaryotes. A possibility that trypanosome GAPDH-like protein additionally represents a degenerate example of a moonlighting protein is also discussed.
Collapse
Affiliation(s)
- Robert W. B. Brown
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom
| | | | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Daniel J. Rigden
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Michael L. Ginger
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom
- * E-mail:
| |
Collapse
|
9
|
Singh K, Veluru NK, Trivedi V, Gupta CM, Sahasrabuddhe AA. An actin-like protein is involved in regulation of mitochondrial and flagellar functions as well as in intramacrophage survival of Leishmania donovani. Mol Microbiol 2014; 91:562-78. [PMID: 24354789 DOI: 10.1111/mmi.12477] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2013] [Indexed: 11/30/2022]
Abstract
Actin-related proteins are ubiquitous actin-like proteins that show high similarity with actin in terms of their amino acid sequence and three-dimensional structure. However, in lower eukaryotes, such as trypanosomatids, their functions have not yet been explored. Here, we show that a novel actin-related protein (ORF LmjF.13.0950) is localized mainly in the Leishmania mitochondrion. We further reveal that depletion of the intracellular levels of this protein leads to an appreciable decrease in the mitochondrial membrane potential as well as in the ATP production, which appears to be accompanied with impairment in the flagellum assembly and motility. Additionally, we report that the mutants so generated fail to survive inside the mouse peritoneal macrophages. These abnormalities are, however, reversed by the episomal gene complementation. Our results, for the first time indicate that apart from their classical roles in the cytoplasm and nucleus, actin-related proteins may also regulate the mitochondrial function, and in case of Leishmania donovani they may also serve as the essential factor for their survival in the host cells.
Collapse
Affiliation(s)
- Kuldeep Singh
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, PIN-226031, Uttar Pradesh, India
| | | | | | | | | |
Collapse
|
10
|
Morga B, Bastin P. Getting to the heart of intraflagellar transport using Trypanosoma and Chlamydomonas models: the strength is in their differences. Cilia 2013; 2:16. [PMID: 24289478 PMCID: PMC4015504 DOI: 10.1186/2046-2530-2-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/11/2013] [Indexed: 11/22/2022] Open
Abstract
Cilia and flagella perform diverse roles in motility and sensory perception, and defects in their construction or their function are responsible for human genetic diseases termed ciliopathies. Cilia and flagella construction relies on intraflagellar transport (IFT), the bi-directional movement of ‘trains’ composed of protein complexes found between axoneme microtubules and the flagellum membrane. Although extensive information about IFT components and their mode of action were discovered in the green algae Chlamydomonas reinhardtii, other model organisms have revealed further insights about IFT. This is the case of Trypanosoma brucei, a flagellated protist responsible for sleeping sickness that is turning out to be an emerging model for studying IFT. In this article, we review different aspects of IFT, based on studies of Chlamydomonas and Trypanosoma. Data available from both models are examined to ask challenging questions about IFT such as the initiation of flagellum construction, the setting-up of IFT and the mode of formation of IFT trains, and their remodeling at the tip as well as their recycling at the base. Another outstanding question is the individual role played by the multiple IFT proteins. The use of different models, bringing their specific biological and experimental advantages, will be invaluable in order to obtain a global understanding of IFT.
Collapse
Affiliation(s)
- Benjamin Morga
- Trypanosome Cell Biology Unit, Institut Pasteur and CNRS, URA 2581, 25 rue du Docteur Roux, 75015, Paris, France.
| | | |
Collapse
|
11
|
Diniz MC, Pacheco ACL, Farias KM, de Oliveira DM. The eukaryotic flagellum makes the day: novel and unforeseen roles uncovered after post-genomics and proteomics data. Curr Protein Pept Sci 2013; 13:524-46. [PMID: 22708495 PMCID: PMC3499766 DOI: 10.2174/138920312803582951] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 05/22/2012] [Accepted: 05/23/2012] [Indexed: 12/21/2022]
Abstract
This review will summarize and discuss the current biological understanding of the motile eukaryotic flagellum,
as posed out by recent advances enabled by post-genomics and proteomics approaches. The organelle, which is crucial
for motility, survival, differentiation, reproduction, division and feeding, among other activities, of many eukaryotes,
is a great example of a natural nanomachine assembled mostly by proteins (around 350-650 of them) that have been conserved
throughout eukaryotic evolution. Flagellar proteins are discussed in terms of their arrangement on to the axoneme,
the canonical “9+2” microtubule pattern, and also motor and sensorial elements that have been detected by recent proteomic
analyses in organisms such as Chlamydomonas reinhardtii, sea urchin, and trypanosomatids. Such findings can be
remarkably matched up to important discoveries in vertebrate and mammalian types as diverse as sperm cells, ciliated
kidney epithelia, respiratory and oviductal cilia, and neuro-epithelia, among others. Here we will focus on some exciting
work regarding eukaryotic flagellar proteins, particularly using the flagellar proteome of C. reinhardtii as a reference map
for exploring motility in function, dysfunction and pathogenic flagellates. The reference map for the eukaryotic flagellar
proteome consists of 652 proteins that include known structural and intraflagellar transport (IFT) proteins, less well-characterized
signal transduction proteins and flagellar associated proteins (FAPs), besides almost two hundred unannotated
conserved proteins, which lately have been the subject of intense investigation and of our present examination.
Collapse
Affiliation(s)
- Michely C Diniz
- Programa de Pós-Graduação em Biotecnologia-RENORBIO-Rede Nordeste de Biotecnologia, Universidade Estadual do Ceará-UECE, Av. Paranjana, 1700, Campus do Itaperi, Fortaleza, CE 60740-000 Brasil
| | | | | | | |
Collapse
|
12
|
Ginger ML, Collingridge PW, Brown RWB, Sproat R, Shaw MK, Gull K. Calmodulin is required for paraflagellar rod assembly and flagellum-cell body attachment in trypanosomes. Protist 2013; 164:528-40. [PMID: 23787017 DOI: 10.1016/j.protis.2013.05.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2012] [Revised: 05/03/2013] [Accepted: 05/09/2013] [Indexed: 02/02/2023]
Abstract
In the flagellum of the African sleeping sickness parasite Trypanosoma brucei calmodulin (CaM) is found within the paraflagellar rod (PFR), an elaborate extra-axonemal structure, and the axoneme. In dissecting mechanisms of motility regulation we analysed CaM function using RNAi. Unexpectedly CaM depletion resulted in total and catastrophic failure in PFR assembly; even connections linking axoneme to PFR failed to form following CaM depletion. This provides an intriguing parallel with the role in the green alga Chlamydomonas of a CaM-related protein in docking outer-dynein arms to axoneme outer-doublet microtubules. Absence of CaM had no discernible effect on axoneme assembly, but the failure in PFR assembly was further compounded by loss of the normal linkage between PFR and axoneme to the flagellum attachment zone of the cell body. Thus, flagellum detachment was a secondary, time-dependent consequence of CaM RNAi, and coincided with the loss of normal trypomastigote morphology, thereby linking the presence of PFR architecture with maintenance of cell form, as well as cell motility. Finally, wider comparison between the flagellum detachment phenotypes of RNAi mutants for CaM and the FLA1 glycoprotein potentially provides new perspective into the function of the latter into establishing and maintaining flagellum-cell body attachment.
Collapse
Affiliation(s)
- Michael L Ginger
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK.
| | | | | | | | | | | |
Collapse
|
13
|
Abstract
Eukaryotic cilia/flagella are ancient organelles with motility and sensory functions. Cilia display significant ultrastructural conservation where present across the eukaryotic phylogeny; however, diversity in ciliary biology exists and the ability to produce cilia has been lost independently on a number of occasions. Land plants provide an excellent system for the investigation of cilia evolution and loss across a broad phylogeny, because early divergent land plant lineages produce cilia, whereas most seed plants do not. This review highlights the differences in cilia form and function across land plants and discusses how recent advances in genomics are providing novel insights into the evolutionary trajectory of ciliary proteins. We propose a renewed effort to adopt ciliated land plants as models to investigate the mechanisms underpinning complex ciliary processes, such as number control, the coordination of basal body placement and the regulation of beat patterns.
