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Dündar Orhan Y, Üstüntanır Dede AF, Duran Ş, Arslanyolu M. Use of E-64 cysteine protease inhibitor for the recombinant protein production in Tetrahymena thermophila. Eur J Protistol 2024; 94:126085. [PMID: 38703600 DOI: 10.1016/j.ejop.2024.126085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 04/24/2024] [Accepted: 04/24/2024] [Indexed: 05/06/2024]
Abstract
Tetrahymena thermophila is an alternative organism for recombinant protein production. However, the production efficiency in T. thermophila is quite low mainly due to the rich cysteine proteases. In this study, we studied whether supplementation of the E-64 inhibitor to T. thermophila cultures increases the recombinant protein production efficiency without any toxic side effects. Our study showed that supplementation of E-64 had no lethal effects on T. thermophila cells in flask culture at 30 °C and 38 °C. In vitro protease activity analysis using secretome as protease enzyme source from E-64-supplemented cell cultures showed a reduced protein substrate degradation using bovine serum albumin, rituximab, and milk lactoglobulin proteins. E-64 also prevented proteolysis of the recombinantly produced and secreted TtmCherry2-sfGFP fusion protein at some level. This reduced inhibitory effect of E-64 could be due to genetic compensation of the inhibited proteases. As a result, the 5 µM concentration of E-64 was found to be a non-toxic protease inhibitory supplement to improve extracellular recombinant protein production efficiency in T. thermophila. This study suggests that the use of E-64 may increase the efficiency of extracellular recombinant protein production by continuously reducing extracellular cysteine protease activity during cultivation.
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Affiliation(s)
- Yeliz Dündar Orhan
- Department of Advanced Technologies, Institute of Graduate Programs, Eskisehir Technical University, Yunus Emre Campus, Eskişehir 26470, Turkey.
| | - Ayça Fulya Üstüntanır Dede
- Department of Biology, Institute of Graduate Programs, Eskisehir Technical University, Yunus Emre Campus, Eskişehir 26470, Turkey.
| | - Şeyma Duran
- Department of Molecular Biology, Institute of Graduate Programs, Eskisehir Technical University, Yunus Emre Campus, Eskişehir 26470, Turkey.
| | - Muhittin Arslanyolu
- Department of Biology, Faculty of Sciences, Eskisehir Technical University, Yunusemre Campus, Eskişehir 26470, Turkey.
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2
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Duran Ş, Üstüntanir Dede AF, Dündar Orhan Y, Arslanyolu M. Genome-wide identification and in-silico analysis of papain-family cysteine protease encoding genes in Tetrahymena thermophila. Eur J Protistol 2024; 92:126033. [PMID: 38088016 DOI: 10.1016/j.ejop.2023.126033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/06/2023] [Accepted: 11/02/2023] [Indexed: 02/06/2024]
Abstract
Tetrahymena thermophila is a promising host for recombinant protein production, but its utilization in biotechnology is mostly limited due to the presence of intracellular and extracellular papain-family cysteine proteases (PFCPs). In this study, we employed bioinformatics approaches to investigate the T. thermophila PFCP genes and their encoded proteases (TtPFCPs), the most prominent protease family in the genome. Results from the multiple sequence alignment, protein modeling, and conserved motif analyses revealed that all TtPFCPs showed considerably high homology with mammalian cysteine cathepsins and contained conserved amino acid motifs. The total of 121 TtPFCP-encoding genes, 14 of which were classified as non-peptidase homologs, were found. Remaining 107 true TtPFCPs were divided into four distinct subgroups depending on their homology with mammalian lysosomal cathepsins: cathepsin L-like (TtCATLs), cathepsin B-like (TtCATBs), cathepsin C-like (TtCATCs), and cathepsin X-like (TtCATXs) PFCPs. The majority of true TtPFCPs (96 out of the total) were in TtCATL-like peptidase subgroup. Both phylogenetic and chromosomal localization analyses of TtPFCPs supported the hypothesis that TtPFCPs likely evolved through tandem gene duplication events and predominantly accumulated on micronuclear chromosome 5. Additionally, more than half of the identified TtPFCP genes are expressed in considerably low quantities compared to the rest of the TtPFCP genes, which are expressed at a higher level. However, their expression patterns fluctuate based on the stage of the life cycle. In conclusion, this study provides the first comprehensive in-silico analysis of TtPFCP genes and encoded proteases. The results would help designing an effective strategy for protease knockout mutant cell lines to discover biological function and to improve the recombinant protein production in T. thermophila.
