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Herreros-Cabello A, Callejas-Hernández F, Gironès N, Fresno M. Trypanosoma Cruzi Genome: Organization, Multi-Gene Families, Transcription, and Biological Implications. Genes (Basel) 2020; 11:E1196. [PMID: 33066599 PMCID: PMC7602482 DOI: 10.3390/genes11101196] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 10/08/2020] [Accepted: 10/12/2020] [Indexed: 01/20/2023] Open
Abstract
Chagas disease caused by the parasite Trypanosoma cruzi affects millions of people. Although its first genome dates from 2005, its complexity hindered a complete assembly and annotation. However, the new sequencing methods have improved genome annotation of some strains elucidating the broad genetic diversity and complexity of this parasite. Here, we reviewed the genomic structure and regulation, the genetic diversity, and the analysis of the principal multi-gene families of the recent genomes for several strains. The telomeric and sub-telomeric regions are sites with high recombination events, the genome displays two different compartments, the core and the disruptive, and the genome plasticity seems to play a key role in the survival and the infection process. Trypanosoma cruzi (T. cruzi) genome is composed mainly of multi-gene families as the trans-sialidases, mucins, and mucin-associated surface proteins. Trans-sialidases are the most abundant genes in the genome and show an important role in the effectiveness of the infection and the parasite survival. Mucins and MASPs are also important glycosylated proteins of the surface of the parasite that play a major biological role in both insect and mammal-dwelling stages. Altogether, these studies confirm the complexity of T. cruzi genome revealing relevant concepts to better understand Chagas disease.
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Affiliation(s)
- Alfonso Herreros-Cabello
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (A.H.-C.); (F.C.-H.)
| | - Francisco Callejas-Hernández
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (A.H.-C.); (F.C.-H.)
| | - Núria Gironès
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (A.H.-C.); (F.C.-H.)
- Instituto Sanitario de Investigación Princesa, 28006 Madrid, Spain
| | - Manuel Fresno
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain; (A.H.-C.); (F.C.-H.)
- Instituto Sanitario de Investigación Princesa, 28006 Madrid, Spain
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2
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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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3
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Dos-Santos A, Carvalho-Kelly L, Dick C, Meyer-Fernandes J. Innate immunomodulation to trypanosomatid parasite infections. Exp Parasitol 2016; 167:67-75. [DOI: 10.1016/j.exppara.2016.05.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 05/13/2016] [Accepted: 05/21/2016] [Indexed: 01/05/2023]
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5
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Cloning, localization and differential expression of the Trypanosoma cruzi TcOGNT-2 glycosyl transferase. Gene 2012; 498:147-54. [PMID: 22387207 DOI: 10.1016/j.gene.2012.02.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 02/07/2012] [Accepted: 02/14/2012] [Indexed: 01/02/2023]
Abstract
The surface of Trypanosoma cruzi is covered by a dense glycocalix which is characteristic of each stage of the life cycle. Its composition and complexity depend mainly on mucin-like proteins. A remarkable feature of O-glycan biosynthesis in trypanosomes is that it initiates with the addition of a GlcNAc instead of the GalNAc residue that is commonly used in vertebrate mucins. The fact that the interplay between trans-sialidase and mucin is crucial for pathogenesis, and both families have stage-specific members is also remarkable. Recently the enzyme that transfers the first GlcNAc from UDP-GlcNAc to a serine or threonine residue was kinetically characterized. The relevance of this enzyme is evidenced by its role as catalyzer of the first step in O-glycosylation. In this paper we describe how this gene is expressed differentially along the life cycle with a pattern that is very similar to that of trans-sialidases. Its localization was determined, showing that the protein predicted to be in the Golgi apparatus is also present in reservosomes. Finally our results indicate that this enzyme, when overexpressed, enhances T. cruzi infectivity.