Collapse
Affiliation(s)
- Matthew E Hodges
- Department of Plant Sciences, South Parks Road, University of Oxford, Oxford OX1 3RB, UK
| | - Bill Wickstead
- Centre for Genetics and Genomics, University of Nottingham, Nottingham NG7 2UH, UK
| | - Keith Gull
- Sir William Dunn School of Pathology, South Parks Road, University of Oxford, Oxford OX1 3RE, UK
| | - Jane A Langdale
- Department of Plant Sciences, South Parks Road, University of Oxford, Oxford OX1 3RB, UK
| |
Collapse
|
14
|
Abstract
Trypanosoma brucei is the etiological agent of devastating parasitic disease in humans and livestock in sub-saharan Africa. The pathogenicity and growth of the parasite are intimately linked to its shape and form. This is in turn derived from a highly ordered microtubule cytoskeleton that forms a tightly arrayed cage directly beneath the pellicular membrane and numerous other cytoskeletal structures such as the flagellum. The parasite undergoes extreme changes in cellular morphology during its life cycle and cell cycles which require a high level of integration and coordination of cytoskeletal processes. In this review we will discuss the role that proteomics techniques have had in advancing our understanding of the molecular composition of the cytoskeleton and its functions. We then consider future opportunities for the application of these techniques in terms of addressing some of the unanswered questions of trypanosome cytoskeletal cell biology with particular focus on the differences in the composition and organisation of the cytoskeleton through the trypanosome life-cycle.
Collapse
|
15
|
Dacheux D, Landrein N, Thonnus M, Gilbert G, Sahin A, Wodrich H, Robinson DR, Bonhivers M. A MAP6-related protein is present in protozoa and is involved in flagellum motility. PLoS One 2012; 7:e31344. [PMID: 22355359 PMCID: PMC3280300 DOI: 10.1371/journal.pone.0031344] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 01/06/2012] [Indexed: 12/25/2022] Open
Abstract
In vertebrates the microtubule-associated proteins MAP6 and MAP6d1 stabilize cold-resistant microtubules. Cilia and flagella have cold-stable microtubules but MAP6 proteins have not been identified in these organelles. Here, we describe TbSAXO as the first MAP6-related protein to be identified in a protozoan, Trypanosoma brucei. Using a heterologous expression system, we show that TbSAXO is a microtubule stabilizing protein. Furthermore we identify the domains of the protein responsible for microtubule binding and stabilizing and show that they share homologies with the microtubule-stabilizing Mn domains of the MAP6 proteins. We demonstrate, in the flagellated parasite, that TbSAXO is an axonemal protein that plays a role in flagellum motility. Lastly we provide evidence that TbSAXO belongs to a group of MAP6-related proteins (SAXO proteins) present only in ciliated or flagellated organisms ranging from protozoa to mammals. We discuss the potential roles of the SAXO proteins in cilia and flagella function.
Collapse
Affiliation(s)
- Denis Dacheux
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, Institut Polytechnique de Bordeaux, UMR 5234, Bordeaux, France
| | - Nicolas Landrein
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
| | - Magali Thonnus
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
| | - Guillaume Gilbert
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
| | - Annelise Sahin
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
| | - Harald Wodrich
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
| | - Derrick R. Robinson
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
| | - Mélanie Bonhivers
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
- * E-mail:
| |
Collapse
|
16
|
Lye LF, Owens K, Shi H, Murta SMF, Vieira AC, Turco SJ, Tschudi C, Ullu E, Beverley SM. Retention and loss of RNA interference pathways in trypanosomatid protozoans. PLoS Pathog 2010; 6:e1001161. [PMID: 21060810 PMCID: PMC2965760 DOI: 10.1371/journal.ppat.1001161] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 09/23/2010] [Indexed: 01/02/2023] Open
Abstract
RNA interference (RNAi) pathways are widespread in metaozoans but the genes required show variable occurrence or activity in eukaryotic microbes, including many pathogens. While some Leishmania lack RNAi activity and Argonaute or Dicer genes, we show that Leishmania braziliensis and other species within the Leishmania subgenus Viannia elaborate active RNAi machinery. Strong attenuation of expression from a variety of reporter and endogenous genes was seen. As expected, RNAi knockdowns of the sole Argonaute gene implicated this protein in RNAi. The potential for functional genetics was established by testing RNAi knockdown lines lacking the paraflagellar rod, a key component of the parasite flagellum. This sets the stage for the systematic manipulation of gene expression through RNAi in these predominantly diploid asexual organisms, and may also allow selective RNAi-based chemotherapy. Functional evolutionary surveys of RNAi genes established that RNAi activity was lost after the separation of the Leishmania subgenus Viannia from the remaining Leishmania species, a divergence associated with profound changes in the parasite infectious cycle and virulence. The genus Leishmania therefore offers an accessible system for testing hypothesis about forces that may select for the loss of RNAi during evolution, such as invasion by viruses, changes in genome plasticity mediated by transposable elements and gene amplification (including those mediating drug resistance), and/or alterations in parasite virulence. RNAi interference pathways play fundamental roles in eukaryotes and provide important methods for the analysis of gene function. Occasionally RNAi has been lost, precluding its use as a tool, as well as raising the question of what forces could lead to loss of such a key pathway. Genomic and functional studies previously showed that within trypanosomatids protozoans RNAi was absent in both Leishmania major and Trypanosoma cruzi. The genome of L. braziliensis, a member of the early diverging Leishmania subgenus Viannia, retained key genes required for RNAi such as an Argonaute. We demonstrated that in fact L. braziliensis shows strong RNAi activity with reporter and endogenous genes affecting flagellar function. These data suggest that RNAi may be productively applied for functional genomic studies in L. braziliensis. We mapped the evolutionary point at which RNAi was lost in lineage leading to Leishmania and Crithidia, and establish that RNAi must have been lost at least twice in the trypanosomatids, once on the lineage leading to T. cruzi and independently following the divergence of the Viannia subgenus from other Leishmania species. Lastly, we discuss hypotheses concerning the forces leading to the loss of RNAi in Leishmania evolution, including viral invasion, increased genome plasticity, and altered virulence.
Collapse
Affiliation(s)
- Lon-Fye Lye
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Katherine Owens
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Huafang Shi
- Department of Internal Medicine, Yale University Medical School, New Haven, Connecticut, United States of America
| | - Silvane M. F. Murta
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Ana Carolina Vieira
- Department of Biochemistry, University of Kentucky Medical Center, Lexington, Kentucky, United States of America
| | - Salvatore J. Turco
- Department of Biochemistry, University of Kentucky Medical Center, Lexington, Kentucky, United States of America
| | - Christian Tschudi
- Department of Internal Medicine, Yale University Medical School, New Haven, Connecticut, United States of America
- Department of Epidemiology & Public Health, Yale University Medical School, New Haven, Connecticut, United States of America
| | - Elisabetta Ullu
- Department of Internal Medicine, Yale University Medical School, New Haven, Connecticut, United States of America
- Department of Cell Biology, Yale University Medical School, New Haven, Connecticut, United States of America
| | - Stephen M. Beverley
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
| |
Collapse
|
17
|
Chan KY, Ersfeld K. The role of the Kinesin-13 family protein TbKif13-2 in flagellar length control of Trypanosoma brucei. Mol Biochem Parasitol 2010; 174:137-40. [PMID: 20728476 PMCID: PMC2984613 DOI: 10.1016/j.molbiopara.2010.08.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 07/27/2010] [Accepted: 08/11/2010] [Indexed: 11/30/2022]
Abstract
TbKif13-2, a member of the microtubule-depolymerising Kinesin-13 family was localised at the tip of the flagellum in Trypanosoma brucei. Its predicted activity suggested a role in the regulation of axonemal length. However, using gene deletion and overexpression of TbKif13-2 we show that, in procyclic T. brucei, this kinesin has only a very limited effect on flagellar length. Gene deletion resulted in no significant elongation of the flagellum and overexpression only slightly decreased flagellar length and the rate of growth of a new flagellum during cell division. This is in contrast to studies in Leishmania major, where overexpression of the TbKif13-2 homologue resulted in a significant length reduction of the flagellum. Knockout of TbKif13-2 has, however, an effect on the initial growth of the emerging new flagellum. In conclusion, we show that TbKif13-2 has only a marginal impact on flagellar length in T. brucei.