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Affiliation(s)
- Şeyma Duran
- Department of Molecular Biology, Graduate School of Sciences, Eskisehir Technical University, Yunus Emre Campus, Eskişehir 26470, Türkiye.
| | - Ayça Fulya Üstüntanir Dede
- Department of Molecular Biology, Graduate School of Sciences, Eskisehir Technical University, Yunus Emre Campus, Eskişehir 26470, Türkiye.
| | - Yeliz Dündar Orhan
- Department of Advanced Technologies, Graduate School of Sciences, Eskisehir Technical University, Yunus Emre Campus, Eskişehir 26470, Türkiye.
| | - Muhittin Arslanyolu
- Department of Biology, Faculty of Sciences, Eskisehir Technical University, Yunusemre Campus, Eskişehir 26470, Türkiye.
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3
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Üstüntanır Dede AF, Arslanyolu M. Recombinant production of hormonally active human insulin from pre-proinsulin by Tetrahymena thermophila. Enzyme Microb Technol 2023; 170:110303. [PMID: 37562115 DOI: 10.1016/j.enzmictec.2023.110303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/12/2023]
Abstract
Alternative cell factories, such as the unicellular ciliate eukaryotic Tetrahymena thermophila, may be required for the production of protein therapeutics that are challenging to produce in conventional expression systems. T. thermophila (Tt) can secrete proteins with the post-translational modifications necessary for their function in humans. In this study, we tested if T. thermophila could process the human pre-proinsulin to produce hormonally active human insulin (hINS) with correct modifications. Flask and bioreactor culture of T. thermophila were used to produce the recombinant Tt-hINS either with or without an affinity tag from a codon-adapted pre-proinsulin sequence. Our results indicate that T. thermophila can produce a 6 kDa Tt-hINS monomer with the appropriate disulfide bonds after removal of the human insulin signal sequence or endogenous phospholipase A signal sequence, and the C-peptide of the human insulin. Additionally, Tt-hINS can form 12 kDa dimeric, 24 kDa tetrameric, and 36 kDa hexameric complexes. Tt-hINS-sfGFP fusion protein was localized to the vesicles within the cytoplasm and was secreted extracellularly. Assessing the affinity-purified Tt-hINS activity using the in vivo T. thermophila extracellular glucose drop assay, we observed that Tt-hINS induced a significant reduction (approximately 21 %) in extracellular glucose levels, indicative of its functional insulin activity. Our results demonstrate that T. thermophila is a promising candidate for the pharmaceutical and biotechnology industries as a host organism for the production of human protein drugs.
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Affiliation(s)
- Ayça Fulya Üstüntanır Dede
- Department of Biology, Institute of Graduate Programs, Eskisehir Technical University, Yunus Emre Campus, Eskisehir 26470, Turkey,.
| | - Muhittin Arslanyolu
- Department of Biology, Faculty of Sciences, Eskisehir Technical University, Yunus Emre Campus, Eskisehir 26470, Turkey.
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4
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Çalıseki M, Üstüntanır Dede AF, Arslanyolu M. Characterization and use of Tetrahymena thermophila artificial chromosome 2 (TtAC2) constructed by biomimetic of macronuclear rDNA minichromosome. Microbiol Res 2021; 248:126764. [PMID: 33887535 DOI: 10.1016/j.micres.2021.126764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/25/2021] [Accepted: 03/31/2021] [Indexed: 11/26/2022]
Abstract
Efficient expression vectors for unicellular ciliate eukaryotic Tetrahymena thermophila are still needed in recombinant biology and biotechnology applications. Previously, the construction of the T. thermophila Macronuclear Artificial Chromosome 1 (TtAC1) vector revealed additional needs for structural improvements such as better in vivo stability and maintenance as a recombinant protein expression platform. In this study, we designed an efficiently maintained artificial chromosome by biomimetic of the native macronuclear rDNA minichromosome. TtAC2 was constructed by sequential cloning of subtelomeric 3'NTS region (1.8 kb), an antibiotic resistance gene cassette (2 kb neo4), a gene expression cassette (2 kb TtsfGFP), rDNA coding regions plus a dominant C3 origin sequence (10.3 kb), and telomeres (2.4 kb) in a pUC19 backbone plasmid (2.6 kb). The 21 kb TtAC2 was characterized using fluorescence microscopy, qPCR, western blot and Southern blot after its transformation to vegetative T. thermophila CU428.2 strain, which has a recessive B origin allele. All experimental data show that circular or linear forms of novel TtAC2 were maintained as free replicons in T. thermophila macronucleus with or without antibiotic treatment. Notably, TtAC2 carrying strains expressed a TtsfGFP marker protein, demonstrating the efficacy and functionality of the protein expression platform. We show that TtAC2 is functionally maintained for more than two months, and can be efficiently used in recombinant DNA, and protein production applications.
