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Gui L, O'Shaughnessy WJ, Cai K, Reetz E, Reese ML, Nicastro D. Cryo-tomography reveals rigid-body motion and organization of apicomplexan invasion machinery. Nat Commun 2023; 14:1775. [PMID: 36997532 PMCID: PMC10063558 DOI: 10.1038/s41467-023-37327-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 03/10/2023] [Indexed: 04/03/2023] Open
Abstract
The apical complex is a specialized collection of cytoskeletal and secretory machinery in apicomplexan parasites, which include the pathogens that cause malaria and toxoplasmosis. Its structure and mechanism of motion are poorly understood. We used cryo-FIB-milling and cryo-electron tomography to visualize the 3D-structure of the apical complex in its protruded and retracted states. Averages of conoid-fibers revealed their polarity and unusual nine-protofilament arrangement with associated proteins connecting and likely stabilizing the fibers. Neither the structure of the conoid-fibers nor the architecture of the spiral-shaped conoid complex change during protrusion or retraction. Thus, the conoid moves as a rigid body, and is not spring-like and compressible, as previously suggested. Instead, the apical-polar-rings (APR), previously considered rigid, dilate during conoid protrusion. We identified actin-like filaments connecting the conoid and APR during protrusion, suggesting a role during conoid movements. Furthermore, our data capture the parasites in the act of secretion during conoid protrusion.
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Affiliation(s)
- Long Gui
- Department of Cell Biology, University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - William J O'Shaughnessy
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - Kai Cai
- Department of Cell Biology, University of Texas, Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - Evan Reetz
- Department of Cell Biology, University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - Michael L Reese
- Department of Pharmacology, University of Texas, Southwestern Medical Center, Dallas, TX, USA.
- Department of Biochemistry, University of Texas, Southwestern Medical Center, Dallas, TX, USA.
| | - Daniela Nicastro
- Department of Cell Biology, University of Texas, Southwestern Medical Center, Dallas, TX, USA.
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Sohn CS, Cheng TT, Drummond ML, Peng ED, Vermont SJ, Xia D, Cheng SJ, Wastling JM, Bradley PJ. Identification of novel proteins in Neospora caninum using an organelle purification and monoclonal antibody approach. PLoS One 2011; 6:e18383. [PMID: 21483743 PMCID: PMC3070720 DOI: 10.1371/journal.pone.0018383] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2010] [Accepted: 02/28/2011] [Indexed: 11/25/2022] Open
Abstract
Neospora caninum is an important veterinary pathogen that causes abortion in cattle and neuromuscular disease in dogs. Neospora has also generated substantial interest because it is an extremely close relative of the human pathogen Toxoplasma gondii, yet does not appear to infect humans. While for Toxoplasma there are a wide array of molecular tools and reagents available for experimental investigation, relatively few reagents exist for Neospora. To investigate the unique biological features of this parasite and exploit the recent sequencing of its genome, we have used an organelle isolation and monoclonal antibody approach to identify novel organellar proteins and develop a wide array of probes for subcellular localization. We raised a panel of forty-six monoclonal antibodies that detect proteins from the rhoptries, micronemes, dense granules, inner membrane complex, apicoplast, mitochondrion and parasite surface. A subset of the proteins was identified by immunoprecipitation and mass spectrometry and reveal that we have identified and localized many of the key proteins involved in invasion and host interaction in Neospora. In addition, we identified novel secretory proteins not previously studied in any apicomplexan parasite. Thus, this organellar monoclonal antibody approach not only greatly enhances the tools available for Neospora cell biology, but also identifies novel components of the unique biological characteristics of this important veterinary pathogen.
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Affiliation(s)
- Catherine S. Sohn
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
- Division of Laboratory Animal Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Tim T. Cheng
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Michael L. Drummond
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Eric D. Peng
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Sarah J. Vermont
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Dong Xia
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Stephen J. Cheng
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
| | - Jonathan M. Wastling
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Peter J. Bradley
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Risco-Castillo V, Fernández-García A, Zaballos A, Aguado-Martínez A, Hemphill A, Rodríguez-Bertos A, Alvarez-García G, Ortega-Mora LM. Molecular characterisation of BSR4, a novel bradyzoite-specific gene from Neospora caninum. Int J Parasitol 2007; 37:887-96. [PMID: 17376452 DOI: 10.1016/j.ijpara.2007.02.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Revised: 01/26/2007] [Accepted: 02/04/2007] [Indexed: 11/21/2022]
Abstract
Here we present the identification and cloning of the NcBSR4 gene, the putative Neospora caninum orthologue to the Toxoplasma gondii TgBSR4 gene. To isolate NcBSR4, genome walking PCR was performed on N. caninum genomic DNA using the expressed sequence tag NcEST3c28h02.y1 sequence, which shares a 44% identity with the TgBSR4 gene, as a framework. Nucleotide sequencing of amplified DNA fragments revealed a single uninterrupted 1227 bp open reading frame that encodes a protein of 408 amino acids with 66% similarity to the TgBSR4 antigen. A putative 39-residue signal peptide was found at the NH2-terminus, followed by a hydrophilic region. At the COOH-terminus, a potential site for a glycosylphosphatidylinositol anchor was identified at amino acid 379. A polyclonal serum against recombinant NcBSR4 protein was raised in rabbits, and immunolabelling demonstrated stage-specific expression of the NcBSR4 antigen in N. caninum bradyzoites produced in vitro and in vivo. Furthermore, RT-PCR analysis showed a slight increase of NcBSR4 transcripts in bradyzoites generated during in vitro tachyzoite-to-bradyzoite stage-conversion, suggesting that this gene is specifically expressed at the bradyzoite stage and that its transcription relies on the switch to this stage.