Collapse
Affiliation(s)
- Kuan Yoow Chan
- Department of Biological Sciences, University of Hull, Hull, UK
| | | |
Collapse
|
18
|
Katta SS, Tammana TVS, Sahasrabuddhe AA, Bajpai VK, Gupta CM. Trafficking activity of myosin XXI is required in assembly of Leishmania flagellum. J Cell Sci 2010; 123:2035-44. [PMID: 20501700 DOI: 10.1242/jcs.064725] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Actin-based myosin motors have a pivotal role in intracellular trafficking in eukaryotic cells. The parasitic protozoan organism Leishmania expresses a novel class of myosin, myosin XXI (Myo21), which is preferentially localized at the proximal region of the flagellum. However, its function in this organism remains largely unknown. Here, we show that Myo21 interacts with actin, and its expression is dependent of the growth stage. We further reveal that depletion of Myo21 levels results in impairment of the flagellar assembly and intracellular trafficking. These defects are, however, reversed by episomal complementation. Additionally, it is shown that deletion of the Myo21 gene leads to generation of ploidy, suggesting an essential role of Myo21 in survival of Leishmania cells. Together, these results indicate that actin-dependent trafficking activity of Myo21 is essentially required during assembly of the Leishmania flagellum.
Collapse
Affiliation(s)
- Santharam S Katta
- Molecular and Structural Biology Division, Central Drug Research Institute, CSIR, Uttar Pradesh, Lucknow, India
| | | | | | | | | |
Collapse
|
19
|
Harder S, Thiel M, Clos J, Bruchhaus I. Characterization of a subunit of the outer dynein arm docking complex necessary for correct flagellar assembly in Leishmania donovani. PLoS Negl Trop Dis 2010; 4:e586. [PMID: 20126266 PMCID: PMC2811169 DOI: 10.1371/journal.pntd.0000586] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 12/07/2009] [Indexed: 11/18/2022] Open
Abstract
Background In order to proceed through their life cycle, Leishmania parasites switch between sandflies and mammals. The flagellated promastigote cells transmitted by the insect vector are phagocytized by macrophages within the mammalian host and convert into the amastigote stage, which possesses a rudimentary flagellum only. During an earlier proteomic study of the stage differentiation of the parasite we identified a component of the outer dynein arm docking complex, a structure of the flagellar axoneme. The 70 kDa subunit of the outer dynein arm docking complex consists of three subunits altogether and is essential for the assembly of the outer dynein arm onto the doublet microtubule of the flagella. According to the nomenclature of the well-studied Chlamydomonas reinhardtii complex we named the Leishmania protein LdDC2. Methodology/Principal Findings This study features a characterization of the protein over the life cycle of the parasite. It is synthesized exclusively in the promastigote stage and localizes to the flagellum. Gene replacement mutants of lddc2 show reduced growth rates and diminished flagellar length. Additionally, the normally spindle-shaped promastigote parasites reveal a more spherical cell shape giving them an amastigote-like appearance. The mutants lose their motility and wiggle in place. Ultrastructural analyses reveal that the outer dynein arm is missing. Furthermore, expression of the amastigote-specific A2 gene family was detected in the deletion mutants in the absence of a stage conversion stimulus. In vitro infectivity is slightly increased in the mutant cell line compared to wild-type Leishmania donovani parasites. Conclusions/Significance Our results indicate that the correct assembly of the flagellum has a great influence on the investigated characteristics of Leishmania parasites. The lack of a single flagellar protein causes an aberrant morphology, impaired growth and altered infectiousness of the parasite. Leishmania parasites are responsible for the disease leishmaniasis. They are spread through sandflies. The primary hosts are mammals, including humans. They occur in two different morphological forms. The flagellated promastigotes live in the gut of the sandfly vector. After transmission to the mammalian host they get phagocytized by macrophages and convert into the amastigote form, which is able to survive within the phagolysosome. The molecular mechanisms underlying this transformation process from promastigote to amastigote are poorly understood so far. A striking difference of the life cycle stages is a long flagellum in the promastigote compared to only a rudimentary flagellum in the mammalian stage amastigote. During an earlier study of the stage differentiation of Leishmania donovani we identified a flagellar protein, a subunit of the outer dynein arm docking complex (ODA-DC2). This protein is part of a flagellar structure called the axoneme. Here we have further characterized the protein regarding its role within the life cycle of the parasite. Mutant promastigotes lacking DC2 protein show reduced flagellar length and a more amastigote-like appearance overall. In addition, the motility is heavily retrenched and transmission electron microscopy indicated that the flagellar ultrastructure is affected. Furthermore, the mutants express amastigote-specific genes and show increased in vitro infectiousness towards macrophages. Therefore, we conclude that the correct assembly of the flagellum is vital for maintenance of the promastigote stage of the parasite.
Collapse
Affiliation(s)
- Simone Harder
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
| | | | | | | |
Collapse
|
20
|
|
21
|
A protein-protein interaction map of the Trypanosoma brucei paraflagellar rod. PLoS One 2009; 4:e7685. [PMID: 19888464 PMCID: PMC2766642 DOI: 10.1371/journal.pone.0007685] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 10/12/2009] [Indexed: 11/19/2022] Open
Abstract
We have conducted a protein interaction study of components within a specific sub-compartment of a eukaryotic flagellum. The trypanosome flagellum contains a para-crystalline extra-axonemal structure termed the paraflagellar rod (PFR) with around forty identified components. We have used a Gateway cloning approach coupled with yeast two-hybrid, RNAi and 2D DiGE to define a protein-protein interaction network taking place in this structure. We define two clusters of interactions; the first being characterised by two proteins with a shared domain which is not sufficient for maintaining the interaction. The other cohort is populated by eight proteins, a number of which possess a PFR domain and sub-populations of this network exhibit dependency relationships. Finally, we provide clues as to the structural organisation of the PFR at the molecular level. This multi-strand approach shows that protein interactome data can be generated for insoluble protein complexes.
Collapse
|
22
|
Portman N, Gull K. The paraflagellar rod of kinetoplastid parasites: from structure to components and function. Int J Parasitol 2009; 40:135-48. [PMID: 19879876 PMCID: PMC2813431 DOI: 10.1016/j.ijpara.2009.10.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 10/13/2009] [Accepted: 10/16/2009] [Indexed: 01/06/2023]
Abstract
The role of the eukaryotic flagellum in cell motility is well established but its importance in many other aspects of cell biology, from cell signalling to developmental regulation, is becoming increasingly apparent. In addition to this diversity of function the core structure of the flagellum, which has been inherited from the earliest ancestor of all eukaryotes, is embellished with a range of extra-axonemal structures in many organisms. One of the best studied of these structures is the paraflagellar rod of kinetoplastid protozoa in which the morphological characteristics have been well defined and some of the major protein constituents have been identified. Here we discuss recent advances in the identification of further molecular components of the paraflagellar rod, how these impact on our understanding of its function and regulation and the implications for therapeutic intervention in a number of devastating human pathologies.
Collapse
Affiliation(s)
- Neil Portman
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX13RE, UK
| | | |
Collapse
|
23
|
Portman N, Lacomble S, Thomas B, McKean PG, Gull K. Combining RNA interference mutants and comparative proteomics to identify protein components and dependences in a eukaryotic flagellum. J Biol Chem 2009; 284:5610-9. [PMID: 19074134 PMCID: PMC2645819 DOI: 10.1074/jbc.m808859200] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Indexed: 01/23/2023] Open
Abstract
Eukaryotic flagella from organisms such as Trypanosoma brucei can be isolated and their protein components identified by mass spectrometry. Here we used a comparative approach utilizing two-dimensional difference gel electrophoresis and isobaric tags for relative and absolute quantitation to reveal protein components of flagellar structures via ablation by inducible RNA interference mutation. By this approach we identified 20 novel components of the paraflagellar rod (PFR). Using epitope tagging we validated a subset of these as being present within the PFR by immunofluorescence. Bioinformatic analysis of the PFR cohort reveals a likely calcium/calmodulin regulatory/signaling linkage between some components. We extended the RNA interference mutant/comparative proteomic analysis to individual novel components of our PFR proteome, showing that the approach has the power to reveal dependences between subgroups within the cohort.