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Affiliation(s)
- Mehmet Çalıseki
- Department of Advanced Technologies, Graduate School of Sciences, Eskisehir Technical University, Yunusemre Campus, Eskisehir, 26470, Turkey.
| | - Ayça Fulya Üstüntanır Dede
- Department of Biology, Institute of Graduate Programs, Eskisehir Technical University, Yunusemre Campus, Eskisehir, 26470, Turkey.
| | - Muhittin Arslanyolu
- Department of Biology, Faculty of Sciences, Eskisehir Technical University, Yunusemre Campus, Eskisehir, 26470, Turkey.
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5
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Elguero ME, Tomazic ML, Montes MG, Florin-Christensen M, Schnittger L, Nusblat AD. The Cryptosporidium parvum gp60 glycoprotein expressed in the ciliate Tetrahymena thermophila is immunoreactive with sera of calves infected with Cryptosporidium oocysts. Vet Parasitol 2019; 271:45-50. [PMID: 31303202 DOI: 10.1016/j.vetpar.2019.06.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 06/07/2019] [Accepted: 06/10/2019] [Indexed: 11/27/2022]
Abstract
Cryptosporidium parvum is a protozoan parasite of the phylum Apicomplexa responsible for cryptosporidiosis in calves, a disease that causes significant diarrhea and impairs gain of body weight, generating important production losses. As to now, no effective drugs or vaccines are available for the treatment or prevention of bovine cryptosporidiosis. Several reports suggest that development of a vaccine to prevent cryptosporidiosis is feasible, but relatively few vaccine candidates have been characterized and tested. The most prominent C. parvum antigen is gp60, an O-glycosylated mucin-like protein tethered to the parasite membrane by a glycosylphosphatidylinositol (GPI) anchor. Gp60 has been shown to be involved in essential mechanisms for the survival of C. parvum, such as recognition, adhesion to, and invasion of host cells. This work was aimed at expressing gp60 in Tetrahymena thermophila, a ciliated protozoon with numerous advantages for the heterologous expression of eukaryotic proteins, as a first approach for the development of a recombinant vaccine for bovine cryptosporidiosis. T. thermophila-expressed gp60 localized to the protozoon cell surface and oral apparatus, and partitioned into the Triton X-114 detergent phase. This indicates that the protein entered the reticuloendothelial system of the ciliate, and suggests it contains a GPI-anchor. Homogenates of gp60-expressing T. thermophila cells were recognized by sera from calves naturally infected with C. parvum demonstrating their immunoreactivity. In summary, the heterologous expression of gp60, a C. parvum-encoded GPI-anchored protein, has been successfully demonstrated in the ciliate T. thermophila.
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Affiliation(s)
- María E Elguero
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Nanobiotecnología (NANOBIOTEC), Facultad de Farmacia y Bioquímica, Junín, 956 (C1113AAD), Ciudad Autónoma de Buenos Aires, Argentina
| | - Mariela L Tomazic
- Instituto Nacional de Tecnología Agropecuaria. CONICET. Instituto de Patobiología Veterinaria (IPVET), CICVyA, Hurlingham, Prov. de Buenos Aires, Argentina; CONICET, Ciudad Autónoma de Buenos Aires, Argentina
| | - María G Montes
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Nanobiotecnología (NANOBIOTEC), Facultad de Farmacia y Bioquímica, Junín, 956 (C1113AAD), Ciudad Autónoma de Buenos Aires, Argentina
| | - Mónica Florin-Christensen
- Instituto Nacional de Tecnología Agropecuaria. CONICET. Instituto de Patobiología Veterinaria (IPVET), CICVyA, Hurlingham, Prov. de Buenos Aires, Argentina; CONICET, Ciudad Autónoma de Buenos Aires, Argentina
| | - Leonhard Schnittger
- Instituto Nacional de Tecnología Agropecuaria. CONICET. Instituto de Patobiología Veterinaria (IPVET), CICVyA, Hurlingham, Prov. de Buenos Aires, Argentina; CONICET, Ciudad Autónoma de Buenos Aires, Argentina
| | - Alejandro D Nusblat
- Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto de Nanobiotecnología (NANOBIOTEC), Facultad de Farmacia y Bioquímica, Junín, 956 (C1113AAD), Ciudad Autónoma de Buenos Aires, Argentina.
