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Borges AR, Link F, Engstler M, Jones NG. The Glycosylphosphatidylinositol Anchor: A Linchpin for Cell Surface Versatility of Trypanosomatids. Front Cell Dev Biol 2021; 9:720536. [PMID: 34790656 PMCID: PMC8591177 DOI: 10.3389/fcell.2021.720536] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 09/06/2021] [Indexed: 11/20/2022] Open
Abstract
The use of glycosylphosphatidylinositol (GPI) to anchor proteins to the cell surface is widespread among eukaryotes. The GPI-anchor is covalently attached to the C-terminus of a protein and mediates the protein’s attachment to the outer leaflet of the lipid bilayer. GPI-anchored proteins have a wide range of functions, including acting as receptors, transporters, and adhesion molecules. In unicellular eukaryotic parasites, abundantly expressed GPI-anchored proteins are major virulence factors, which support infection and survival within distinct host environments. While, for example, the variant surface glycoprotein (VSG) is the major component of the cell surface of the bloodstream form of African trypanosomes, procyclin is the most abundant protein of the procyclic form which is found in the invertebrate host, the tsetse fly vector. Trypanosoma cruzi, on the other hand, expresses a variety of GPI-anchored molecules on their cell surface, such as mucins, that interact with their hosts. The latter is also true for Leishmania, which use GPI anchors to display, amongst others, lipophosphoglycans on their surface. Clearly, GPI-anchoring is a common feature in trypanosomatids and the fact that it has been maintained throughout eukaryote evolution indicates its adaptive value. Here, we explore and discuss GPI anchors as universal evolutionary building blocks that support the great variety of surface molecules of trypanosomatids.
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Affiliation(s)
- Alyssa R Borges
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Fabian Link
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Markus Engstler
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Nicola G Jones
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
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Ramirez JL. An Evolutionary View of Trypanosoma Cruzi Telomeres. Front Cell Infect Microbiol 2020; 9:439. [PMID: 31998659 PMCID: PMC6967402 DOI: 10.3389/fcimb.2019.00439] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 12/06/2019] [Indexed: 11/21/2022] Open
Abstract
Like in most eukaryotes, the linear chromosomes of Trypanosoma cruzi end in a nucleoprotein structure called the telomere, which is preceded by regions of variable length called subtelomeres. Together telomeres and subtelomeres are dynamic sites where DNA sequence rearrangements can occur without compromising essential interstitial genes or chromosomal synteny. Good examples of subtelomeres involvement are the expansion of human olfactory receptors genes, variant surface antigens in Trypanosoma brucei, and Saccharomyces cerevisiae mating types. T. cruzi telomeres are made of long stretches of the hexameric repeat 5′-TTAGGG-OH-3′, and its subtelomeres are enriched in genes and pseudogenes from the large gene families RHS, TS and DGF1, DEAD/H-RNA helicase and N-acetyltransferase, intermingled with sequences of retrotransposons elements. In particular, members of the Trans-sialidase type II family appear to have played a role in shaping the current T. cruzi telomere structure. Although the structure and function of T. cruzi telomeric and subtelomeric regions have been documented, recent experiments are providing new insights into T. cruzi's telomere-subtelomere dynamics. In this review, I discuss the co-evolution of telomere, subtelomeres and the TS gene family, and the role that these regions may have played in shaping T. cruzi's genome.
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Affiliation(s)
- Jose Luis Ramirez
- Fundación Instituto de Estudios Avanzados and United Nations University UNU-BIOLAC, Caracas, Venezuela
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da Fonseca LM, da Costa KM, Chaves VDS, Freire-de-Lima CG, Morrot A, Mendonça-Previato L, Previato JO, Freire-de-Lima L. Theft and Reception of Host Cell's Sialic Acid: Dynamics of Trypanosoma Cruzi Trans-sialidases and Mucin-Like Molecules on Chagas' Disease Immunomodulation. Front Immunol 2019; 10:164. [PMID: 30787935 PMCID: PMC6372544 DOI: 10.3389/fimmu.2019.00164] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/18/2019] [Indexed: 12/27/2022] Open
Abstract
The last decades have produced a plethora of evidence on the role of glycans, from cell adhesion to signaling pathways. Much of that information pertains to their role on the immune system and their importance on the surface of many human pathogens. A clear example of this is the flagellated protozoan Trypanosoma cruzi, which displays on its surface a great variety of glycoconjugates, including O-glycosylated mucin-like glycoproteins, as well as multiple glycan-binding proteins belonging to the trans-sialidase (TS) family. Among the latter, different and concurrently expressed molecules may present or not TS activity, and are accordingly known as active (aTS) and inactive (iTS) members. Over the last thirty years, it has been well described that T. cruzi is unable to synthesize sialic acid (SIA) on its own, making use of aTS to steal the host's SIA. Although iTS did not show enzymatic activity, it retains a substrate specificity similar to aTS (α-2,3 SIA-containing glycotopes), displaying lectinic properties. It is accepted that aTS members act as virulence factors in mammals coursing the acute phase of the T. cruzi infection. However, recent findings have demonstrated that iTS may also play a pathogenic role during T. cruzi infection, since it modulates events related to adhesion and invasion of the parasite into the host cells. Since both aTS and iTS proteins share structural substrate specificity, it might be plausible to speculate that iTS proteins are able to assuage and/or attenuate biological phenomena depending on the catalytic activity displayed by aTS members. Since SIA-containing glycotopes modulate the host immune system, it should not come as any surprise that changes in the sialylation of parasite's mucin-like molecules, as well as host cell glycoconjugates might disrupt critical physiological events, such as the building of effective immune responses. This review aims to discuss the importance of mucin-like glycoproteins and both aTS and iTS for T. cruzi biology, as well as to present a snapshot of how disturbances in both parasite and host cell sialoglycophenotypes may facilitate the persistence of T. cruzi in the infected mammalian host.
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Affiliation(s)
- Leonardo Marques da Fonseca
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Kelli Monteiro da Costa
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Victoria de Sousa Chaves
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Célio Geraldo Freire-de-Lima
- Laboratório de Imunomodulação, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alexandre Morrot
- Laboratório de Pesquisa em Tuberculose, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Laboratório de Imunoparasitologia, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Lucia Mendonça-Previato
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Jose Osvaldo Previato
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leonardo Freire-de-Lima
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Seregni E, Botti C, Massaron S, Lombardo C, Capobianco A, Bogni A, Bombardieri E. Structure, Function and Gene Expression of Epithelial Mucins. TUMORI JOURNAL 2018; 83:625-32. [PMID: 9267478 DOI: 10.1177/030089169708300301] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this review the main characteristics, i.e., structure, function and gene expression, of the different mucins are discussed. Mucin-type molecules consist of a core protein moiety (apomucin) where a number of carbohydrate chains are attached to serines and threonines by glycosidic bonds. O-linked carbohydrates form up to 80% of the molecule and the length of the glucidic side chains varies from one to more than 20 residues. At least eight mucin-like genes have been isolated so far, and the main characteristic is the presence of a central domain composed of a variable number of “tandem repeats”. The sequence homology of the central domain among the different members of the mucin-type family is limited, indicating that this internal domain is unique for each mucin. Thanks to the integrated results of genetic, immunological and biochemical studies, it is now possible to identify eight apomucin genes, namely MUC1, MUC2, MUC3, MUC4, MUC5AC, MUC5B, MUC6 and MUC7. MUC1 is the best characterized mucin and it is expressed on the apical surface of most polarized epithelial cells. The MUC1 gene has been cloned and sequenced. The MUC2 gene encodes a typical secretory gel-forming mucin which represents the predominant form in human intestinal and colon tissues. Another intestinal mucin is MUC3. The MUC4, MUC5AC and MUC5B genes have been isolated from a bronchial tissue cDNA library. The MUC4 and MUC5AC genes are mainly expressed in the respiratory tract, in gastric and reproductive mucosa, while MUC5B is highly detectable only in the bronchial glands. The MUC6 gene is expressed by gastric tissue and, recently, MUC7 has been cloned and sequenced using a salivary cDNA library.
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Affiliation(s)
- E Seregni
- Nuclear Medicine Department, Istituto Nazionale per lo Studio e la Cura dei Tumori, Milan
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Pech-Canul ÁDLC, Monteón V, Solís-Oviedo RL. A Brief View of the Surface Membrane Proteins from Trypanosoma cruzi. J Parasitol Res 2017; 2017:3751403. [PMID: 28656101 PMCID: PMC5474541 DOI: 10.1155/2017/3751403] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/31/2017] [Accepted: 04/27/2017] [Indexed: 12/22/2022] Open
Abstract
Trypanosoma cruzi is the causal agent of Chagas' disease which affects millions of people around the world mostly in Central and South America. T. cruzi expresses a wide variety of proteins on its surface membrane which has an important role in the biology of these parasites. Surface molecules of the parasites are the result of the environment to which the parasites are exposed during their life cycle. Hence, T. cruzi displays several modifications when they move from one host to another. Due to the complexity of this parasite's cell surface, this review presents some membrane proteins organized as large families, as they are the most abundant and/or relevant throughout the T. cruzi membrane.