Collapse
MESH Headings
- Animals
- Cells, Cultured
- Chromatography, Liquid
- DNA, Protozoan/genetics
- DNA, Protozoan/metabolism
- Electrophoresis, Gel, Two-Dimensional
- Flagella/genetics
- Flagella/metabolism
- Fluorescent Antibody Technique
- Proteomics
- Protozoan Proteins/antagonists & inhibitors
- Protozoan Proteins/genetics
- Protozoan Proteins/metabolism
- RNA Interference
- RNA, Protozoan/genetics
- RNA, Protozoan/metabolism
- RNA, Small Interfering/pharmacology
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Trypanosoma brucei brucei/genetics
- Trypanosoma brucei brucei/metabolism
Collapse
Affiliation(s)
- Neil Portman
- Sir William Dunn School of Pathology and Oxford Centre for Integrative Systems Biology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom
| | | | | | | | | |
Collapse
|
24
|
Abstract
In unicellular and multicellular eukaryotes, fast cell motility and rapid movement of material over cell surfaces are often mediated by ciliary or flagellar beating. The conserved defining structure in most motile cilia and flagella is the '9+2' microtubule axoneme. Our general understanding of flagellum assembly and the regulation of flagellar motility has been led by results from seminal studies of flagellate protozoa and algae. Here we review recent work relating to various aspects of protist physiology and cell biology. In particular, we discuss energy metabolism in eukaryotic flagella, modifications to the canonical assembly pathway and flagellum function in parasite virulence.
Collapse
|
25
|
Absalon S, Blisnick T, Bonhivers M, Kohl L, Cayet N, Toutirais G, Buisson J, Robinson D, Bastin P. Flagellum elongation is required for correct structure, orientation and function of the flagellar pocket in Trypanosoma brucei. J Cell Sci 2008; 121:3704-16. [PMID: 18940910 DOI: 10.1242/jcs.035626] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In trypanosomes, the flagellum is rooted in the flagellar pocket, a surface micro-domain that is the sole site for endocytosis and exocytosis. By analysis of anterograde or retrograde intraflagellar transport in IFT88RNAi or IFT140RNAi mutant cells, we show that elongation of the new flagellum is not required for flagellar pocket formation but is essential for its organisation, orientation and function. Transmission electron microscopy revealed that the flagellar pocket exhibited a modified shape (smaller, distorted and/or deeper) in cells with abnormally short or no flagella. Scanning electron microscopy analysis of intact and detergent-extracted cells demonstrated that the orientation of the flagellar pocket collar was more variable in trypanosomes with short flagella. The structural protein BILBO1 was present but its localisation and abundance was altered. The membrane flagellar pocket protein CRAM leaked out of the pocket and reached the short flagella. CRAM also accumulated in intracellular compartments, indicating defects in routing of resident flagellar pocket proteins. Perturbations of vesicular trafficking were obvious; vesicles were observed in the lumen of the flagellar pocket or in the short flagella, and fluid-phase endocytosis was drastically diminished in non-flagellated cells. We propose a model to explain the role of flagellum elongation in correct flagellar pocket organisation and function.
Collapse
Affiliation(s)
- Sabrina Absalon
- Trypanosome Cell Biology Unit, Pasteur Institute and CNRS, 25 rue du Docteur Roux, 75015 Paris, France
| | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Tammana TVS, Sahasrabuddhe AA, Mitra K, Bajpai VK, Gupta CM. Actin-depolymerizing factor, ADF/cofilin, is essentially required in assembly of Leishmania flagellum. Mol Microbiol 2008; 70:837-52. [PMID: 18793337 DOI: 10.1111/j.1365-2958.2008.06448.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
ADF/cofilins are ubiquitous actin dynamics-regulating proteins that have been mainly implicated in actin-based cell motility. Trypanosomatids, e.g. Leishmania and Trypanosoma, which mediate their motility through flagellum, also contain a putative ADF/cofilin homologue, but its role in flagellar motility remains largely unexplored. We have investigated the role of this protein in assembly and motility of the Leishmania flagellum after knocking out the ADF/cofilin gene by targeted gene replacement. The resultant mutants were completely immotile, short and stumpy, and had reduced flagellar length and severely impaired beat. In addition, the assembly of the paraflagellar rod was lost, vesicle-like structures were seen throughout the length of the flagellum and the state and distribution of actin were altered. However, episomal complementation of the gene restored normal morphology and flagellar function. These results for the first time indicate that the actin dynamics-regulating protein ADF/cofilin plays a critical role in assembly and motility of the eukaryotic flagellum.
Collapse
Affiliation(s)
- T V Satish Tammana
- Division of Molecular and Structural Biology, Central Drug Research Institute, Lucknow 226001, India
| | | | | | | | | |
Collapse
|
27
|
Absalon S, Blisnick T, Kohl L, Toutirais G, Doré G, Julkowska D, Tavenet A, Bastin P. Intraflagellar transport and functional analysis of genes required for flagellum formation in trypanosomes. Mol Biol Cell 2007; 19:929-44. [PMID: 18094047 DOI: 10.1091/mbc.e07-08-0749] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Intraflagellar transport (IFT) is the bidirectional movement of protein complexes required for cilia and flagella formation. We investigated IFT by analyzing nine conventional IFT genes and five novel putative IFT genes (PIFT) in Trypanosoma brucei that maintain its existing flagellum while assembling a new flagellum. Immunostaining against IFT172 or expression of tagged IFT20 or green fluorescent protein GFP::IFT52 revealed the presence of IFT proteins along the axoneme and at the basal body and probasal body regions of both old and new flagella. IFT particles were detected by electron microscopy and exhibited a strict localization to axonemal microtubules 3-4 and 7-8, suggesting the existence of specific IFT tracks. Rapid (>3 microm/s) bidirectional intraflagellar movement of GFP::IFT52 was observed in old and new flagella. RNA interference silencing demonstrated that all individual IFT and PIFT genes are essential for new flagellum construction but the old flagellum remained present. Inhibition of IFTB proteins completely blocked axoneme construction. Absence of IFTA proteins (IFT122 and IFT140) led to formation of short flagella filled with IFT172, indicative of defects in retrograde transport. Two PIFT proteins turned out to be required for retrograde transport and three for anterograde transport. Finally, flagellum membrane elongation continues despite the absence of axonemal microtubules in all IFT/PIFT mutant.
Collapse
Affiliation(s)
- Sabrina Absalon
- Trypanosome Cell Biology Unit, Pasteur Institute and Centre National de la Recherche Scientifique, 75015 Paris, France
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Stephan A, Vaughan S, Shaw MK, Gull K, McKean PG. An essential quality control mechanism at the eukaryotic basal body prior to intraflagellar transport. Traffic 2007; 8:1323-30. [PMID: 17645436 DOI: 10.1111/j.1600-0854.2007.00611.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Constructing a eukaryotic cilium/flagellum is a demanding task requiring the transport of proteins from their cytoplasmic synthesis site into a spatially and environmentally distinct cellular compartment. The clear potential hazard is that import of aberrant proteins could seriously disable cilia/flagella assembly or turnover processes. Here, we reveal that tubulin protein destined for incorporation into axonemal microtubules interacts with a tubulin cofactor C (TBCC) domain-containing protein that is specifically located at the mature basal body transitional fibres. RNA interference-mediated ablation of this protein results in axonemal microtubule defects but no effect on other microtubule populations within the cell. Bioinformatics analysis indicates that this protein belongs to a clade of flagellum-specific TBCC-like proteins that includes the human protein, XRP2, mutations which lead to certain forms of the hereditary eye disease retinitis pigmentosa. Taken with other observations regarding the role of transitional fibres in cilium/flagellum assembly, we suggest that a localized protein processing capacity embedded at transitional fibres ensures the 'quality' of tubulin imported into the cilium/flagellum, and further, that loss of a ciliary/flagellar quality control capability may underpin a number of human genetic disorders.