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6
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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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7
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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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8
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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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9
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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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10
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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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Doedens A, Loukas A, Maizels RM. A cDNA encoding Tc-MUC-5, a mucin from Toxocara canis larvae identified by expression screening. Acta Trop 2001; 79:211-7. [PMID: 11412804 DOI: 10.1016/s0001-706x(01)00137-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Toxocara canis is an ascarid nematode parasite of canids. Larvae infect a wide range of accidental hosts including humans, in whom they are the aetiologic agent of visceral and ocular Larva migrans. The labile surface coat of T. canis larvae consists of a family of mucin glycoproteins termed TES-120, for which the cDNAs have recently been cloned. In this paper, we describe the identification of a novel cDNA (Tc-muc-5) encoding an apomucin by expression screening of a cDNA library with antiserum raised to T. canis excretory/secretory products, and compare the predicted Tc-MUC-5 protein with those of other T. canis mucins (Tc-MUC-1-Tc-MUC-4) that include the TES-120 surface coat glycoproteins. Tc-MUC-5 has both a larger open reading frame and a more divergent sequence than the other T. canis mucins. It contains a putative signal peptide followed by two six-cysteine (SXC) domains, an extended threonine-rich central mucin core domain and two C-terminal SXC domains. Amino acid composition analysis of secreted TES-120 glycoproteins revealed a distinct lack of lysine residues; while this finding is in agreement with the primary sequences of Tc-MUC-1-Tc-MUC-4, Tc-MUC-5 is conspicuous by its relative abundance of lysines (6.7%), suggesting that this protein is not part of the TES-120 family of surface coat proteins.
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Affiliation(s)
- A Doedens
- Institute of Cell, Animal and Population Biology, University of Edinburgh, West Mains Road, EH9 3JT, Edinburgh, UK
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12
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Carmo MS, Santos MR, Cummings LM, Araya JE, Yamauchi LM, Yoshida N, Mortara RA, Franco da Silveira J. Isolation and characterisation of genomic and cDNA clones coding for a serine-, alanine-, and proline-rich protein of Trypanosoma cruzi. Int J Parasitol 2001; 31:259-64. [PMID: 11226452 DOI: 10.1016/s0020-7519(00)00170-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We report here the isolation and characterisation of genomic and cDNA clones encoding a Serine-, Alanine-, and Proline-rich protein (SAP) of Trypanosoma cruzi metacyclic trypomastigotes. The deduced peptides translated from these clones were characterised by a high content of residues of alanine, proline, serine, glycine, valine, and threonine distributed in several repeats: P(2-4), S(2-3), A(2-3), AS, SA, PA, AP, SP, PS, and TP. The repeats are partially homologous to the serine-, alanine-, and proline-containing motifs of Leishmania major and Leishmania mexicana proteophosphoglycans. Genes coding for SAP are part of a polymorphic family whose members are linked to members of gp85/sialidase and mucin-like gene families. This is consistent with the hypothesis that this genetic organisation could be a means by which T. cruzi co-ordinates the expression of major surface proteins.
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Affiliation(s)
- M S Carmo
- Escola Paulista de Medicina, UNIFESP, Departamento de Microbiologia, Imunologia e Parasitologia, R. Botucatu, 862, CEP 04023-062, S. Paulo, Brazil
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13
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Affiliation(s)
- C L Allen
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1 7HT, United Kingdom
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Elias MC, Marques-Porto R, Freymüller E, Schenkman S. Transcription rate modulation through the Trypanosoma cruzi life cycle occurs in parallel with changes in nuclear organisation. Mol Biochem Parasitol 2001; 112:79-90. [PMID: 11166389 DOI: 10.1016/s0166-6851(00)00349-2] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In trypanosomes transcription occurs as large polycistronic units, with trans-splicing and polyadenylation generating each individual mRNA. There are no defined RNA polymerase II promoters and mRNA stabilisation is most likely the process controlling levels of differentially expressed mRNAs, since no selective modulation of gene activity has even been reported at the transcriptional level. Here, we show a large decrease in the transcription rates by RNA polymerases I and II when proliferative forms of Trypanosoma cruzi (epimastigotes and amastigotes) transform into non-proliferative and infective forms (trypomastigotes). We also show that these changes in transcription occur in parallel with modifications in the nuclear structure. While nuclei of proliferative forms are round, contain small amounts of peripheral heterochromatin and a large nucleolus, nuclei of trypomastigotes are elongated, the nucleolus disappears and the heterochromatin occupies most of the nuclear compartment. The decrease in the transcription parallels the nucleolus disassembly, as seen by the dispersion of nucleolar antigens. As T. cruzi cycles continuously through proliferative and infective forms, the molecular mechanisms involved in the control of nuclear organisation and chromatin remodelling can be revealed by this system.