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Affiliation(s)
- Ángel de la Cruz Pech-Canul
- Centre for Biomolecular Sciences, The University of Nottingham, University Park, University Blvd, Nottingham NG7 2RD, UK
| | - Victor Monteón
- Investigaciones Biomédicas, Universidad Autónoma de Campeche, Av. Patricio Trueba s/n, Col. Lindavista, 24039 Campeche, CAM, Mexico
| | - Rosa-Lidia Solís-Oviedo
- Centre for Biomolecular Sciences, The University of Nottingham, University Park, University Blvd, Nottingham NG7 2RD, UK
- Investigaciones Biomédicas, Universidad Autónoma de Campeche, Av. Patricio Trueba s/n, Col. Lindavista, 24039 Campeche, CAM, Mexico
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Morrot A, Villar SR, González FB, Pérez AR. Evasion and Immuno-Endocrine Regulation in Parasite Infection: Two Sides of the Same Coin in Chagas Disease? Front Microbiol 2016; 7:704. [PMID: 27242726 PMCID: PMC4876113 DOI: 10.3389/fmicb.2016.00704] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 04/28/2016] [Indexed: 12/16/2022] Open
Abstract
Chagas disease is a serious illness caused by the protozoan parasite Trypanosoma cruzi. Nearly 30% of chronically infected people develop cardiac, digestive, or mixed alterations, suggesting a broad range of host-parasite interactions that finally impact upon chronic disease outcome. The ability of T. cruzi to persist and cause pathology seems to depend on diverse factors like T. cruzi strains, the infective load and the route of infection, presence of virulence factors, the parasite capacity to avoid protective immune response, the strength and type of host defense mechanisms and the genetic background of the host. The host-parasite interaction is subject to a constant neuro-endocrine regulation that is thought to influence the adaptive immune system, and as the infection proceeds it can lead to a broad range of outcomes, ranging from pathogen elimination to its continued persistence in the host. In this context, T. cruzi evasion strategies and host defense mechanisms can be envisioned as two sides of the same coin, influencing parasite persistence and different outcomes observed in Chagas disease. Understanding how T. cruzi evade host's innate and adaptive immune response will provide important clues to better dissect mechanisms underlying the pathophysiology of Chagas disease.
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Affiliation(s)
- Alexandre Morrot
- Institute of Microbiology, Federal University of Rio de Janeiro Rio de Janeiro, Brazil
| | - Silvina R Villar
- Institute of Clinical and Experimental Immunology of Rosario, CONICET, National University of RosarioRosario, Argentina; Faculty of Medical Sciences, National University of RosarioRosario, Argentina
| | - Florencia B González
- Institute of Clinical and Experimental Immunology of Rosario, CONICET, National University of RosarioRosario, Argentina; Faculty of Medical Sciences, National University of RosarioRosario, Argentina
| | - Ana R Pérez
- Institute of Clinical and Experimental Immunology of Rosario, CONICET, National University of RosarioRosario, Argentina; Faculty of Medical Sciences, National University of RosarioRosario, Argentina
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Immune Evasion Strategies of Trypanosoma cruzi. J Immunol Res 2015; 2015:178947. [PMID: 26240832 PMCID: PMC4512591 DOI: 10.1155/2015/178947] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 12/31/2014] [Indexed: 01/03/2023] Open
Abstract
Microbes have evolved a diverse range of strategies to subvert the host immune system. The protozoan parasite Trypanosoma cruzi, the causative agent of Chagas disease, provides a good example of such adaptations. This parasite targets a broad spectrum of host tissues including both peripheral and central lymphoid tissues. Rapid colonization of the host gives rise to a systemic acute response which the parasite must overcome. The parasite in fact undermines both innate and adaptive immunity. It interferes with the antigen presenting function of dendritic cells via an action on host sialic acid-binding Ig-like lectin receptors. These receptors also induce suppression of CD4(+) T cells responses, and we presented evidence that the sialylation of parasite-derived mucins is required for the inhibitory effects on CD4 T cells. In this review we highlight the major mechanisms used by Trypanosoma cruzi to overcome host immunity and discuss the role of parasite colonization of the central thymic lymphoid tissue in chronic disease.
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Morrot A. The Role of Sialic Acid-Binding Receptors (Siglecs) in the Immunomodulatory Effects of Trypanosoma cruzi Sialoglycoproteins on the Protective Immunity of the Host. SCIENTIFICA 2013; 2013:965856. [PMID: 24455435 PMCID: PMC3885277 DOI: 10.1155/2013/965856] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Accepted: 12/10/2013] [Indexed: 06/03/2023]
Abstract
Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and is an important endemic infection in Latin America. Lately, it has also become a health concern in the United States and Europe. Most of the immunomodulatory mechanisms associated with this parasitic infection have been attributed to mucin-like molecules on the T. cruzi surface. Mucins are high molecular weight glycoproteins that are involved in regulating diverse cellular activities in both normal and pathological conditions. In Trypanosoma cruzi infection, the parasite-derived mucins are the main acceptors of sialic acid and it has been suggested that they play a role in various host-parasite interactions during the course of Chagas disease. Recently, we have presented evidence that sialylation of the mucins is required for the inhibitory effects on CD4(+) T cells. In what follows we propose that signaling via sialic acid-binding Ig-like lectin receptors for these highly sialylated structures on host cells contributes to the arrest of cell cycle progression in the G1 phase and may allow the parasite to modulate the immune system of the host.
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Affiliation(s)
- Alexandre Morrot
- Institute of Microbiology, Federal University of Rio de Janeiro, CCS, Sala D1-035, Avenida Carlos Chagas Filho 373, Cidade Universitária, Ilha do Fundão, 21.941-902 Rio de Janeiro, RJ, Brazil
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9
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Nunes MP, Fortes B, Silva-Filho JL, Terra-Granado E, Santos L, Conde L, de Araújo Oliveira I, Freire-de-Lima L, Martins MV, Pinheiro AAS, Takyia CM, Freire-de-Lima CG, Todeschini AR, DosReis GA, Morrot A. Inhibitory effects of Trypanosoma cruzi sialoglycoproteins on CD4+ T cells are associated with increased susceptibility to infection. PLoS One 2013; 8:e77568. [PMID: 24204874 PMCID: PMC3810146 DOI: 10.1371/journal.pone.0077568] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 09/03/2013] [Indexed: 01/16/2023] Open
Abstract
Background The Trypanosoma cruzi infection is associated with severe T cell unresponsiveness to antigens and mitogens characterized by decreased IL-2 synthesis. Trypanosoma cruzi mucin (Tc Muc) has been implicated in this phenomenom. These molecules contain a unique type of glycosylation consisting of several sialylated O-glycans linked to the protein backbone via N-acetylglucosamine residues. Methodology/Principal Findings In this study, we evaluated the ability of Tc Muc to modulate the activation of CD4+ T cells. Our data show that cross-linking of CD3 on naïve CD4+ T cells in the presence of Tc Muc resulted in the inhibition of both cytokine secretion and proliferation. We further show that the sialylated O-Linked Glycan residues from tc mucin potentiate the suppression of T cell response by inducing G1-phase cell cycle arrest associated with upregulation of mitogen inhibitor p27kip1. These inhibitory effects cannot be reversed by the addition of exogenous IL-2, rendering CD4+ T cells anergic when activated by TCR triggering. Additionally, in vivo administration of Tc Muc during T. cruzi infection enhanced parasitemia and aggravated heart damage. Analysis of recall responses during infection showed lower frequencies of IFN-γ producing CD4+ T cells in the spleen of Tc Muc treated mice, compared to untreated controls. Conclusions/Significance Our results indicate that Tc Muc mediates inhibitory efects on CD4+ T expansion and cytokine production, by blocking cell cycle progression in the G1 phase. We propose that the sialyl motif of Tc Muc is able to interact with sialic acid-binding Ig-like lectins (Siglecs) on CD4+ T cells, which may allow the parasite to modulate the immune system.
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Affiliation(s)
| | - Bárbara Fortes
- Institute of Microbiology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - João Luiz Silva-Filho
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | | | | | | | - Isadora de Araújo Oliveira
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leonardo Freire-de-Lima
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Ana Acacia Sá Pinheiro
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Christina Maeda Takyia
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Adriane Regina Todeschini
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - George Alexandre DosReis
- Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alexandre Morrot
- Institute of Microbiology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
- * E-mail: (MPN); (AM)
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Barrias ES, de Carvalho TMU, De Souza W. Trypanosoma cruzi: Entry into Mammalian Host Cells and Parasitophorous Vacuole Formation. Front Immunol 2013; 4:186. [PMID: 23914186 PMCID: PMC3730053 DOI: 10.3389/fimmu.2013.00186] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 06/25/2013] [Indexed: 11/29/2022] Open
Abstract
Trypanosoma cruzi, the causative agent of Chagas disease, is transmitted to vertebrate hosts by blood-sucking insects. This protozoan is an obligate intracellular parasite. The infective forms of the parasite are the metacyclic trypomastigotes, amastigotes, and bloodstream trypomastigotes. The recognition between the parasite and mammalian host cell, involves numerous molecules present in both cell types, and similar to several intracellular pathogens, T. cruzi is internalized by host cells via multiple endocytic pathways. Morphological studies demonstrated that after the interaction of the infective forms of T. cruzi with phagocytic or non-phagocytic cell types, plasma membrane (PM) protrusions can form, showing similarity with those observed during canonical phagocytosis or macropinocytic events. Additionally, several molecules known to be molecular markers of membrane rafts, macropinocytosis, and phagocytosis have been demonstrated to be present at the invasion site. These events may or may not depend on the host cell lysosomes and cytoskeleton. In addition, after penetration, components of the host endosomal-lysosomal system, such as early endosomes, late endosomes, and lysosomes, participate in the formation of the nascent parasitophorous vacuole (PV). Dynamin, a molecule involved in vesicle formation, has been shown to be involved in the PV release from the host cell PM. This review focuses on the multiple pathways that T. cruzi can use to enter the host cells until complete PV formation. We will describe different endocytic processes, such as phagocytosis, macropinocytosis, and endocytosis using membrane microdomains and clathrin-dependent endocytosis and show results that are consistent with their use by this smart parasite. We will also discuss others mechanisms that have been described, such as active penetration and the process that takes advantage of cell membrane wound repair.