Collapse
Affiliation(s)
- Angela Stephan
- Biomedical Sciences Unit, Department of Biological Sciences, Lancaster University, Lancaster, LA1 4YQ, UK
| | | | | | | | | |
Collapse
|
29
|
Absalon S, Kohl L, Branche C, Blisnick T, Toutirais G, Rusconi F, Cosson J, Bonhivers M, Robinson D, Bastin P. Basal body positioning is controlled by flagellum formation in Trypanosoma brucei. PLoS One 2007; 2:e437. [PMID: 17487282 PMCID: PMC1857822 DOI: 10.1371/journal.pone.0000437] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Accepted: 04/09/2007] [Indexed: 11/18/2022] Open
Abstract
To perform their multiple functions, cilia and flagella are precisely positioned at the cell surface by mechanisms that remain poorly understood. The protist Trypanosoma brucei possesses a single flagellum that adheres to the cell body where a specific cytoskeletal structure is localised, the flagellum attachment zone (FAZ). Trypanosomes build a new flagellum whose distal tip is connected to the side of the old flagellum by a discrete structure, the flagella connector. During this process, the basal body of the new flagellum migrates towards the posterior end of the cell. We show that separate inhibition of flagellum assembly, base-to-tip motility or flagella connection leads to reduced basal body migration, demonstrating that the flagellum contributes to its own positioning. We propose a model where pressure applied by movements of the growing new flagellum on the flagella connector leads to a reacting force that in turn contributes to migration of the basal body at the proximal end of the flagellum.
Collapse
Affiliation(s)
- Sabrina Absalon
- Dynamique et Régulation des Génomes, Muséum National d'Histoire Naturelle, INSERM and CNRS, Paris, France
- Trypanosome Cell Biology Unit, Pasteur Institute and CNRS, Paris, France
| | - Linda Kohl
- Dynamique et Régulation des Génomes, Muséum National d'Histoire Naturelle, INSERM and CNRS, Paris, France
- Biologie Fonctionnelle des Protozoaires, Muséum National d'Histoire Naturelle, Paris, France
| | - Carole Branche
- Dynamique et Régulation des Génomes, Muséum National d'Histoire Naturelle, INSERM and CNRS, Paris, France
- Trypanosome Cell Biology Unit, Pasteur Institute and CNRS, Paris, France
| | - Thierry Blisnick
- Trypanosome Cell Biology Unit, Pasteur Institute and CNRS, Paris, France
| | - Géraldine Toutirais
- Dynamique et Régulation des Génomes, Muséum National d'Histoire Naturelle, INSERM and CNRS, Paris, France
| | - Filippo Rusconi
- Dynamique et Régulation des Génomes, Muséum National d'Histoire Naturelle, INSERM and CNRS, Paris, France
| | - Jacky Cosson
- Biologie du Développement, CNRS, Station zoologique, Villefranche sur Mer, France
| | - Mélanie Bonhivers
- Génomique fonctionnelle des Trypanosomatides, Université Bordeaux 2 and CNRS, Bordeaux, France
| | - Derrick Robinson
- Génomique fonctionnelle des Trypanosomatides, Université Bordeaux 2 and CNRS, Bordeaux, France
| | - Philippe Bastin
- Dynamique et Régulation des Génomes, Muséum National d'Histoire Naturelle, INSERM and CNRS, Paris, France
- Trypanosome Cell Biology Unit, Pasteur Institute and CNRS, Paris, France
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
30
|
Ralston KS, Hill KL. Trypanin, a component of the flagellar Dynein regulatory complex, is essential in bloodstream form African trypanosomes. PLoS Pathog 2006; 2:e101. [PMID: 17009870 PMCID: PMC1579245 DOI: 10.1371/journal.ppat.0020101] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Accepted: 08/23/2006] [Indexed: 11/18/2022] Open
Abstract
The Trypanosoma brucei flagellum is a multifunctional organelle with critical roles in motility, cellular morphogenesis, and cell division. Although motility is thought to be important throughout the trypanosome lifecycle, most studies of flagellum structure and function have been restricted to the procyclic lifecycle stage, and our knowledge of the bloodstream form flagellum is limited. We have previously shown that trypanin functions as part of a flagellar dynein regulatory system that transmits regulatory signals from the central pair apparatus and radial spokes to axonemal dyneins. Here we investigate the requirement for this dynein regulatory system in bloodstream form trypanosomes. We demonstrate that trypanin is localized to the flagellum of bloodstream form trypanosomes, in a pattern identical to that seen in procyclic cells. Surprisingly, trypanin RNA interference is lethal in the bloodstream form. These knockdown mutants fail to initiate cytokinesis, but undergo multiple rounds of organelle replication, accumulating multiple flagella, nuclei, kinetoplasts, mitochondria, and flagellum attachment zone structures. These findings suggest that normal flagellar beat is essential in bloodstream form trypanosomes and underscore the emerging concept that there is a dichotomy between trypanosome lifecycle stages with respect to factors that contribute to cell division and cell morphogenesis. This is the first time that a defined dynein regulatory complex has been shown to be essential in any organism and implicates the dynein regulatory complex and other enzymatic regulators of flagellar motility as candidate drug targets for the treatment of African sleeping sickness. African trypanosomes are protozoan parasites that cause African sleeping sickness, a fatal disease with devastating health and economic consequences. These parasites are indigenous to a 9 million-km2 area of sub-Saharan Africa where 60 million people live at risk of infection every day. In addition to the tremendous human health burden posed by trypanosomes, their infection of wild and domestic animals presents a barrier to sustained economic development of vast regions of otherwise productive land. Current drugs used for treatment of sleeping sickness are antiquated, toxic, and often ineffective; thus, there is a dire need for the development of innovative approaches for therapeutic intervention. Trypanosomes are highly motile and this motility requires coordinated regulation of axonemal dynein, a molecular motor that drives beating of the parasite's flagellum. In the present work, the authors demonstrate that the protein trypanin, which is part of a signaling system that regulates the flagellar dynein motor, is essential in bloodstream stage African trypanosomes. This surprising finding raises the possibility that numerous enzymes and regulatory proteins that are necessary for flagellar motility may represent novel targets for chemotherapeutic intervention in African sleeping sickness.
Collapse
Affiliation(s)
- Katherine S Ralston
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Kent L Hill
- Department of Microbiology, Immunology, and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
31
|
Ralston KS, Lerner AG, Diener DR, Hill KL. Flagellar motility contributes to cytokinesis in Trypanosoma brucei and is modulated by an evolutionarily conserved dynein regulatory system. EUKARYOTIC CELL 2006; 5:696-711. [PMID: 16607017 PMCID: PMC1459671 DOI: 10.1128/ec.5.4.696-711.2006] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The flagellum of Trypanosoma brucei is a multifunctional organelle with critical roles in motility and other aspects of the trypanosome life cycle. Trypanin is a flagellar protein required for directional cell motility, but its molecular function is unknown. Recently, a trypanin homologue in Chlamydomonas reinhardtii was reported to be part of a dynein regulatory complex (DRC) that transmits regulatory signals from central pair microtubules and radial spokes to axonemal dynein. DRC genes were identified as extragenic suppressors of central pair and/or radial spoke mutations. We used RNA interference to ablate expression of radial spoke (RSP3) and central pair (PF16) components individually or in combination with trypanin. Both rsp3 and pf16 single knockdown mutants are immotile, with severely defective flagellar beat. In the case of rsp3, this loss of motility is correlated with the loss of radial spokes, while in the case of pf16 the loss of motility correlates with an aberrant orientation of the central pair microtubules within the axoneme. Genetic interaction between trypanin and PF16 is demonstrated by the finding that loss of trypanin suppresses the pf16 beat defect, indicating that the DRC represents an evolutionarily conserved strategy for dynein regulation. Surprisingly, we discovered that four independent mutants with an impaired flagellar beat all fail in the final stage of cytokinesis, indicating that flagellar motility is necessary for normal cell division in T. brucei. These findings present the first evidence that flagellar beating is important for cell division and open the opportunity to exploit enzymatic activities that drive flagellar beat as drug targets for the treatment of African sleeping sickness.