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Affiliation(s)
- V Risco-Castillo
- SALUVET. Dpto. de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain
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Fernández-García A, Risco-Castillo V, Zaballos A, Alvarez-García G, Ortega-Mora LM. Identification and molecular cloning of the Neospora caninum SAG4 gene specifically expressed at bradyzoite stage. Mol Biochem Parasitol 2005; 146:89-97. [PMID: 16303187 DOI: 10.1016/j.molbiopara.2005.08.019] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Revised: 08/18/2005] [Accepted: 08/18/2005] [Indexed: 11/25/2022]
Abstract
Here, we identify and clone the NcSAG4 gene, orthologue to the Toxoplasma gondii TgSAG4 gene, and the first reported gene to be expressed specifically during the Neospora caninum bradyzoite stage. To isolate NcSAG4, we designed degenerate oligonucleotides based on the TgSAG4 protein amino acid sequence. A 312-bp DNA fragment was amplified by PCR from N. caninum genomic DNA, whose sequence showed 65% identity to TgSAG4 gene over 257 bp. NcSAG4 gene sequence was obtained by PCR genome walking. Nucleotide sequencing of amplified DNA fragments showed a single uninterrupted 522-bp ORF that encoded a 173-amino-acid protein with a predicted molecular mass of 18,394 Da, with 69% similarity to the TgSAG4 antigen. A 28-residue putative signal peptide was found at the NH2-terminus, followed by a strongly hydrophilic region. An amino acid motif for a phosphatidylinositol glycan anchor was identified at the COOH-terminus. The NcSAG4 protein lacking the putative signal peptide at the NH2-terminus was expressed in Escherichia coli and was recognized in western blot by sera from congenitally infected cattle. A mouse polyclonal anti-rNcSAG4 serum was produced for immunofluorescence studies, and revealed stage-specific NcSAG4 antigen expression in in vitro-cultured bradyzoites. Real-time reverse transcription-PCR analysis with samples from in vitro stage-conversion assay showed increasing levels of NcSAG4 transcript over time, suggesting a developmental upregulation of this gene.
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Affiliation(s)
- A Fernández-García
- Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
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Dubey JP, Barr BC, Barta JR, Bjerkås I, Björkman C, Blagburn BL, Bowman DD, Buxton D, Ellis JT, Gottstein B, Hemphill A, Hill DE, Howe DK, Jenkins MC, Kobayashi Y, Koudela B, Marsh AE, Mattsson JG, McAllister MM, Modrý D, Omata Y, Sibley LD, Speer CA, Trees AJ, Uggla A, Upton SJ, Williams DJL, Lindsay DS. Redescription of Neospora caninum and its differentiation from related coccidia. Int J Parasitol 2002; 32:929-46. [PMID: 12076623 DOI: 10.1016/s0020-7519(02)00094-2] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Neospora caninum is a protozoan parasite of animals, which before 1984 was misidentified as Toxoplasma gondii. Infection by this parasite is a major cause of abortion in cattle and causes paralysis in dogs. Since the original description of N. caninum in 1988, considerable progress has been made in the understanding of its life cycle, biology, genetics and diagnosis. In this article, the authors redescribe the parasite, distinguish it from related coccidia, and provide accession numbers to its type specimens deposited in museums.
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Affiliation(s)
- J P Dubey
- Parasite Biology Laboratory, Beltsville Agricultural Research Center, Animal and Natural Resources Institute, United States Department of Agriculture, Building 1001, BARC-East, Beltsville, MD 20705-2350, USA.
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Abstract
Neospora caninum is an apicomplexan parasite that causes neonatal neuromuscular disease in dogs and abortions in cattle. Bovine neosporosis is a major production problem worldwide. The parasite is transmitted to cattle via oocysts excreted by dogs or by transplacental transmission. Dogs are the only proven definitive host for N. caninum. One of 3 dogs fed mouse brains containing tissue cysts of a wild-type N. caninum strain CK0160SC3B (CKO) excreted oocysts in its feces. Two of 3 dogs fed mouse brains containing tissue cysts from a cloned line of the CKO strain excreted N. caninum oocysts in their feces. The results indicate that a single N. caninum tachyzoite contains all the genetic information needed to produce the asexual and sexual cycles in the canine intestine.
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Affiliation(s)
- D S Lindsay
- Center for Molecular Medicine and Infectious Diseases, Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg 24061-0342, USA
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