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Affiliation(s)
- Emile Santos Barrias
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Biologia, Instituto Nacional de Metrologia, Qualidade e Tecnologia – Inmetro Duque de Caxias, Rio de Janeiro, Brazil
| | - Tecia Maria Ulisses de Carvalho
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Wanderley De Souza
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Biologia, Instituto Nacional de Metrologia, Qualidade e Tecnologia – Inmetro Duque de Caxias, Rio de Janeiro, Brazil
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11
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Cánepa GE, Mesías AC, Yu H, Chen X, Buscaglia CA. Structural features affecting trafficking, processing, and secretion of Trypanosoma cruzi mucins. J Biol Chem 2012; 287:26365-76. [PMID: 22707724 DOI: 10.1074/jbc.m112.354696] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Trypanosoma cruzi is wrapped by a dense coat of mucin-type molecules encoded by complex gene families termed TcSMUG and TcMUC, which are expressed in the insect- and mammal-dwelling forms of the parasite, respectively. Here, we dissect the contribution of distinct post-translational modifications on the trafficking of these glycoconjugates. In vivo tracing and characterization of tagged-variants expressed by transfected epimastigotes indicate that although the N-terminal signal peptide is responsible for targeting TcSMUG products to the endoplasmic reticulum (ER), the glycosyl phosphatidylinositol (GPI)-anchor likely functions as a forward transport signal for their timely progression along the secretory pathway. GPI-minus variants accumulate in the ER, with only a minor fraction being ultimately released to the medium as anchorless products. Secreted products, but not ER-accumulated ones, display several diagnostic features of mature mucin-type molecules including extensive O-type glycosylation, Galf-based epitopes recognized by monoclonal antibodies, and terminal Galp residues that become readily sialylated upon addition of parasite trans-sialidases. Processing of N-glycosylation site(s) is dispensable for the overall TcSMUG mucin-type maturation and secretion. Despite undergoing different O-glycosylation elaboration, TcMUC reporters yielded quite similar results, thus indicating that (i) molecular trafficking signals are structurally and functionally conserved between mucin families, and (ii) TcMUC and TcSMUG products are recognized and processed by a distinct repertoire of stage-specific glycosyltransferases. Thus, using the fidelity of a homologous expression system, we have defined some biosynthetic aspects of T. cruzi mucins, key molecules involved in parasite protection and virulence.
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Affiliation(s)
- Gaspar E Cánepa
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo Ugalde," Av. 25 de Mayo y Francia, Campus UNSAM, San Martín 1650, Buenos Aires, Argentina
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12
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Teixeira SM, de Paiva RMC, Kangussu-Marcolino MM, Darocha WD. Trypanosomatid comparative genomics: Contributions to the study of parasite biology and different parasitic diseases. Genet Mol Biol 2012; 35:1-17. [PMID: 22481868 PMCID: PMC3313497 DOI: 10.1590/s1415-47572012005000008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 10/18/2011] [Indexed: 01/23/2023] Open
Abstract
In 2005, draft sequences of the genomes of Trypanosoma brucei, Trypanosoma cruzi and Leishmania major, also known as the Tri-Tryp genomes, were published. These protozoan parasites are the causative agents of three distinct insect-borne diseases, namely sleeping sickness, Chagas disease and leishmaniasis, all with a worldwide distribution. Despite the large estimated evolutionary distance among them, a conserved core of ~6,200 trypanosomatid genes was found among the Tri-Tryp genomes. Extensive analysis of these genomic sequences has greatly increased our understanding of the biology of these parasites and their host-parasite interactions. In this article, we review the recent advances in the comparative genomics of these three species. This analysis also includes data on additional sequences derived from other trypanosmatid species, as well as recent data on gene expression and functional genomics. In addition to facilitating the identification of key parasite molecules that may provide a better understanding of these complex diseases, genome studies offer a rich source of new information that can be used to define potential new drug targets and vaccine candidates for controlling these parasitic infections.
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Affiliation(s)
- Santuza M Teixeira
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
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Teixeira SM, El-Sayed NM, Araújo PR. The genome and its implications. ADVANCES IN PARASITOLOGY 2011; 75:209-30. [PMID: 21820558 DOI: 10.1016/b978-0-12-385863-4.00010-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Trypanosoma cruzi has a heterogeneous population composed of a pool of strains that circulate in the domestic and sylvatic cycles. Genome sequencing of the clone CL Brener revealed a highly repetitive genome of about 110Mb containing an estimated 22,570 genes. Because of its hybrid nature, sequences representing the two haplotypes have been generated. In addition, a repeat content close to 50% made the assembly of the estimated 41 pairs of chromosomes quite challenging. Similar to other trypanosomatids, the organization of T. cruzi chromosomes was found to be very peculiar, with protein-coding genes organized in long polycistronic transcription units encoding 20 or more proteins in one strand separated by strand switch regions. Another remarkable feature of the T. cruzi genome is the massive expansion of surface protein gene families. Because of the high genetic diversity of the T. cruzi population, sequencing of additional strains and comparative genomic and transcriptome analyses are in progress. Five years after its publication, the genome data have proven to be an essential tool for the study of T. cruzi and increasing efforts to translate this knowledge into the development of new modes of intervention to control Chagas disease are underway.
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Affiliation(s)
- Santuza M Teixeira
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
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14
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Review on Trypanosoma cruzi: Host Cell Interaction. Int J Cell Biol 2010; 2010. [PMID: 20811486 PMCID: PMC2926652 DOI: 10.1155/2010/295394] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Revised: 05/11/2010] [Accepted: 06/04/2010] [Indexed: 12/21/2022] Open
Abstract
Trypanosoma cruzi, the causative agent of Chagas' disease, which affects a large number of individuals in Central and South America, is transmitted to vertebrate hosts by blood-sucking insects. This protozoan is an obligate intracellular parasite. The infective forms of the parasite are metacyclic and bloodstream trypomastigote and amastigote. Metacyclic trypomastigotes are released with the feces of the insect while amastigotes and bloodstream trypomastigotes are released from the infected host cells of the vertebrate host after a complex intracellular life cycle. The recognition between parasite and mammalian host cell involves numerous molecules present in both cell types. Here, we present a brief review of the interaction between Trypanosoma cruzi and its host cells, mainly emphasizing the mechanisms and molecules that participate in the T. cruzi invasion process of the mammalian cells.
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15
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Affiliation(s)
- Rosa M de Lederkremer
- Departamento de Quimica Organica, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina
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16
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Bartholomeu DC, Cerqueira GC, Leão ACA, daRocha WD, Pais FS, Macedo C, Djikeng A, Teixeira SMR, El-Sayed NM. Genomic organization and expression profile of the mucin-associated surface protein (masp) family of the human pathogen Trypanosoma cruzi. Nucleic Acids Res 2009; 37:3407-17. [PMID: 19336417 PMCID: PMC2691823 DOI: 10.1093/nar/gkp172] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A novel large multigene family was recently identified in the human pathogen Trypanosoma cruzi, causative agent of Chagas disease, and corresponds to ∼6% of the parasite diploid genome. The predicted gene products, mucin-associated surface proteins (MASPs), are characterized by highly conserved N- and C-terminal domains and a strikingly variable and repetitive central region. We report here an analysis of the genomic organization and expression profile of masp genes. Masps are not randomly distributed throughout the genome but instead are clustered with genes encoding mucin and other surface protein families. Masp transcripts vary in size, are preferentially expressed during the trypomastigote stage and contain highly conserved 5′ and 3′ untranslated regions. A sequence analysis of a trypomastigote cDNA library reveals the expression of multiple masp variants with a bias towards a particular masp subgroup. Immunofluorescence assays using antibodies generated against a MASP peptide reveals that the expression of particular MASPs at the cell membrane is limited to subsets of the parasite population. Western blots of phosphatidylinositol-specific phospholipase C (PI-PLC)-treated parasites suggest that MASP may be GPI-anchored and shed into the medium culture, thus contributing to the large repertoire of parasite polypeptides that are exposed to the host immune system.
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Affiliation(s)
- Daniella C Bartholomeu
- Department of Parasitology, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil.
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17
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Villalta F, Scharfstein J, Ashton AW, Tyler KM, Guan F, Mukherjee S, Lima MF, Alvarez S, Weiss LM, Huang H, Machado FS, Tanowitz HB. Perspectives on the Trypanosoma cruzi-host cell receptor interactions. Parasitol Res 2009; 104:1251-60. [PMID: 19283409 DOI: 10.1007/s00436-009-1383-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2008] [Accepted: 02/25/2009] [Indexed: 01/10/2023]
Abstract
Chagas disease is caused by the parasite Trypanosoma cruzi. The critical initial event is the interaction of the trypomastigote form of the parasite with host receptors. This review highlights recent observations concerning these interactions. Some of the key receptors considered are those for thromboxane, bradykinin, and for the nerve growth factor TrKA. Other important receptors such as galectin-3, thrombospondin, and laminin are also discussed. Investigation into the molecular biology and cell biology of host receptors for T. cruzi may provide novel therapeutic targets.