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Characterization and immune regulation role of an immobilization antigen from Cryptocaryon irritans on groupers. Sci Rep 2019; 9:1029. [PMID: 30705292 PMCID: PMC6355922 DOI: 10.1038/s41598-018-25710-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 04/25/2018] [Indexed: 11/08/2022] Open
Abstract
Immobilization antigens (i-antigens) are surface membrane proteins that are widely recognized to be the ideal candidates as vaccines antigens for immunization against Cryptocaryon irritans. In this study, we cloned a putative i-antigen gene from C. irritans, which was expressed in all three stages of the C. irritans life-cycle, and localized primarily to the cell surface. The recombinant GDCI3 i-antigen was expressed and purified using the free-living ciliate, Tetrahymena thermophila as an expression system. The purified recombinant protein was recognized by rabbit anti-C. irritans antiserum and was capable of eliciting immobilizing antibodies in rabbits and fish suggesting that the antigen itself was correctly folded. Following immunization and parasite challenge, groupers vaccinated with, recombinant GDCI3 i-antigen had a 25% cumulative percent survival rate compared to 8.3% for controls. Both non-specific and parasite-specific IgMs were generated in fish following immunization, with the levels of both increasing following challenge. Parasite-specific IgM in mucus could only be elicited after challenge of the GDCI3 i-antigen vaccinated groupers. To our knowledge, this is the first report using the Tetrahymena expression system to generate C. irritans i-antigens and investigate their use for fish vaccination.
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Affiliation(s)
- María E. Elguero
- Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Nanobiotecnología (NANOBIOTEC), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Clara B. Nudel
- Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Nanobiotecnología (NANOBIOTEC), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Alejandro D. Nusblat
- Facultad de Farmacia y Bioquímica, Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Nanobiotecnología (NANOBIOTEC), Universidad de Buenos Aires, Buenos Aires, Argentina
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Wall KP, Pagratis M, Armstrong G, Balsbaugh JL, Verbeke E, Pearson CG, Hough LE. Molecular Determinants of Tubulin's C-Terminal Tail Conformational Ensemble. ACS Chem Biol 2016; 11:2981-2990. [PMID: 27541566 DOI: 10.1021/acschembio.6b00507] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Tubulin is important for a wide variety of cellular processes including cell division, ciliogenesis, and intracellular trafficking. To perform these diverse functions, tubulin is regulated by post-translational modifications (PTM), primarily at the C-terminal tails of both the α- and β-tubulin heterodimer subunits. The tubulin C-terminal tails are disordered segments that are predicted to extend from the ordered tubulin body and may regulate both intrinsic properties of microtubules and the binding of microtubule associated proteins (MAP). It is not understood how either interactions with the ordered tubulin body or PTM affect tubulin's C-terminal tails. To probe these questions, we developed a method to isotopically label tubulin for C-terminal tail structural studies by NMR. The conformational changes of the tubulin tails as a result of both proximity to the ordered tubulin body and modification by mono- and polyglycine PTM were determined. The C-terminal tails of the tubulin dimer are fully disordered and, in contrast with prior simulation predictions, exhibit a propensity for β-sheet conformations. The C-terminal tails display significant chemical shift differences as compared to isolated peptides of the same sequence, indicating that the tubulin C-terminal tails interact with the ordered tubulin body. Although mono- and polyglycylation affect the chemical shift of adjacent residues, the conformation of the C-terminal tail appears insensitive to the length of polyglycine chains. Our studies provide important insights into how the essential disordered domains of tubulin function.