Collapse
Affiliation(s)
- Katherine S Ralston
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, 609 Charles E. Young Dr., Los Angeles, CA 90095, USA
| | | | | | | |
Collapse
|
32
|
Kuribara S, Kato M, Kato-Minoura T, Numata O. Identification of a novel actin-related protein in Tetrahymena cilia. ACTA ACUST UNITED AC 2006; 63:437-46. [PMID: 16732560 DOI: 10.1002/cm.20136] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Actin is an ancient cytoskeletal protein that plays many essential roles in cell motility. In eukaryotes, its gene belongs to a highly conserved gene family, while the protein is also a member of an actin superfamily comprising various kinds of actin-related proteins (Arps). A ciliate, Tetrahymena, has a unique conventional actin. Data from the TIGR Tetrahymena genome project and our own research suggest the existence of 12 actin-like sequences: four conventional actins, two of Arp4, one each of Arp1, Arp2, Arp3, Arp5, and Arp6, and a novel actin-related protein, tArp. We cloned the entire cDNA sequences of Tetrahymena Arp2 (tArp2), Tetrahymena Arp3 (tArp3), and tArp for the work described herein. In phylogenetic analyses, tArp was not included in any Arp subfamily. Unlike other known Arps, tArp localizes in cilia, and its expression was upregulated after deciliation. To see the precise localization of tArp, cilia were fractionated and analyzed using specific antibodies. tArp was observed preferentially in the "outer-doublet" fraction, while actin was found in the "crude-dynein" fraction. In immunoelectron microscopy, most of the gold particles were found either on the outer-doublet or central-pair microtubules. These results suggest that tArp is a ciliary component and that it has a unique function in the formation and maintenance of cilia.
Collapse
Affiliation(s)
- Sayaka Kuribara
- Institute of Biological Sciences, University of Tsukuba, Tsukuba, Japan
| | | | | | | |
Collapse
|
33
|
Branche C, Kohl L, Toutirais G, Buisson J, Cosson J, Bastin P. Conserved and specific functions of axoneme components in trypanosome motility. J Cell Sci 2006; 119:3443-55. [PMID: 16882690 DOI: 10.1242/jcs.03078] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Trypanosoma brucei flagellum is unusual as it is attached along the cell body and contains, in addition to an apparently conventional axoneme, a structure called the paraflagellar rod, which is essential for cell motility. Here, we investigated flagellum behaviour in normal and mutant trypanosome cell lines where expression of genes encoding various axoneme proteins (PF16, PF20, DNAI1, LC2) had been silenced by RNAi. First, we show that the propulsive wave (normally used for forward motility) is abolished in the absence of outer dynein arms, whereas the reverse wave (normally used for changing direction) still occurs. Second, in contrast to Chlamydomonas--but like metazoa, the central pair adopts a fixed orientation during flagellum beating. This orientation becomes highly variable in central-pair- and outer-dynein-arm-mutants. Third, the paraflagellar rod contributes to motility by facilitating three-dimensional wave propagation and controlling cell shape. Fourth, motility is required to complete the last stage of cell division in both insect and bloodstream stages of the parasite. Finally, our study also reveals the conservation of molecular components of the trypanosome flagellum. Coupled to the ease of reverse genetics, it raises the interest of trypanosomes as model organisms to study cilia and flagella.
Collapse
Affiliation(s)
- Carole Branche
- INSERM U565 and CNRS UMR5153 and MNHN USM0503, Muséum National d'Histoire Naturelle, 43 rue Cuvier, 75231 Paris cedex 05, France
| | | | | | | | | | | |
Collapse
|
34
|
Corrêa-da-Silva MS, Fampa P, Lessa LP, Silva EDR, dos Santos Mallet JR, Saraiva EMB, Motta MCM. Colonization of Aedes aegypti midgut by the endosymbiont-bearing trypanosomatid Blastocrithidia culicis. Parasitol Res 2006; 99:384-91. [PMID: 16572337 DOI: 10.1007/s00436-006-0154-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Accepted: 02/07/2006] [Indexed: 10/24/2022]
Abstract
Monoxenous trypanosomatids inhabit invertebrate hosts throughout their life cycle. However, there have been cases of HIV-positive patients who have presented opportunistic infections caused by these protozoa, offering new perspectives to the study of interactions between monoxenics and hematophagous insect vectors. Some monoxenous trypanosomatids present a symbiotic bacterium in the cytoplasm, which seems to promote biochemical and morphological changes in the host trypanosomatids, such as alterations in plasma membrane carbohydrates and the reduction of the paraxial rod. In this work, we investigated the colonization of Aedes aegypti with Blastocrithidia culicis, an endosymbiont-bearing trypanosomatid. B. culicis remained in the insect digestive tract for 38 days after feeding. Optical microscopy analysis revealed an infection process characterized by a homogenous distribution of the trypanosomatid along the midgut epithelium; no preferential interaction of protozoa with any cell type was observed. Ultrastructural analysis showed that during the colonization process, trypanosomatids interacted mainly with midgut cells through their flagellum, which penetrates the microvilli preferentially near the tight junctions. Prolonged infections promoted insect midgut degradation, culminating with the arrival of protozoa in the hemocel. By demonstrating B. culicis colonization in a bloodsucking insect, we suggest that vector transmission of monoxenous trypanosomatids to vertebrate host may occur in nature.
Collapse
Affiliation(s)
- Miguel S Corrêa-da-Silva
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, CCS, Blogo G, subsolo, Ilha do Fundão, 21.941-900, Rio de Janeiro, RJ, Brazil
| | | | | | | | | | | | | |
Collapse
|
35
|
Oliveira DM, Gouveia JJS, Diniz NB, Pacheco ACL, Vasconcelos EJR, Diniz MC, Viana DA, Ferreira TD, Albuquerque MC, Fortier DC, Maia ARS, Costa LAC, Melo JOP, da Silva MC, Walter CA, Faria JO, Tome AR, Gomes MJN, Oliveira SMP, Araújo-Filho R, Costa RB, Maggioni R. Pathogenomics analysis of Leishmania spp.: flagellar gene families of putative virulence factors. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2005; 9:173-93. [PMID: 15969649 DOI: 10.1089/omi.2005.9.173] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The trypanosomatid flagellar apparatus contains conventional and unique features, whose roles in infectivity are still enigmatic. Although the flagellum and the flagellar pocket are critical organelles responsible for all vesicular trafficking between the cytoplasm and cell surface, still very little is known about their roles in pathogenesis and how molecules get to and from the flagellar pocket. The ongoing analysis of the genome sequences and proteome profiles of Leishmania major and L infantum, Trypanosoma cruzi, T. brucei, and T. gambiensi ( www.genedb.org ), coupled with our own work on L. chagasi (as part of the Brazilian Northeast Genome Program- www.progene.ufpe.br ), prompted us to scrutinize flagellar genes and proteins of Leishmania spp. promastigotes that could be virulence factors in leishmaniasis. We have identified some overlooked parasite factors such as the MNUDC-1 (a protein involved in nuclear development and genomic fusion) and SQS (an enzyme of sterol biosynthesis), among the described flagellar gene families. A database concerning the results of this work, as well as of other studies of Leishmania and its organelles, is available at http://nugen.lcc.uece.br/LPGate . It will serve as a convenient bioinformatics resource on genomics and pathology of the etiological agents of leishmaniasis.