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Affiliation(s)
- Fernando Villalta
- Department of Microbial Pathogenesis and Immune Response, Meharry Medical College, Nashville, TN, USA.
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18
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Buscaglia CA, Campo VA, Frasch ACC, Di Noia JM. Trypanosoma cruzi surface mucins: host-dependent coat diversity. Nat Rev Microbiol 2006; 4:229-36. [PMID: 16489349 DOI: 10.1038/nrmicro1351] [Citation(s) in RCA: 209] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The surface of the protozoan parasite Trypanosoma cruzi is covered in mucins, which contribute to parasite protection and to the establishment of a persistent infection. Their importance is highlighted by the fact that the approximately 850 mucin-encoding genes comprise approximately 1% of the parasite genome and approximately 6% of all predicted T. cruzi genes. The coordinate expression of a large repertoire of mucins containing variable regions in the mammal-dwelling stages of the T. cruzi life cycle suggests a possible strategy to thwart the host immune response. Here, we discuss the expression profiling of T. cruzi mucins, the mechanisms leading to the acquisition of mucin diversity and the possible consequences of a mosaic surface coat in the interplay between parasite and host.
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Affiliation(s)
- Carlos A Buscaglia
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de General San Martn-CONICET, San Martín (1650), Buenos Aires, Argentina
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19
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Campo VA, Buscaglia CA, Di Noia JM, Frasch ACC. Immunocharacterization of the mucin-type proteins from the intracellular stage of Trypanosoma cruzi. Microbes Infect 2006; 8:401-9. [PMID: 16253534 DOI: 10.1016/j.micinf.2005.07.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Revised: 07/05/2005] [Accepted: 07/06/2005] [Indexed: 11/27/2022]
Abstract
The surface of Trypanosoma cruzi is covered by different groups of mucins that are differentially expressed during the parasite life cycle. We have previously identified the major mucins from the bloodstream trypomastigote stage. Here, we present additional evidence that together with our previous observations allows for the identification of a second mucin group also expressed in the mammal-dwelling stages, but predominant in the intracellular amastigote. These mucins are encoded by many genes, are mostly composed of tandem repeats and are highly conserved except for an exposed hypervariable (HV) N-terminal peptide. Antibodies against HV-peptides are restricted to approximately 50% of the chronically infected human population, are monospecific (i.e. directed towards a single HV), and display low-avidity. In contrast, immunization with a single HV-peptide triggers high-avidity, cross-reacting humoral responses against multiple HV sequences, but not against other T. cruzi surface antigens. The diversity present in the HV regions and the characteristics of the antibody response against them suggest a role of these molecules in eluding and/or modulating the mammalian host immune system.
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Affiliation(s)
- Vanina A Campo
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, Universidad Nacional de General San Martín-CONICET, Av. General Paz 5445 edificio 24, San Martín (1650), Buenos Aires, Argentina.
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20
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Abate T, Rincón M, Díaz-Bello Z, Spencer L, Rodríguez-Acosta A. A mucin like gene different from the previously reported members of the mucin like gene families is transcribed in Trypanosoma cruzi but not in Trypanosoma rangeli. Mem Inst Oswaldo Cruz 2005; 100:391-5. [PMID: 16113887 DOI: 10.1590/s0074-02762005000400009] [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] [Indexed: 11/21/2022] Open
Abstract
Trypanosoma cruzi expresses mucin like glycoproteins encoded by a complex multigene family. In this work, we report the transcription in T. cruzi but not in T. rangeli of a mucin type gene automatically annotated by the T. cruzi genome project. The gene showed no nucleotide similarities with the previously reported T. cruzi mucin like genes, although the computational analysis of the deduced protein showed that it has the characteristic features of mucins: a signal peptide sequence, O-glycosylation sites, and glycosylphosphatidylinositol (GPI) anchor sequence. The presence in this gene of N-terminal and C-terminal coding sequences common to other annotated mucin like genes suggests the existence of a new mucin like gene family.
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Affiliation(s)
- Teresa Abate
- Instituto de Medicina Tropical Dr. Félix Pifano, Caracas 1041-A, DF, Venezuela.
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21
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Bhatia V, Sinha M, Luxon B, Garg N. Utility of the Trypanosoma cruzi sequence database for identification of potential vaccine candidates by in silico and in vitro screening. Infect Immun 2004; 72:6245-54. [PMID: 15501750 PMCID: PMC523045 DOI: 10.1128/iai.72.11.6245-6254.2004] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Glycosylphosphatidylinositol (GPI)-anchored proteins are abundantly expressed in the infective and intracellular stages of Trypanosoma cruzi and are recognized as antigenic targets by both the humoral and cellular arms of the immune system. Previously, we demonstrated the efficacy of genes encoding GPI-anchored proteins in eliciting partially protective immunity to T. cruzi infection and disease, suggesting their utility as vaccine candidates. For the identification of additional vaccine targets, in this study we screened the T. cruzi expressed sequence tag (EST) and genomic sequence survey (GSS) databases. By applying a variety of web-based genome-mining tools to the analysis of approximately 2,500 sequences, we identified 348 (37.6%) EST and 260 (17.4%) GSS sequences encoding novel parasite-specific proteins. Of these, 19 sequences exhibited the characteristics of secreted and/or membrane-associated GPI proteins. Eight of the selected sequences were amplified to obtain genes TcG1, TcG2, TcG3, TcG4, TcG5, TcG6, TcG7, and TcG8 (TcG1-TcG8) which are expressed in different developmental stages of the parasite and conserved in the genome of a variety of T. cruzi strains. Flow cytometry confirmed the expression of the antigens encoded by the cloned genes as surface proteins in trypomastigote and/or amastigote stages of T. cruzi. When delivered as a DNA vaccine, genes TcG1-TcG6 elicited a parasite-specific antibody response in mice. Except for TcG5, antisera to genes TcG1-TcG6 exhibited trypanolytic activity against the trypomastigote forms of T. cruzi, a property known to correlate with the immune control of T. cruzi. Taken together, our results validate the applicability of bioinformatics in genome mining, resulting in the identification of T. cruzi membrane-associated proteins that are potential vaccine candidates.
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Affiliation(s)
- Vandanajay Bhatia
- Department of Microbiology and Immunology, University of Texas Medical Branch, 301 University Blvd, Galveston 77555, USA
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22
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Buscaglia CA, Campo VA, Di Noia JM, Torrecilhas ACT, De Marchi CR, Ferguson MAJ, Frasch ACC, Almeida IC. The Surface Coat of the Mammal-dwelling Infective Trypomastigote Stage of Trypanosoma cruzi Is Formed by Highly Diverse Immunogenic Mucins. J Biol Chem 2004; 279:15860-9. [PMID: 14749325 DOI: 10.1074/jbc.m314051200] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A thick coat of mucin-like glycoproteins covers the surface of Trypanosoma cruzi and plays a crucial role in parasite protection and infectivity and host immunomodulation. The appealing candidate genes coding for the mucins of the mammal-dwelling stages define a heterogeneous family termed TcMUC, which comprises up to 700 members, thus precluding a genetic approach to address the protein core identity. Here, we demonstrate by multiple approaches that the TcMUC II genes code for the majority of trypomastigote mucins. These molecules display a variable, non-repetitive, highly O-glycosylated central domain, followed by a short conserved C terminus and a glycosylphosphatidylinositol anchor. A simultaneous expression of multiple TcMUC II gene products was observed. Moreover, the C terminus of TcMUC II mucins, but not their central domain, elicited strong antibody responses in patients with Chagas' disease and T. crusi infected animals. This highly diverse coat of mucins may represent a refined parasite strategy to elude the mammalian host immune system.
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Affiliation(s)
- Carlos A Buscaglia
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, Universidad Nacional de General San Martín, San Martín, Buenos Aires, Argentina
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23
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Carro D, García-Martinez J, Pérez-Ortín JE, Piña B. Structural characterization of chromosome I size variants from a natural yeast strain. Yeast 2003; 20:171-83. [PMID: 12518320 DOI: 10.1002/yea.955] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Many yeast strains isolated from the wild show karyotype instability during vegetative growth, with rearrangement rates of up to 10(-2) chromosomal changes per generation. Physical isolation and analysis of several chromosome I size variants of one of these strains revealed that they differed only in their subtelomeric regions, leaving the central 150 Kb unaltered. Fine mapping of these subtelomeric variable regions revealed gross alterations of two very similar loci, FLO1 and FLO9. These loci are located on the right and left arms, respectively, of chromosome I and encompass internal repetitive DNA sequences. Furthermore, some chromosome I variants lacking the FLO1 locus showed evidence of recombination at a DNA region on their right arm that is enriched in repeated sequences, including Ty LTRs. We propose that repetitive sequences in many subtelomeric regions in S. cerevisiae play a key role in karyotype hypervariability. As these regions encode several membrane-associated proteins, subtelomeric plasticity may allow rapid adaptive changes of the yeast strain to specific substrates. This pattern of semi-conservative chromosomal rearrangement may have profound implications, both in terms of evolution of wild strains and for biotechnological processes.