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Affiliation(s)
| | - Maria Pagratis
- University of Colorado, Boulder, Colorado, United States
| | | | | | - Eric Verbeke
- University of Colorado, Boulder, Colorado, United States
| | - Chad G. Pearson
- University of Colorado, Anschutz Medical Campus, Colorado, United States
| | - Loren E. Hough
- University of Colorado, Boulder, Colorado, United States
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Calow J, Behrens AJ, Mader S, Bockau U, Struwe WB, Harvey DJ, Cormann KU, Nowaczyk MM, Loser K, Schinor D, Hartmann MWW, Crispin M. Antibody production using a ciliate generates unusual antibody glycoforms displaying enhanced cell-killing activity. MAbs 2016; 8:1498-1511. [PMID: 27594301 PMCID: PMC5098438 DOI: 10.1080/19420862.2016.1228504] [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] [Indexed: 12/21/2022] Open
Abstract
Antibody glycosylation is a key parameter in the optimization of antibody therapeutics. Here, we describe the production of the anti-cancer monoclonal antibody rituximab in the unicellular ciliate, Tetrahymena thermophila. The resulting antibody demonstrated enhanced antibody-dependent cell-mediated cytotoxicity, which we attribute to unusual N-linked glycosylation. Detailed chromatographic and mass spectrometric analysis revealed afucosylated, oligomannose-type glycans, which, as a whole, displayed isomeric structures that deviate from the typical human counterparts, but whose branches were equivalent to fragments of metabolic intermediates observed in human glycoproteins. From the analysis of deposited crystal structures, we predict that the ciliate glycans adopt protein-carbohydrate interactions with the Fc domain that closely mimic those of native complex-type glycans. In addition, terminal glucose structures were identified that match biosynthetic precursors of human glycosylation. Our results suggest that ciliate-based expression systems offer a route to large-scale production of monoclonal antibodies exhibiting glycosylation that imparts enhanced cell killing activity.
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Affiliation(s)
| | - Anna-Janina Behrens
- b Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford , Oxford , UK
| | | | | | - Weston B Struwe
- b Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford , Oxford , UK
| | - David J Harvey
- b Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford , Oxford , UK
| | - Kai U Cormann
- c Plant Biochemistry, Ruhr University Bochum , Bochum , Germany
| | - Marc M Nowaczyk
- c Plant Biochemistry, Ruhr University Bochum , Bochum , Germany
| | - Karin Loser
- d Department of Dermatology , University of Münster , Münster , Germany
| | - Daniel Schinor
- e Wessling GmbH, Pharmaanalytik Münster , Münster , Germany
| | | | - Max Crispin
- b Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford , Oxford , UK
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Cowan GJM, Bockau U, Eleni-Muus J, Aldag I, Samuel K, Creasey AM, Hartmann MWW, Cavanagh DR. A novel malaria vaccine candidate antigen expressed in Tetrahymena thermophila. PLoS One 2014; 9:e87198. [PMID: 24489871 PMCID: PMC3906136 DOI: 10.1371/journal.pone.0087198] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 12/20/2013] [Indexed: 01/15/2023] Open
Abstract
Development of effective malaria vaccines is hampered by the problem of producing correctly folded Plasmodium proteins for use as vaccine components. We have investigated the use of a novel ciliate expression system, Tetrahymena thermophila, as a P. falciparum vaccine antigen platform. A synthetic vaccine antigen composed of N-terminal and C-terminal regions of merozoite surface protein-1 (MSP-1) was expressed in Tetrahymena thermophila. The recombinant antigen was secreted into the culture medium and purified by monoclonal antibody (mAb) affinity chromatography. The vaccine was immunogenic in MF1 mice, eliciting high antibody titers against both N- and C-terminal components. Sera from immunized animals reacted strongly with P. falciparum parasites from three antigenically different strains by immunofluorescence assays, confirming that the antibodies produced are able to recognize parasite antigens in their native form. Epitope mapping of serum reactivity with a peptide library derived from all three MSP-1 Block 2 serotypes confirmed that the MSP-1 Block 2 hybrid component of the vaccine had effectively targeted all three serotypes of this polymorphic region of MSP-1. This study has successfully demonstrated the use of Tetrahymena thermophila as a recombinant protein expression platform for the production of malaria vaccine antigens.
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Affiliation(s)
- Graeme J. M. Cowan
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | | | | | | | - Kay Samuel
- Cell Therapy Group, Scottish National Blood Transfusion Service, Edinburgh, United Kingdom
| | - Alison M. Creasey
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
| | | | - David R. Cavanagh
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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11
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Freire SLS, Tanner B. Additive-free digital microfluidics. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:9024-30. [PMID: 23758672 DOI: 10.1021/la401616j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Digital microfluidics, a technique for manipulation of droplets, is becoming increasingly important for the development of miniaturized platforms for laboratory processes. Despite the enthusiasm, droplet motion is frequently hindered by the desorption of proteins or other analytes to surfaces. Current approaches to minimize this unwanted surface fouling involve the addition of extra species to the droplet or its surroundings, which might be problematic depending on the droplet content. Here, a new strategy is introduced to move droplets containing cells and other analytes on solid substrates, without extra moieties; in particular, droplets with bovine serum albumin could be moved at a concentration 2000 times higher than previously reported (without additives). This capability is achieved by using a soot-based superamphiphobic surface combined with a new device geometry, which favors droplet rolling. Contrasting with electrowetting, wetting forces are not required for droplet motion.