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Affiliation(s)
- M C Elias
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo, R. Botucatu 8628A, 04023-062 São Paulo S.P., Brazil
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15
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Málaga S, Yoshida N. Targeted reduction in expression of Trypanosoma cruzi surface glycoprotein gp90 increases parasite infectivity. Infect Immun 2001; 69:353-9. [PMID: 11119524 PMCID: PMC97890 DOI: 10.1128/iai.69.1.353-359.2001] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A previous study had shown that the expression of gp90, a stage-specific surface glycoprotein of Trypanosoma cruzi metacyclic trypomastigotes, is inversely correlated with the parasite's ability to invade mammalian cells. By using antisense oligonucleotides complementary to a region of the gp90 gene implicated in host cell adhesion, we investigated whether the selective inhibition of gp90 synthesis affected the capacity of metacyclic forms to enter target cells. Parasites were incubated for 24 h with 20 microM PS1, a phosphorothioate oligonucleotide based on a sequence of the gp90 coding strand; PS2, the antisense counterpart of PS1; or PO2, the unmodified version of PS2 containing phosphodiester linkages, and the expression of surface molecules was analyzed by flow cytometry and immunoblotting using specific monoclonal antibodies. PS2 but not PS1 or PO2 inhibited the expression of gp90. Inhibition by PS2 was dose dependent. Northern blot analysis revealed that steady-state gp90 mRNA levels were diminished in PS2-treated parasites compared to untreated controls. Treatment with PS2 did not affect the expression of other metacyclic stage surface glycoproteins involved in parasite-host cell interaction, such as gp82 and the mucin-like gp35/50. Expression of gp90 was also inhibited by other phosphorothioate oligonucleotides targeted to the gp90 gene (PS4, PS5, PS6, and PS7) but not by PS3, with the same base composition as PS2 but a mismatched sequence. Parasites treated with PS2, PS4, or PS5 entered HeLa cells in significantly higher numbers than untreated controls, whereas the invasive capacity of PS1- and PS3-treated parasites was unchanged, confirming the inverse association between infectivity and gp90 expression.
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Affiliation(s)
- S Málaga
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
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16
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Loukas A, Hintz M, Linder D, Mullin NP, Parkinson J, Tetteh KK, Maizels RM. A family of secreted mucins from the parasitic nematode Toxocara canis bears diverse mucin domains but shares similar flanking six-cysteine repeat motifs. J Biol Chem 2000; 275:39600-7. [PMID: 10950959 DOI: 10.1074/jbc.m005632200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Infective larvae of the parasitic nematode Toxocara canis secrete a family of mucin-like glycoproteins, which are implicated in parasite immune evasion. Analysis of T. canis expressed sequence tags identified a family of four mRNAs encoding distinct apomucins (Tc-muc-1-4), one of which had been previously identified in the TES-120 family of glycoproteins secreted by this parasite. The protein products of all four cDNAs contain signal peptides, a repetitive serine/threonine-rich tract, and varying numbers of 36-amino acid six-cysteine (SXC) domains. SXC domains are found in many nematode proteins and show similarity to cnidarian (sea anemone) toxins. Antibodies to the SXC domains of Tc-MUC-1 and Tc-MUC-3 recognize differently migrating members of TES-120. TES-120 proteins separated by chromatographic methods showed distinct amino acid composition, mass, and sequence information by both Edman degradation and matrix-assisted laser desorption ionization/time of flight mass spectrometry on peptide fragments. Tc-MUC-1, -2, and -3 were shown to be secreted mucins with real masses of 39.7, 47.8, and 45.0 kDa in contrast to their predicted peptide masses of 15.7, 16.2, and 26.0 kDa, respectively. The presence of SXC domains in all mucin products supports the suggestion that the SXC motif is required for mucin assembly or export. Homology modeling indicates that the six-cysteine domains of the T. canis mucins adopt a similar fold to the sea anemone potassium channel-blocking toxin BgK, forming three disulfide bonds within each subunit.
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MESH Headings
- Amino Acid Sequence
- Animals
- Blotting, Western
- Chromatography
- Chromatography, High Pressure Liquid
- Cysteine/chemistry
- DNA, Complementary/metabolism
- Electrophoresis, Polyacrylamide Gel
- Expressed Sequence Tags
- Female
- Gastric Mucins/chemistry
- Gastric Mucins/genetics
- Gene Library
- Models, Biological
- Models, Molecular
- Molecular Sequence Data
- Mucins/chemistry
- Mucins/genetics
- Multigene Family
- Protein Sorting Signals
- Protein Structure, Tertiary
- RNA, Messenger/metabolism
- Recombinant Proteins/metabolism
- Sequence Homology, Amino Acid
- Serine/chemistry
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Threonine/chemistry
- Toxocara canis/chemistry
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Affiliation(s)
- A Loukas
- Institute of Cell, Animal and Population Biology and Department of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, United Kingdom
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Hicks SJ, Theodoropoulos G, Carrington SD, Corfield AP. The role of mucins in host-parasite interactions. Part I-protozoan parasites. PARASITOLOGY TODAY (PERSONAL ED.) 2000; 16:476-81. [PMID: 11063858 DOI: 10.1016/s0169-4758(00)01773-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Parasite-derived mucin-like molecules might be involved in parasite attachment to and invasion of host cells. In addition, parasites might secrete mucin-degrading enzymes, enabling the penetration of protective mucus gels that overlie the mucosal surfaces of their potential hosts. Furthermore, they might generate binding ligands on the membrane-bound mucins of host cells by using specific glycosidases. It is possible that host mucins and mucin-like molecules prevent the establishment of parasites or facilitate parasite expulsion. They might also serve as a source of metabolic energy and adhesion ligands for those parasites adapted to exploit them. Sally Hicks and colleagues here review the biochemical properties of mucins and mucin-like molecules in relation to interactions (established and putative) between protozoan parasites and their hosts.