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MESH Headings
- Blotting, Southern
- Chromosome Mapping
- Chromosomes, Fungal/chemistry
- Chromosomes, Fungal/genetics
- Chromosomes, Fungal/physiology
- DNA, Fungal/chemistry
- DNA, Fungal/genetics
- Electrophoresis, Gel, Pulsed-Field
- Evolution, Molecular
- Genetic Variation/genetics
- Genetic Variation/physiology
- Karyotyping
- Nucleic Acid Hybridization
- Oligonucleotide Array Sequence Analysis
- Polymerase Chain Reaction
- Recombination, Genetic/genetics
- Recombination, Genetic/physiology
- Repetitive Sequences, Nucleic Acid/genetics
- Repetitive Sequences, Nucleic Acid/physiology
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/physiology
- Sequence Analysis, DNA
- Telomere/genetics
- Telomere/physiology
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Affiliation(s)
- David Carro
- Institut de Biologia Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Jordi Girona 18, 08034 Barcelona, Spain
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24
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Hirzmann J, Hintz M, Kasper M, Shresta TR, Taubert A, Conraths FJ, Geyer R, Stirm S, Zahner H, Hobom G. Cloning and expression analysis of two mucin-like genes encoding microfilarial sheath surface proteins of the parasitic nematodes Brugia and Litomosoides. J Biol Chem 2002; 277:47603-12. [PMID: 12356773 DOI: 10.1074/jbc.m205770200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In several filarial genera the first stage larvae (microfilariae) are enclosed by an eggshell-derived sheath that provides a major interface between the parasite and the host immune system. Analysis of the polypeptide constituents of the microfilarial sheath from the cotton rat filaria Litomosoides sigmodontis identified two abundant surface glycoproteins: Shp3a and Shp3. The corresponding genes and the orthologues of the human parasite Brugia malayi and the rodent filaria Brugia pahangi were cloned and sequenced. They encode secreted, mucin-like proteins with N-terminal Ser/Thr-rich repeats and a C-terminal anchor domain rich in aromatic amino acids. About 75% of the protein molecular masses result from post-translational modifications. The Ser/Thr-rich motifs are supposed to serve as targets for dimethylaminoethanol-phosphate substitutions. These modifications were detected only on the sheaths of the late developmental stage of stretched microfilariae, corresponding with the expression of the proteins in the epithelium of the distal part of the uterus and the specific transcription of shp3 and shp3a in the anterior female worm segment. Genomic analysis of all three species demonstrated a conserved linkage of the two genes. Their transcripts undergo cis- and trans-splicing. The transcription start sites of the primary transcripts were determined for the L. sigmodontis genes. The core promoter regions are remarkably conserved between the paralogue genes Ls-shp3a and Ls-shp3 and their orthologues in Brugia, implicating conserved regulatory elements.
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MESH Headings
- Amino Acid Motifs
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Blotting, Southern
- Brugia malayi/metabolism
- Brugia pahangi/metabolism
- Carbohydrates/chemistry
- Chromatography, Gas
- Cloning, Molecular
- DNA, Complementary/metabolism
- Female
- Filarioidea/metabolism
- Male
- Models, Genetic
- Molecular Sequence Data
- Monosaccharides/chemistry
- Mucins/chemistry
- Mucins/genetics
- Mucins/metabolism
- Promoter Regions, Genetic
- Protein Structure, Tertiary
- RNA/metabolism
- Rats
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Amino Acid
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Transcription, Genetic
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25
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Agüero F, Campo V, Cremona L, Jäger A, Di Noia JM, Overath P, Sánchez DO, Frasch AC. Gene discovery in the freshwater fish parasite Trypanosoma carassii: identification of trans-sialidase-like and mucin-like genes. Infect Immun 2002; 70:7140-4. [PMID: 12438397 PMCID: PMC133043 DOI: 10.1128/iai.70.12.7140-7144.2002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2002] [Revised: 07/27/2002] [Accepted: 09/08/2002] [Indexed: 11/20/2022] Open
Abstract
A total of 1,921 expressed sequence tags (ESTs) were obtained from bloodstream trypomastigotes of Trypanosoma carassii, a parasite of economic importance due to its high prevalence in fish farms. Analysis of the data set allowed us to identify a trans-sialidase (TS)-like gene and three ESTs coding for putative mucin-like genes. TS activity was detected in cell extracts of bloodstream trypomastigotes. We have also used the sequence information obtained to identify genes that have not been previously described in trypanosomatids. (Additional information on these ESTs can be found at http://genoma.unsam.edu.ar/projects/tca.)
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Affiliation(s)
- Fernán Agüero
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, Universidad Nacional de General San Martín-CONICET, San Martín, 1650 Buenos Aires, Argentina
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26
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Di Noia JM, Buscaglia CA, De Marchi CR, Almeida IC, Frasch ACC. A Trypanosoma cruzi small surface molecule provides the first immunological evidence that Chagas' disease is due to a single parasite lineage. J Exp Med 2002; 195:401-13. [PMID: 11854354 PMCID: PMC2193624 DOI: 10.1084/jem.20011433] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Chagas' disease is a major health and economic problem caused by the protozoan Trypanosoma cruzi. Multiple independently evolving clones define a complex parasite population that can be arranged into two broad genetic lineages termed T. cruzi I and II. These lineages have different evolutionary origin and display distinct ecological and biological traits. Here we describe a novel molecule termed TSSA for trypomastigote small surface antigen that provides the first immunological marker allowing discrimination between lineages. TSSA is a surface, glycosylphosphatidyl inositol (GPI)-anchored mucin-like protein, highly antigenic during the infection. TSSA sequences from different parasite isolates reveal a population dimorphism that perfectly matches with the two T. cruzi lineages. Interestingly, this dimorphism is restricted to the central region of the molecule, which comprises the immunodominant B cell epitopes. This sequence variability has a major impact on TSSA antigenicity, leading to no immunological cross-reactivity between both isoforms for antibodies present either in immunization or infection sera. Furthermore, the absolute seroprevalence for TSSA in confirmed Chagasic patients is restricted to T. cruzi II isoform, strongly suggesting that human infections are due to this particular subgroup. Even though association of T. cruzi II with Chagas' disease has been proposed based on molecular markers, this is the first immunological evidence supporting this hypothesis. The implications of these results for the future research on Chagas' disease could be envisaged.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, Protozoan/chemistry
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Antigens, Surface/chemistry
- Antigens, Surface/genetics
- Antigens, Surface/immunology
- Argentina
- Base Sequence
- Blotting, Western
- Brazil
- Chagas Disease/epidemiology
- Chagas Disease/immunology
- Chagas Disease/parasitology
- Chile
- Cloning, Molecular
- Enzyme-Linked Immunosorbent Assay
- Epitopes, B-Lymphocyte/chemistry
- Epitopes, B-Lymphocyte/immunology
- Gene Expression Regulation
- Genes, Protozoan/genetics
- Humans
- Immune Sera/immunology
- Mice
- Molecular Sequence Data
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rabbits
- Rats
- Sequence Homology, Amino Acid
- Trypanosoma cruzi/chemistry
- Trypanosoma cruzi/classification
- Trypanosoma cruzi/genetics
- Trypanosoma cruzi/immunology
- Variant Surface Glycoproteins, Trypanosoma
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Affiliation(s)
- Javier M Di Noia
- Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de General San Martín/CONICET, Av. General Paz y Albarellos, San Martin, 1650 Buenos Aires, Argentina
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27
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Vitt UA, Hsu SY, Hsueh AJ. Evolution and classification of cystine knot-containing hormones and related extracellular signaling molecules. Mol Endocrinol 2001; 15:681-94. [PMID: 11328851 DOI: 10.1210/mend.15.5.0639] [Citation(s) in RCA: 184] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The cystine knot three-dimensional structure is found in many extracellular molecules and is conserved among divergent species. The identification of proteins with a cystine knot structure is difficult by commonly used pairwise alignments because the sequence homology among these proteins is low. Taking advantage of complete genome sequences in diverse organisms, we used a complementary approach of pattern searches and pairwise alignments to screen the predicted protein sequences of five model species (human, fly, worm, slime mold, and yeast) and retrieved proteins with low sequence homology but containing a typical cystine knot signature. Sequence comparison between proteins known to have a cystine knot three-dimensional structure (transforming growth factor-beta, glycoprotein hormone, and platelet-derived growth factor subfamily members) identified new crucial amino acid residues (two hydrophilic amino acid residues flanking cysteine 5 of the cystine knot). In addition to the well known members of the cystine knot superfamily, novel subfamilies of proteins (mucins, norrie disease protein, von Willebrand factor, bone morphogenetic protein antagonists, and slit-like proteins) were identified as putative cystine knot-containing proteins. Phylogenetic analysis revealed the ancient evolution of these proteins and the relationship between hormones [e.g. transforming growth factor-beta (TGFbeta)] and extracellular matrix proteins (e.g. mucins). They are absent in the unicellular yeast genome but present in nematode, fly, and higher species, indicating that the cystine knot structure evolved in extracellular signaling molecules of multicellular organisms. All data retrieved by this study can be viewed at http://hormone.stanford.edu/.
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Affiliation(s)
- U A Vitt
- Division of Reproductive Biology Department of Gynecology and Obstetrics Stanford University School of Medicine Stanford, California 94305-5317, USA.
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28
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Colli W, Alves MJ. Relevant glycoconjugates on the surface of Trypanosoma cruzi. Mem Inst Oswaldo Cruz 2000; 94 Suppl 1:37-49. [PMID: 10677690 DOI: 10.1590/s0074-02761999000700004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- W Colli
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, Brazil.