Collapse
Affiliation(s)
- Diana M Oliveira
- Núcleo de Genômica e Bioinformática, Faculdade de Veterinária, Universidade Estadual do Ceara (UECE), Campus do Itaperi, Fortaleza, Ceara, Brazil.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Rusconi F, Durand-Dubief M, Bastin P. Functional complementation of RNA interference mutants in trypanosomes. BMC Biotechnol 2005; 5:6. [PMID: 15703078 PMCID: PMC549545 DOI: 10.1186/1472-6750-5-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Accepted: 02/09/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In many eukaryotic cells, double-stranded RNA (dsRNA) triggers RNA interference (RNAi), the specific degradation of RNA of homologous sequence. RNAi is now a major tool for reverse-genetics projects, including large-scale high-throughput screens. Recent reports have questioned the specificity of RNAi, raising problems in interpretation of RNAi-based experiments. RESULTS Using the protozoan Trypanosoma brucei as a model, we designed a functional complementation assay to ascertain that phenotypic effect(s) observed upon RNAi were due to specific silencing of the targeted gene. This was applied to a cytoskeletal gene encoding the paraflagellar rod protein 2 (TbPFR2), whose product is essential for flagellar motility. We demonstrate the complementation of TbPFR2, silenced via dsRNA targeting its UTRs, through the expression of a tagged RNAi-resistant TbPFR2 encoding a protein that could be immunolocalized in the flagellum. Next, we performed a functional complementation of TbPFR2, silenced via dsRNA targeting its coding sequence, through heterologous expression of the TbPFR2 orthologue gene from Trypanosoma cruzi: the flagellum regained its motility. CONCLUSIONS This work shows that functional complementation experiments can be readily performed in order to ascertain that phenotypic effects observed upon RNAi experiments are indeed due to the specific silencing of the targetted gene. Further, the results described here are of particular interest when reverse genetics studies cannot be easily achieved in organisms not amenable to RNAi. In addition, our strategy should constitute a firm basis to elaborate functional-dissection studies of genes from other organisms.
Collapse
Affiliation(s)
- Filippo Rusconi
- UMR5153 CNRS, USM0503 MNHN, U565 INSERM – 57, rue Cuvier – B.P. 26 – F-75231 – Paris Cedex 05 – France
| | - Mickaël Durand-Dubief
- UMR5153 CNRS, USM0503 MNHN, U565 INSERM – 57, rue Cuvier – B.P. 26 – F-75231 – Paris Cedex 05 – France
| | - Philippe Bastin
- UMR5153 CNRS, USM0503 MNHN, U565 INSERM – 57, rue Cuvier – B.P. 26 – F-75231 – Paris Cedex 05 – France
| |
Collapse
|
37
|
Abstract
Eukaryotic cilia and flagella are cytoskeletal organelles that are remarkably conserved from protists to mammals. Their basic unit is the axoneme, a well-defined cylindrical structure composed of microtubules and up to 250 associated proteins. These complex organelles are assembled by a dynamic process called intraflagellar transport. Flagella and cilia perform diverse motility and sensitivity functions in many different organisms. Trypanosomes are flagellated protozoa, responsible for various tropical diseases such as sleeping sickness and Chagas disease. In this review, we first describe general knowledge on the flagellum: its occurrence in the living world, its molecular composition, and its mode of assembly, with special emphasis on the exciting developments that followed the discovery of intraflagellar transport. We then present recent progress regarding the characteristics of the trypanosome flagellum, highlighting the original contributions brought by this organism. The most striking phenomenon is the involvement of the flagellum in several aspects of the trypanosome cell cycle, including cell morphogenesis, basal body migration, and cytokinesis.
Collapse
Affiliation(s)
- Linda Kohl
- INSERM U565, CNRS UMR5153, and MNHN USM 0503, Muséum National d'Histoire Naturelle, 75231 Paris, France
| | | |
Collapse
|
38
|
Gadelha C, LeBowitz JH, Manning J, Seebeck T, Gull K. Relationships between the major kinetoplastid paraflagellar rod proteins: a consolidating nomenclature. Mol Biochem Parasitol 2004; 136:113-5. [PMID: 15138073 DOI: 10.1016/j.molbiopara.2004.03.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2004] [Revised: 03/18/2004] [Accepted: 03/18/2004] [Indexed: 11/26/2022]
|
39
|
Pullen TJ, Ginger ML, Gaskell SJ, Gull K. Protein targeting of an unusual, evolutionarily conserved adenylate kinase to a eukaryotic flagellum. Mol Biol Cell 2004; 15:3257-65. [PMID: 15146060 PMCID: PMC452581 DOI: 10.1091/mbc.e04-03-0217] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The eukaryotic flagellum is a large structure into which specific constituent proteins must be targeted, transported and assembled after their synthesis in the cytoplasm. Using Trypanosoma brucei and a proteomic approach, we have identified and characterized a novel set of adenylate kinase proteins that are localized to the flagellum. These proteins represent unique isoforms that are targeted to the flagellum by an N-terminal extension to the protein and are incorporated into an extraaxonemal structure (the paraflagellar rod). We show that the N-terminal extension is both necessary for isoform location in the flagellum and sufficient for targeting of a green fluorescent protein reporter protein to the flagellum. Moreover, these N-terminal extension sequences are conserved in evolution and we find that they allow the identification of novel adenylate kinases in the genomes of humans and worms. Given the existence of specific isoforms of certain central metabolic enzymes, and targeting sequences for these isoforms, we suggest that these isoforms form part of a complex, "solid-phase" metabolic capability that is built into the eukaryotic flagellum.
Collapse
Affiliation(s)
- Timothy J Pullen
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | | | | | | |
Collapse
|
40
|
Durand-Dubief M, Kohl L, Bastin P. Efficiency and specificity of RNA interference generated by intra- and intermolecular double stranded RNA in Trypanosoma brucei. Mol Biochem Parasitol 2003; 129:11-21. [PMID: 12798502 DOI: 10.1016/s0166-6851(03)00071-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In many eukaryotes, double-stranded (ds) RNA leads to specific degradation of RNA of cognate sequence, a process termed RNA interference (RNAi). Here we used the protozoan Trypanosoma brucei as a model to investigate efficiency and specificity of RNAi generated by expression of long dsRNA of PFRA and PFRC genes, which code for flagellar proteins required for cell motility. Consequences of RNAi were monitored at all three levels: target RNA expression, protein expression and phenotype observation, using population or individual cell analysis. Expression of PFRA dsRNA from an inverted repeat was extremely efficient, knocking down PFRA RNA and PFRA protein, and producing a severe paralysis phenotype. Silencing by expression of PFRA dsRNA using a dual facing promoter system was also very efficient, producing a clear phenotype, although low amounts of PFRA RNA and PFRA protein were detected. Expression via the dual facing promoters of PAR2 dsRNA (83% overall identity with PFRA, including nine blocks of >20 nt total identity) did not produce significant reduction of total amounts of PFRA RNA or PFRA protein. However, individual cell analysis by immunofluorescence revealed that 10-60% cells (depending on subclones) exhibited lower PFRA amounts in their flagellum, producing a reduced-motility phenotype.
Collapse
Affiliation(s)
- Mickaël Durand-Dubief
- Unité INSERM U565 & CNRS UMR8646, Laboratoire de Biophysique, Muséum National d'Histoire Naturelle, 43 rue Cuvier, 75231 Paris Cedex 05, France
| | | | | |
Collapse
|
41
|
Affiliation(s)
- Kent L Hill
- Department of Microbiology, University of California at Los Angeles, Los Angeles, California 90095, USA.
| |
Collapse
|
42
|
Abstract
Cell fractionation, a methodological strategy for obtaining purified organelle preparations, has been applied successfully to parasitic protozoa by a number of investigators. Here we present and discuss the work of several groups that have obtained highly purified subcellular fractions from trypanosomatids, Apicomplexa and trichomonads, and whose work have added substantially to our knowledge of the cell biology of these parasites.