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Affiliation(s)
- S J Hicks
- Centre for Biomedical Sciences, School of Applied Sciences, University of Wales Institute Cardiff, Cardiff, UK.
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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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19
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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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20
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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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21
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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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Almeida IC, Camargo MM, Procópio DO, Silva LS, Mehlert A, Travassos LR, Gazzinelli RT, Ferguson MA. Highly purified glycosylphosphatidylinositols from Trypanosoma cruzi are potent proinflammatory agents. EMBO J 2000; 19:1476-85. [PMID: 10747016 PMCID: PMC310217 DOI: 10.1093/emboj/19.7.1476] [Citation(s) in RCA: 182] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Intracellular protozoan parasites are potent stimulators of cell-mediated immunity. The induction of macrophage proinflammatory cytokines by Trypanosoma cruzi is considered to be important in controlling the infection and the outcome of Chagas' disease. Here we show that the potent tumour necrosis factor-alpha-, interleukin-12- and nitric oxide-inducing activities of T.cruzi trypomastigote mucins were recovered quantitatively in a highly purified and characterized glycosylphosphatidylinositol (GPI) anchor fraction of this material. The bioactive trypomastigote GPI fraction was compared with a relatively inactive GPI fraction prepared from T. cruzi epimastigote mucins. The trypomastigote GPI structures were found to contain additional galactose residues and unsaturated, instead of saturated, fatty acids in the sn-2 position of the alkylacylglycerolipid component. The latter feature is essential for the extreme potency of the trypomastigote GPI fraction, which is at least as active as bacterial endotoxin and Mycoplasma lipopeptide and, therefore, one of the most potent microbial proinflammatory agents known.
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Affiliation(s)
- I C Almeida
- Division of Molecular Parasitology and Biological Chemistry, Department of Biochemistry, University of Dundee, Dundee DD1 5EH, UK
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Santos MR, Lorenzi H, Porcile P, Carmo MS, Schijman A, Brandão A, Araya JE, Gomes HB, Chiurillo MA, Ramirez JL, Degrave WM, Levin MJ, da Silveira JF. Physical mapping of a 670-kb region of chromosomes XVI and XVII from the human protozoan parasite Trypanosoma cruzi encompassing the genes for two immunodominant antigens. Genome Res 1999; 9:1268-76. [PMID: 10613849 PMCID: PMC311010 DOI: 10.1101/gr.9.12.1268] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
As part of the Trypanosoma cruzi Genome Initiative, we have mapped a large portion of the chromosomal bands XVI (2.3 Mb) and XVII (2.6 Mb) containing the highly repetitive and immunodominant antigenic gene families h49 and jl8. Restriction mapping of the isolated chromosomal bands and hybridization with chromosome specific gene probes showed that genes h49 and jl8 are located in a pair of size-polymorphic homologous chromosomes. To construct the integrated map of the chromosomes harboring the h49 and jl8 loci, we used YAC, cosmid, and lambda phage overlapping clones, and long range restriction analysis using a variety of probes (i.e., known gene sequences, ESTs, polymorphic repetitive sequences, anonymous sequences, STSs generated from the YAC ends). The total length covered by the YAC contig was approximately 670 kb, and its map agreed and was complementary to the one obtained by long-range restriction fragment analysis. Average genetic marker spacing in a 105 kb region around h49 and jl8 genes was estimated to be 6.2 kb/marker. We have detected some polymorphism in the H49/JL8 antigens-encoding chromosomes, affecting also the coding regions. The physical map of this region, together with the isolation of specific chromosome markers, will contribute in the global effort to sequence the nuclear genome of this parasite.
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Affiliation(s)
- M R Santos
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, UNIFESP, Rua Botucatu 862, CEP 04023-062, S. Paulo, Brasil
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