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29
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Almeida IC, Gazzinelli R, Ferguson MA, Travassos LR. Trypanosoma cruzi mucins: potential functions of a complex structure. Mem Inst Oswaldo Cruz 2000; 94 Suppl 1:173-6. [PMID: 10677709 DOI: 10.1590/s0074-02761999000700023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- I C Almeida
- Departamento de Parasitologia, ICB2, Universidade de São Paulo, Brasil.
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30
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Pollevick GD, Di Noia JM, Salto ML, Lima C, Leguizamón MS, de Lederkremer RM, Frasch AC. Trypanosoma cruzi surface mucins with exposed variant epitopes. J Biol Chem 2000; 275:27671-80. [PMID: 10843987 DOI: 10.1074/jbc.m000253200] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The protozoan parasite Trypanosoma cruzi, the agent of Chagas disease, has a large number of mucin molecules on its surface, whose expression is regulated during the life cycle. These mucins are the main acceptors of sialic acid, a monosaccharide that is required by the parasite to infect and survive in the mammalian host. A large mucin-like gene family named TcMUC containing about 500 members has been identified previously in T. cruzi. TcMUC can be divided into two subfamilies according to the presence or absence of tandem repeats in the central region of the genes. In this work, T. cruzi parasites were transfected with one tagged member of each subfamily. Only the product from the gene with repeats was highly O-glycosylated in vivo. The O-linked oligosaccharides consisted mainly of beta-d-Galp(1-->4)GlcNAc and beta-d-Galp(1-->4)[beta-d-Galp(1-->6)]-d-GlcNAc. The same glycosyl moieties were found in endogenous mucins. The mature product was anchored by glycosylphosphatidylinositol to the plasma membrane and exposed to the medium. Sera from infected mice recognized the recombinant product of one repeats-containing gene thus showing that they are expressed during the infection. TcMUC genes encode a hypervariable region at the N terminus. We now show that the hypervariable region is indeed present in the exposed mature N termini of the mucins because sera from infected hosts recognized peptides having sequences from this region. The results are discussed in comparison with the mucins from the insect stages of the parasite (Di Noia, J. M., D'Orso, I., Sánchez, D. O., and Frasch, A. C. C. (2000) J. Biol. Chem. 275, 10218-10227) which do not have variable regions.
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Affiliation(s)
- G D Pollevick
- Instituto de Investigaciones Biotecnológicas, Instituto Tecnológico de Chascomús (CONICET), Universidad Nacional de General San Martin, Av. Gral. Paz s/n, INTI, Edificio 24, 1650, San Martin, Pcia. de Buenos Aires, Argentina
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Marin F, Corstjens P, de Gaulejac B, de Vrind-De Jong E, Westbroek P. Mucins and molluscan calcification. Molecular characterization of mucoperlin, a novel mucin-like protein from the nacreous shell layer of the fan mussel Pinna nobilis (Bivalvia, pteriomorphia). J Biol Chem 2000; 275:20667-75. [PMID: 10770949 DOI: 10.1074/jbc.m003006200] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A cDNA expression library constructed from mantle tissue mRNA of the Mediterranean fan mussel Pinna nobilis was screened with antibodies raised against the acetic acid-soluble shell matrix of the same species. This resulted in the isolation of a 2138-base pair cDNA, containing 13 tandem repeats of 93 base pairs. The deduced protein has a molecular mass of 66.7 kDa and a isoelectric point of 4.8. This protein, which is enriched in serine and proline residues, was overexpressed, purified, and used for producing polyclonal antibodies. Immunological in situ and in vitro tests showed that the protein is localized in the nacreous aragonitic layer of P. nobilis, but not in the calcitic prisms. Because this protein of the nacre of P. nobilis exhibits some mucin-like characteristics, we propose the name mucoperlin. This is the first paper reporting the cloning of a molluscan mucin and the first molecular evidence for the involvement of a mucin in molluscan calcification. This finding corroborates our previous hypothesis that some of the proteinaceous constituents of the molluscan shell matrix would derive from mucins, common to many metazoan lineages of the late Precambrian (Marin, F., Smith, M., Isa, Y., Muyzer, G. and Westbroek, P. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 1554-1559). The adaptation of an ancestral mucin to a new function, the regulation of the mineralization process, may be one of the molecular events, among others, that would explain the simultaneous emergence of organized calcification in many metazoan lineages during the Cambrian explosion.
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Affiliation(s)
- F Marin
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
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Frasch AC. Functional diversity in the trans-sialidase and mucin families in Trypanosoma cruzi. PARASITOLOGY TODAY (PERSONAL ED.) 2000; 16:282-6. [PMID: 10858646 DOI: 10.1016/s0169-4758(00)01698-7] [Citation(s) in RCA: 231] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Trypanosomes are unable to synthesize the monosaccharide sialic acid, but some African trypanosomes and the American Trypanosoma cruzi can incorporate sialic acid derived from the host. To do so, T. cruzi expresses a trans-sialidase, an enzyme that catalyzes the transfer of sialic acid from host glycoconjugates to mucin-like molecules located on the parasite surface membrane. The importance of the process is indicated by the fact that T. cruzi has hundreds of genes encoding trans-sialidase, trans-sialidase-like proteins and mucin core proteins. Sequence divergence of members of these families has resulted in some molecules having functions unrelated to the acquisition of sialic acid. In this article, Alberto Frasch reviews the structure and possible function of the proteins making up these families.
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Affiliation(s)
- A C Frasch
- Instituto de Investigaciones Biotecnologicas, Universidad Nacional de General San Martin, CC30, San Martin, Buenos Aires, Argentina.
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Di Noia JM, D'Orso I, Sánchez DO, Frasch AC. AU-rich elements in the 3'-untranslated region of a new mucin-type gene family of Trypanosoma cruzi confers mRNA instability and modulates translation efficiency. J Biol Chem 2000; 275:10218-27. [PMID: 10744707 DOI: 10.1074/jbc.275.14.10218] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Trypanosoma cruzi has a complex mucin gene family of 500 members with hypervariable regions expressed preferentially in vertebrate associated stages of the parasite. In this work, a novel mucin-type gene family is reported, composed of two groups of genes organized in independent tandems and having very short open reading frames. The structures of deduced proteins share the N and C termini but differ in central regions. One group has repeats with the consensus Lys-Asn-Thr(7)-Ser-Thr(3)-Ser(Ser/Lys)-Ala-Pro and the other a Thr-rich sequence of the type Asp-Gln-Thr(17-20)-Asn-Ala-Pro-Ala-Lys-Asp-Thr(5-7)-Asn-Ala-Pro-Ala-L ys. In both cases, expected mature core proteins are around 7 kDa. Both groups, named L and S, respectively, differ in the structure of genomic loci and mRNA, with differential blocks in the 3'-untranslated region. The highest mRNA level for S and L groups are in the epimastigote stage but they show distinct developmentally regulated patterns. Transcripts are short lived and their steady-state abundance is regulated post-transcriptionally with increased mRNA stability in insect stage epimastigote. AU-rich sequences, similar to ARE motives known to cause mRNA instability in higher eukaryotes, are present in the 3'-untranslated region of the transcripts. In transfection experiments this sequence is shown to be functional for the L group destabilizing its mRNA in a stage-specific manner. Furthermore, an effect of this AU-rich region on translation efficiency is shown. To our knowledge, this is the first time that a functional ARE sequence-dependent post-transcriptional regulation mechanism is reported in a lower eukaryote.
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Affiliation(s)
- J M Di Noia
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de General San Martín, C.C. 30, 1650 San Martín, Pcia. de Buenos Aires, Argentina
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Shen Z, Dimopoulos G, Kafatos FC, Jacobs-Lorena M. A cell surface mucin specifically expressed in the midgut of the malaria mosquito Anopheles gambiae. Proc Natl Acad Sci U S A 1999; 96:5610-5. [PMID: 10318932 PMCID: PMC21908 DOI: 10.1073/pnas.96.10.5610] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An invertebrate intestinal mucin gene, AgMuc1, was isolated from the malaria vector mosquito Anopheles gambiae. The predicted 122-residue protein consists of a central core of seven repeating TTTTVAP motifs flanked by hydrophobic N- and C-terminal domains. This structure is similar to that of mucins that coat the protozoan parasite Trypanosoma cruzi. Northern blot analysis indicated that the gene is expressed exclusively in the midgut of adult mosquitoes. A length polymorphism and in situ hybridization were used to genetically and cytogenetically map AgMuc1 to division 7A of the right arm of the second chromosome. The subcellular localization of the encoded protein in tissue culture cells was examined by using a baculovirus vector to express AgMuc1 protein tagged with the green fluorescent protein (GFP). The results indicated that this protein is found at the cell surface and that both hydrophobic domains are required for cell surface targeting. We propose that AgMuc1 is an abundant mucin-like protein that lines the surface of the midgut microvilli, potentially protecting the intestinal epithelium from the proteinase-rich environment of the gut lumen. An intriguing possibility is that, as an abundant surface protein, AgMuc1 may also interact with the malaria parasite during its invasion of the mosquito midgut.