Collapse
Affiliation(s)
- Wanderley de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-900, Brasil.
| | | |
Collapse
|
43
|
Zaverucha do Valle T, Calabrese KS, Côrte-Real S, Baetas WC, Gonçalves da Costa SC. Trypanosoma cruzi: in vitro morphological alterations induced by actinomycin D. Pharmacology 2003; 67:55-8. [PMID: 12566848 DOI: 10.1159/000067741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2002] [Accepted: 06/05/2002] [Indexed: 11/19/2022]
Abstract
Actinomycin (ActD) is an antibiotic that binds DNA, preventing transcription. When a Trypanosoma cruzi infection in mice is treated with this drug, the parasite loses its ability to multiply, enabling protection. In this study, axenic cultured T. cruzi parasites were exposed to different concentrations of ActD (10, 20, and 50 microg/ml), all of them being able to inhibit growth and to alter the mobility. Nevertheless, the parasites remained alive and motile for at least 14 days. Scanning electron microscopy of trypomastigotes treated with 10 microg/ml of ActD for 24 h showed a modification in their morphology which suggests a change in the parasite cytoskeleton.
Collapse
Affiliation(s)
- Tânia Zaverucha do Valle
- Laboratório de Imunomodulação, Departamento de Protozoologia, Instituto Oswaldo Cruz, Rio de Janeiro, Brasil.
| | | | | | | | | |
Collapse
|
44
|
LaCount DJ, Barrett B, Donelson JE. Trypanosoma brucei FLA1 is required for flagellum attachment and cytokinesis. J Biol Chem 2002; 277:17580-8. [PMID: 11877446 DOI: 10.1074/jbc.m200873200] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The single flagellum of the protozoan parasite Trypanosoma brucei is attached along the length of the cell body by a complex structure that requires the FLA1 protein. We show here that inhibition of FLA1 expression by RNA interference in procyclic trypanosomes causes flagellar detachment and prevents cytokinesis. Despite being unable to divide, these cells undergo mitosis and develop a multinucleated phenotype. The Trypanosoma cruzi FLA1 homolog, GP72, is unable to complement either the flagellar detachment or cytokinesis defects in procyclic T. brucei that have been depleted of FLA1 by RNA interference. Instead, GP72 itself caused flagellar detachment when expressed in T. brucei. In contrast to T. brucei cells depleted of FLA1, procyclic T. brucei expressing GP72 continued to divide despite having detached flagella, demonstrating that flagellar attachment is not absolutely necessary for cytokinesis. We have also identified a FLA1-related gene (FLA2) whose sequence is similar but not identical to FLA1. Inhibition of FLA1 and FLA2 expression in bloodstream T. brucei caused flagellar detachment and blocked cytokinesis but did not inhibit mitosis. These experiments demonstrate that the FLA proteins are essential and suggest that in procyclic T. brucei, the FLA1 protein has separable functions in flagellar attachment and cytokinesis.
Collapse
Affiliation(s)
- Douglas J LaCount
- Department of Biochemistry, University of Iowa, Iowa City, Iowa 52242, USA
| | | | | |
Collapse
|
45
|
Moreira-Leite FF, Sherwin T, Kohl L, Gull K. A trypanosome structure involved in transmitting cytoplasmic information during cell division. Science 2001; 294:610-2. [PMID: 11641501 DOI: 10.1126/science.1063775] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
African trypanosomes are protozoan parasites that cause sleeping sickness in humans through a tsetse fly vector. The procyclic form of Trypanosoma brucei has a single, attached flagellum that describes a helical path along the cell from posterior to anterior. During division, a specific flagellum-flagellum connection is elaborated between the new and old flagellum. This connector was present only during cell duplication and was found to be involved in the replication of the helical cell pattern and polarity. This finding implicates the concept of cytotaxis in cell morphogenesis in trypanosomes.
Collapse
Affiliation(s)
- F F Moreira-Leite
- School of Biological Sciences, 2.205 Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | | | | | | |
Collapse
|
46
|
Abstract
RNA interference first described in Caenorhabditis elegans and transgene-induced post-transcriptional gene silencing first described in plants and fungi now appear as different means of activating a conserved and ancient mechanism that can protect genomes against viruses and transposons and perhaps also control expression of endogenous genes. We present here similar genetic interference phenomena in highly divergent protozoa, Trypanosoma and Paramecium, and look ahead to what contribution these microorganisms could bring to this fast-moving area.
Collapse
Affiliation(s)
- P Bastin
- University of Manchester, School of Biological Sciences, UK
| | | | | |
Collapse
|
47
|
Hill KL, Hutchings NR, Grandgenett PM, Donelson JE. T lymphocyte-triggering factor of african trypanosomes is associated with the flagellar fraction of the cytoskeleton and represents a new family of proteins that are present in several divergent eukaryotes. J Biol Chem 2000; 275:39369-78. [PMID: 10969087 DOI: 10.1074/jbc.m006907200] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The trypanosome cytoskeleton consists almost entirely of microtubule-based structures. Although alpha- and beta-tubulin from Trypanosoma brucei have been well characterized, much less is known about other cytoskeleton-associated proteins in trypanosomes. Using biochemical fractionation, we demonstrate here that T lymphocyte-triggering factor (TLTF) from T. brucei is a component of the detergent-resistant and Ca(2+)-resistant fraction of the parasite cytoskeleton. This fraction contains the flagellar apparatus and a subset of cytoskeletal protein complexes that together function in cell motility, cytokinesis, and organelle inheritance. We also show that TLTF-related genes are present in several highly divergent eukaryotic organisms. Although the function of the corresponding proteins is not known, the mammalian TLTF-like gene (GAS11; growth arrest-specific gene 11) is up-regulated in growth-arrested cells and is a candidate tumor suppressor (Whitmore, S. A., Settasatian, C., Crawford, J., Lower, K. M., McCallum, B., Seshadri, R., Cornelisse, C. J., Moerland, E. W., Cleton-Jansen, A. M., Tipping, A. J., Mathew, C. G., Savnio, M., Savoia, A., Verlander, P., Auerbach, A. D., Van Berkel, C., Pronk, J. C., Doggett, N. A., and Callen, D. F. (1998) Genomics 52, 325-331), suggestive of a role in coordinating cytoskeleton activities. Consistent with this possibility, we show that the human GAS11 protein contains a 144-amino acid domain that co-localizes with microtubules when fused to the green fluorescent protein and expressed in mammalian cells. These findings suggest that TLTF represents a newly defined protein family, whose members contribute to cytoskeleton function in species as diverse as protozoa and mammals.
Collapse
Affiliation(s)
- K L Hill
- Department of Biochemistry and Interdepartmental Genetics Ph.D. Program, University of Iowa, Iowa City, Iowa 52242, USA.
| | | | | | | |
Collapse
|
48
|
Bastin P, Pullen TJ, Moreira-Leite FF, Gull K. Inside and outside of the trypanosome flagellum:a multifunctional organelle. Microbes Infect 2000; 2:1865-74. [PMID: 11165931 DOI: 10.1016/s1286-4579(00)01344-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Amongst the earliest eukaryotes, trypanosomes have developed conventional organelles but sometimes with extreme features rarely seen in other organisms. This is the case of the flagellum, containing conventional and unique structures whose role in infectivity is still enigmatic.
Collapse
Affiliation(s)
- P Bastin
- Department of Biochemistry, School of Biological Sciences, University of Manchester, 2.205 Stopford Building, Oxford Road, M13 9PT, Manchester, UK.
| | | | | | | |
Collapse
|
49
|
de Souza W. A short review on the morphology of Trypanosoma cruzi: from 1909 to 1999. Mem Inst Oswaldo Cruz 2000; 94 Suppl 1:17-36. [PMID: 10677689 DOI: 10.1590/s0074-02761999000700003] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The morphology of Trypanosoma cruzi is reviewed since the initial description of Giemsa-stained preparations by Carlos Chagas until the most recent micrographs obtained with freeze-fracture techniques. Special emphasis is given to structures such as the cell surface, the flagellum, the kinetoplast, the reservosomes and the endocytic pathway, and the acidocalcisomes.
Collapse
Affiliation(s)
- W de Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil.
| |
Collapse
|
50
|
Ridgley E, Webster P, Patton C, Ruben L. Calmodulin-binding properties of the paraflagellar rod complex from Trypanosoma brucei. Mol Biochem Parasitol 2000; 109:195-201. [PMID: 10960180 DOI: 10.1016/s0166-6851(00)00246-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- E Ridgley
- Department of Biological Sciences, Southern Methodist University, Dallas, TX 75275, USA
| | | | | | | |
Collapse
|