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Affiliation(s)
- Z Shen
- Department of Genetics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106-4955, USA
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Abuin G, Freitas-Junior LH, Colli W, Alves MJ, Schenkman S. Expression of trans-sialidase and 85-kDa glycoprotein genes in Trypanosoma cruzi is differentially regulated at the post-transcriptional level by labile protein factors. J Biol Chem 1999; 274:13041-7. [PMID: 10224055 DOI: 10.1074/jbc.274.19.13041] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To adapt to different environments, Trypanosoma cruzi, the protozoan parasite that causes Chagas' disease, expresses a different set of proteins during development. To begin to understand the mechanism that controls this differential gene expression, we have analyzed the levels of amastin and trans-sialidase mRNAs and the mRNAs encoding members of the 85-kDa glycoprotein gene family, which are differentially expressed in the T. cruzi stages found in the mammalian host. Amastin mRNA is expressed predominantly in intracellular and proliferative amastigotes. trans-Sialidase mRNAs are found mostly in forms undergoing transformation from amastigotes to trypomastigotes inside infected cells, whereas mRNAs encoding the 85-kDa glycoproteins appear only in the infective trypomastigotes released from the cells. The genes coding for these mRNA species are constitutively transcribed in all stages of T. cruzi cells, suggesting that expression is controlled post-transcriptionally during differentiation. Inhibition of transcription by actinomycin D revealed that each mRNA species has a relatively long half-life in stages where it accumulates. In the case of the trans-sialidase and 85-kDa glycoprotein genes, mRNA accumulation was induced by treatment with the protein synthesis inhibitor cycloheximide at the stages that preceded the normal accumulation. Therefore, mRNA stabilization may account for mRNA accumulation. mRNA degradation could be promoted by proteins with high turnover, or stabilization could be promoted by forming a complex with the translational machinery at defined times in development. Identification of the factors that induce mRNA degradation or stabilization is essential to the understanding of control of gene expression in these organisms.
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Affiliation(s)
- G Abuin
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, R. Botucatu 862 8o A, 04023-062 São Paulo, São Paulo, Brasil
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36
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Verdun RE, Di Paolo N, Urmenyi TP, Rondinelli E, Frasch AC, Sanchez DO. Gene discovery through expressed sequence Tag sequencing in Trypanosoma cruzi. Infect Immun 1998; 66:5393-8. [PMID: 9784549 PMCID: PMC108675 DOI: 10.1128/iai.66.11.5393-5398.1998] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Analysis of expressed sequence tags (ESTs) constitutes a useful approach for gene identification that, in the case of human pathogens, might result in the identification of new targets for chemotherapy and vaccine development. As part of the Trypanosoma cruzi genome project, we have partially sequenced the 5' ends of 1, 949 clones to generate ESTs. The clones were randomly selected from a normalized CL Brener epimastigote cDNA library. A total of 14.6% of the clones were homologous to previously identified T. cruzi genes, while 18.4% had significant matches to genes from other organisms in the database. A total of 67% of the ESTs had no matches in the database, and thus, some of them might be T. cruzi-specific genes. Functional groups of those sequences with matches in the database were constructed according to their putative biological functions. The two largest categories were protein synthesis (23.3%) and cell surface molecules (10.8%). The information reported in this paper should be useful for researchers in the field to analyze genes and proteins of their own interest.
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Affiliation(s)
- R E Verdun
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de General San Martín, Buenos Aires, Argentina
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37
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Previato JO, Sola-Penna M, Agrellos OA, Jones C, Oeltmann T, Travassos LR, Mendonça-Previato L. Biosynthesis of O-N-acetylglucosamine-linked glycans in Trypanosoma cruzi. Characterization of the novel uridine diphospho-N-acetylglucosamine:polypeptide N-acetylglucosaminyltransferase-catalyzing formation of N-acetylglucosamine alpha1-->O-threonine. J Biol Chem 1998; 273:14982-8. [PMID: 9614105 DOI: 10.1074/jbc.273.24.14982] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this study, we have characterized the activity of a uridine diphospho-N-acetylglucosamine:polypeptide-alpha-N-acetylglucosaminylt ransferase (O-alpha-GlcNAc-transferase) from Trypanosoma cruzi. The activity is present in microsomal membranes and is responsible for the addition of O-linked alpha-N-acetylglucosamine to cell surface proteins. This preparation adds N-acetylglucosamine to a synthetic peptide KPPTTTTTTTTKPP containing the consensus threonine-rich dodecapeptide encoded by T. cruzi MUC gene (Di Noia, J. M., Sánchez D. O., and Frasch, A. C. C. (1995) J. Biol. Chem. 270, 24146-24149). Incorporation of N-[3H]acetylglucosamine is linearly dependent on incubation time and concentration of enzyme and substrate. The transferase activity has an optimal pH of 7.5- 8.5, requires Mn2+, is unaffected by tunicamycin or amphomycin, and is strongly inhibited by UDP. The optimized synthetic peptide acceptor for the cytosolic O-GlcNAc-transferase (YSDSPSTST) (Haltiwanger, R. S., Holt, G. D., and Hart, G. W. (1990) J. Biol. Chem. 265, 2563-2568) is not a substrate for this enzyme. The glycosylated KPPTTTTTTTTKPP product is susceptible to base-catalyzed beta-elimination, and the presence of N-acetylglucosamine alpha-linked to threonine is supported by enzymatic digestion and nuclear magnetic resonance data. These results describe a unique biosynthetic pathway for T. cruzi surface mucin-like molecules, with potential chemotherapeutic implications.
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Affiliation(s)
- J O Previato
- Instituto de Microbiologia, CCS-Bloco I, Universidade Federal do Rio de Janeiro, 21944 970 Cidade Universitária, Rio de Janeiro-RJ, Brazil
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38
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Freitas-Junior LH, Briones MR, Schenkman S. Two distinct groups of mucin-like genes are differentially expressed in the developmental stages of Trypanosoma cruzi. Mol Biochem Parasitol 1998; 93:101-14. [PMID: 9662032 DOI: 10.1016/s0166-6851(98)00025-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sialic acid acceptors of Trypanosoma cruzi are abundant mucin-like glycoproteins linked to the parasite membrane by a glycosylphosphatidyl inositol (GPI) anchor. They are heterogeneous and variable in different parasite stages. The protein portion of these mucins contains many threonine residues, and is thought to be encoded by a heterogeneous gene family. To investigate whether the high degree of heterogeneity in the mucin gene family is responsible for the diversity of mucins expressed on the parasite surface, we have studied the expression of mucin genes in several developmental stages of T. cruzi. We have found that mucins are expressed in all parasite stages. By using conserved sequences at 3' end of translated sequences of the gene family and the splice leader sequence, we have isolated 120 mucin-like cDNAs by RT-PCR from epimastigote and trypomastigote mRNAs. All transcribed genes contain conserved 5' and 3' regions, which code for the signal peptide, the sequence for GPI anchor addition, and a conserved domain rich in threonine residues. The internal portions of these genes are highly variable in size and sequence, and can be grouped in two major categories. One group contains KP(1-2)T(6-8) repeats, a motif found in mammalian mucins in the central region. This group is expressed preferentially in the trypomastigote forms ready to be released from the infected mammalian cell. The other has highly variable sequences in the central portion, and is expressed in all parasite stages. Because the number of synonymous substitutions is equivalent to the non-synonymous substitutions in the second group, they are probably evolving neutrally. On the other hand, the KP(1-2)T(6-8) containing genes have more synonymous substitutions and are most likely under a strong selective pressure. We propose that the group of KP(1-2)T(6-8) motif corresponds to the highly glycosylated mucins of the trypomastigote stages. In the other group proteolysis may remove the central domain yielding small mucins, such as the mucins found in insect derived stages of T. cruzi.
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Affiliation(s)
- L H Freitas-Junior
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, UNIFESP, São Paulo, SP, Brazil
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39
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Di Noia JM, D'Orso I, Aslund L, Sánchez DO, Frasch AC. The Trypanosoma cruzi mucin family is transcribed from hundreds of genes having hypervariable regions. J Biol Chem 1998; 273:10843-50. [PMID: 9556557 DOI: 10.1074/jbc.273.18.10843] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In previous works we have identified genes in the protozoan parasite Trypanosoma cruzi whose structure resemble those of mammalian mucin genes. Indirect evidence suggested that these genes might encode the core protein of parasite mucins, glycoproteins that were proposed to be involved in the interaction with, and invasion of, mammalian host cells. We now show that the mucin gene family from T. cruzi is much larger and diverse than expected. A minimal number of 484 mucin genes per haploid genome is calculated for a parasite clone. Most, if not all, genes are transcribed, as deduced from cDNA analysis. Comparison of the cDNA sequences showed evidences of a high mutation rate in localized regions of the genes. Sequence conservation among members of the family is much higher in the untranslated (UTR) regions than in the sequences encoding the mature mucin core protein. Transcription units can be classified into two main subfamilies according to the sequence homologies in the 5'-UTR, whereas the 3'-UTR is highly conserved in all clones analyzed. The common origin of members of this gene family as well as their relationships can be defined by sequence comparison of different domains in the transcription units. The regions encoding the N and C termini, supposed to correspond to the leader peptide and membrane-anchoring signal, respectively, (Di Noia, J. M., Sánchez, D. O., and Frasch, A. C. C. (1995) J. Biol. Chem. 270, 24146-24149) are highly conserved. Conversely, the central regions are highly variable. These regions encode the target sites for O-glycosylation and are made of a variable number of repetitive units rich in Thr and Pro residues or are nonrepetitive but still rich in Thr/Ser and Pro residues. The region putatively coding for the N-terminal domain of the mature core protein is hypervariable, being different in most of the transcripts sequenced. Nonrepetitive central domains are unique to each gene. Gene-specific probes show that the relative abundance of different mRNAs varies greatly within the same parasite clone.
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Affiliation(s)
- J M Di Noia
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de General San Martín, Casilla de Correo 30, 1650, Provincia de Buenos Aires, Argentina
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40
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Ferguson MA. The surface glycoconjugates of trypanosomatid parasites. Philos Trans R Soc Lond B Biol Sci 1997; 352:1295-302. [PMID: 9355120 PMCID: PMC1692025 DOI: 10.1098/rstb.1997.0113] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Insect-transmitted protozoan parasites of the order Kinetoplastida, suborder Trypanosomatina, include Trypanosoma brucei (aetiological agent of African sleeping sickness), Trypanosoma cruzi (aetiological agent of Chagas' disease in South and Central America) and Leishmania spp. (aetiological agents of a variety of diseases throughout the tropics and sub-tropics). The structures of the most abundant cell-surface molecules of these organisms is reviewed and correlated with the different modes of parasitism of the three groups of parasites. The major surface molecules are all glycosylphosphatidylinositol (GPI)-anchored glycoproteins, such as the variant surface glycoproteins of T. brucei and the surface mucins of T. cruzi, or complex glycophospholipids, such as the lipophosphoglycans and glycoinositolphospholipids of the leishmanias. Significantly, all of the aforementioned structures share a motif of Man alpha 1-4GlcN alpha 1-6-myo-inositol-1-HPO4-lipid and can therefore be considered to be members of a GPI superfamily.
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Affiliation(s)
- M A Ferguson
- Department of Biochemistry, University of Dundee, UK
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41
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Wang P, Granados RR. Molecular cloning and sequencing of a novel invertebrate intestinal mucin cDNA. J Biol Chem 1997; 272:16663-9. [PMID: 9195982 DOI: 10.1074/jbc.272.26.16663] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The first invertebrate intestinal mucin, termed insect intestinal mucin (IIM), was recently identified from Trichoplusia ni larvae (Wang, P., and Granados, R. R. (1997) Proc. Natl. Acad. Sci. U. S. A. , in press). We report the cDNA cloning and sequencing of IIM, which is only the second completely sequenced intestinal mucin after human intestinal mucin, MUC2. To clone and sequence the cDNA for IIM, a T. ni larval midgut cDNA expression library was constructed and screened with an anti-IIM antiserum. Two full-length cDNA clones for IIM were identified and sequenced. The deduced proteins from the two cDNA clones contained 807 and 788 amino acid residues, respectively. The structural organization of IIM is similar to that of MUC2, containing a 25-amino acid signal leading sequence and two threonine/proline/alanine-rich tandem repeat domains flanked by cysteine-rich sequences. One tandem repeat domain contained two repeating units, TTTQAP and AATTP, and the other contained one repeating unit, TAAP. The cysteine-rich regions showed potential chitin binding features. By immunolocalization in tissue sections, it was determined that IIM is expressed in midgut tissues. The IIM mRNA is abundant in the midgut tissue, and Northern blot analysis indicated that IIM transcripts were not polydispersed as is found in mammalian mucin transcription.
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Affiliation(s)
- P Wang
- Department of Entomology, Cornell University, Ithaca, New York 14853, USA
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42
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Wang P, Granados RR. An intestinal mucin is the target substrate for a baculovirus enhancin. Proc Natl Acad Sci U S A 1997; 94:6977-82. [PMID: 9192677 PMCID: PMC21270 DOI: 10.1073/pnas.94.13.6977] [Citation(s) in RCA: 181] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
An invertebrate intestinal mucin (IIM) was identified from a lepidopterous insect, Trichoplusia ni. The IIM is a major protein constituent of the peritrophic membrane that facilitates the digestive process, as well as protecting invertebrate digestive tracts from microbial infections. The IIM demonstrated biochemical characteristics similar to vertebrate mucins, but exhibited strong association with the chitin-containing peritrophic membrane matrix. We have demonstrated that a baculovirus enhancin, which is encoded and carried by specific baculoviruses, has mucin-degrading activity both in vitro and in vivo. The in vivo degradation of IIM by enhancin was correlated with the enhancement of baculovirus infections in insects. These findings have shown that viruses have evolved a novel strategy to overcome intestinal mucinous barriers against microorganisms by utilizing a mucin-degrading enzyme.
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Affiliation(s)
- P Wang
- Department of Entomology, Cornell University, Ithaca, NY 14853, USA
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43
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Di Noia JM, Pollevick GD, Xavier MT, Previato JO, Mendoça-Previato L, Sánchez DO, Frasch AC. High diversity in mucin genes and mucin molecules in Trypanosoma cruzi. J Biol Chem 1996; 271:32078-83. [PMID: 8943259 DOI: 10.1074/jbc.271.50.32078] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Mucins are highly O-glycosylated molecules which in mammalian cells accomplish essential functions, like cytoprotection and cell-cell interactions. In the protozoan parasite Trypanosoma cruzi, mucin-related glycoproteins have been shown to play a relevant role in the interaction with and invasion of host cells. We have previously reported a family of mucin-like genes in T. cruzi whose overall structure resembled that of mammalian mucin genes. We have now analyzed the relationship between these genes and mucin proteins. A monoclonal antibody specific for a mucin sugar epitope and a polyclonal serum directed to peptide epitopes in a MUC gene-encoded recombinant protein, detected identical bands in three out of seven strains of T. cruzi. Immunoprecipitation experiments confirmed these results. When expressed in eukaryotic cells, the MUC gene product is post-translationally modified, most likely, through extensive O-glycosylation. Gene sequencing showed that the central domains encoding the repeated sequences with the consensus T8KP2, varies in number from 1 to 10, and the number of Thr residues in each repeat could be 7, 8, or 10. A run of 16 to 18 Thr residues was present in some, but not all, MUC gene-derived sequences. Direct compositional analysis of mucin core proteins showed that Thr residues are much more frequent than Ser residues. The same fact occurs in MUC gene-derived protein sequences. Molecular mass determinations of the 35-kDa glycoproteins further extend the heterogeneity of the family to the natural mucin molecules. Difficulties in assigning each of the several MUC genes identified to a mucin product arise from the high diversity and partial sequence conservation of the members of this family.
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Affiliation(s)
- J M Di Noia
- Instituto de Investigaciones Bioquímicas, "Fundación Campomar," Antonio Machado 151, and Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1405 Buenos Aires, Argentina
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44
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Wiese M, Berger O, Stierhof YD, Wolfram M, Fuchs M, Overath P. Gene cloning and cellular localization of a membrane-bound acid phosphatase of Leishmania mexicana. Mol Biochem Parasitol 1996; 82:153-65. [PMID: 8946382 DOI: 10.1016/0166-6851(96)02729-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In a previous publication, we described the purification of a membrane-bound acid phosphatase of Leishmania mexicana as a heterogeneously N-glycosylated protein of an apparent molecular mass of 70000-72000 expressed in both the promastigote and the amastigote stage of the parasite [19]. Screening of a genomic DNA library of L. mexicana with degenerate oligonucleotides designed according to the NH2-terminus of the protein led to the cloning of the lmmbap gene, which is present in one copy per haploid genome. The open reading frame predicts a protein of 516 amino acids composed of a signal sequence, a large hydrophilic region, a trans-membrane alpha-helix and a short cytoplasmic tail. The sequence of the hydrophilic region is homologous to acid phosphatases from other organisms. While in wild-type promastigotes, the acid phosphatase is located in the endosomal/lysosomal compartment between the flagellar pocket and the nucleus, overexpression leads to its abundant exposure on the cell surface. In cells transfected with a construct lacking the region corresponding to the trans-membrane and the cytoplasmic parts, the resulting altered acid phosphatase is efficiently secreted into the culture medium. The potential of this system for studies on membrane trafficking in kinetoplastid organisms is discussed.
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Affiliation(s)
- M Wiese
- Max-Planck-Institut für Biologie, Abteilung Membranbiochemie, Tübingen, Germany.
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Salazar NA, Mondragon A, Kelly JM. Mucin-like glycoprotein genes are closely linked to members of the trans-sialidase super-family at multiple sites in the Trypanosoma cruzi genome. Mol Biochem Parasitol 1996; 78:127-36. [PMID: 8813683 DOI: 10.1016/s0166-6851(96)02617-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In Trypanosoma cruzi a cell surface enzyme with trans-sialidase (TS) activity has been implicated as an important factor in establishing infection. The enzyme is encoded by genes belonging to a large super-family which on the basis of sequence has been subdivided into 4 groups. TS mediates the transfer of sialic acid residues from host glycoconjugates to acceptor molecules on the parasite surface. To study the organisation of the TS genes we isolated several distinct cosmids from a library constructed with DNA from the T. cruzi X10.6 clone. In these cosmids, the TS genes (group I) were present either as single copies or as a direct tandem repeat. A common feature of the cosmids was the presence of a related group III gene located 10-12kb downstream of the TS gene(s) and arranged in the same orientation. In several of the cosmids we also identified a mucin-like glycoprotein gene located between the group I and group III genes. The mucin-like genes are part of a large polymorphic family and contour clamped homogeneous electric field electrophoresis (CHEFE) analysis showed that they were linked to members of the TS super-family at multiple sites in the X10.6 genome. Screening of a second cosmid library made with DNA from the CL-Brener clone confirmed this multiple linkage suggesting that it is a common feature of the species. This genetic organisation may have important functional significance since the mucin-like glycoproteins are the major cell surface acceptors of sialic acid.
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Affiliation(s)
- N A Salazar
- Department of Medical Parasitology, London School of Hygiene and Tropical Medicine, UK
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