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Affiliation(s)
- Sergio L S Freire
- Department of Mathematics, Physics and Statistics, University of the Sciences, Philadelphia, Pennsylvania 19104, United States.
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12
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Abstract
In this article, we will cover the folding of proteins in the lumen of the endoplasmic reticulum (ER), including the role of three types of covalent modifications: signal peptide removal, N-linked glycosylation, and disulfide bond formation, as well as the function and importance of resident ER folding factors. These folding factors consist of classical chaperones and their cochaperones, the carbohydrate-binding chaperones, and the folding catalysts of the PDI and proline cis-trans isomerase families. We will conclude with the perspective of the folding protein: a comparison of characteristics and folding and exit rates for proteins that travel through the ER as clients of the ER machinery.
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Affiliation(s)
- Ineke Braakman
- Cellular Protein Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
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13
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Cheaib M, Simon M. Dynamic chromatin remodelling of ciliate macronuclear DNA as determined by an optimized chromatin immunoprecipitation (ChIP) method for Paramecium tetraurelia. Appl Microbiol Biotechnol 2013; 97:2661-70. [PMID: 23385475 DOI: 10.1007/s00253-013-4708-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 01/04/2013] [Accepted: 01/07/2013] [Indexed: 01/08/2023]
Abstract
We report the detailed evaluation of crucial parameters for chromatin immunoprecipitation (ChIP) of macronuclear DNA in the unicellular eukaryote Paramecium tetraurelia. Optimized parameters include crosslinking conditions, chromatin sonication and antibody titration thus providing a detailed protocol for successful ChIP in P. tetraurelia. As this ciliate is bacterivorous and RNAi by feeding represents a powerful tool for analysis of gene function, we moreover determined the effects of ingested nucleic acids by food bacteria. Feasibility of our protocol is demonstrated by characterisation of chromatin remodelling at promoters of cytosolic HSP70 isoforms during transcriptional activation under heat shock conditions by analyzing RNA abundance, nucleosome occupancy and levels of H3 lysine 9 acetylation.
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Affiliation(s)
- Miriam Cheaib
- Faculty of Biology, Molecular Protistology, University of Kaiserslautern, Gottlieb-Daimler Straße Building 14, 67663 Kaiserslautern, Germany
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14
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Zimmermann H, Zebisch M, Sträter N. Cellular function and molecular structure of ecto-nucleotidases. Purinergic Signal 2012; 8:437-502. [PMID: 22555564 PMCID: PMC3360096 DOI: 10.1007/s11302-012-9309-4] [Citation(s) in RCA: 763] [Impact Index Per Article: 63.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 02/01/2012] [Indexed: 12/12/2022] Open
Abstract
Ecto-nucleotidases play a pivotal role in purinergic signal transmission. They hydrolyze extracellular nucleotides and thus can control their availability at purinergic P2 receptors. They generate extracellular nucleosides for cellular reuptake and salvage via nucleoside transporters of the plasma membrane. The extracellular adenosine formed acts as an agonist of purinergic P1 receptors. They also can produce and hydrolyze extracellular inorganic pyrophosphate that is of major relevance in the control of bone mineralization. This review discusses and compares four major groups of ecto-nucleotidases: the ecto-nucleoside triphosphate diphosphohydrolases, ecto-5'-nucleotidase, ecto-nucleotide pyrophosphatase/phosphodiesterases, and alkaline phosphatases. Only recently and based on crystal structures, detailed information regarding the spatial structures and catalytic mechanisms has become available for members of these four ecto-nucleotidase families. This permits detailed predictions of their catalytic mechanisms and a comparison between the individual enzyme groups. The review focuses on the principal biochemical, cell biological, catalytic, and structural properties of the enzymes and provides brief reference to tissue distribution, and physiological and pathophysiological functions.
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Affiliation(s)
- Herbert Zimmermann
- Institute of Cell Biology and Neuroscience, Molecular and Cellular Neurobiology, Biologicum, Goethe-University Frankfurt, Max-von-Laue-Str. 13, 60438, Frankfurt am Main, Germany.
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Conservation and innovation in Tetrahymena membrane traffic: proteins, lipids, and compartments. Methods Cell Biol 2012; 109:141-75. [PMID: 22444145 DOI: 10.1016/b978-0-12-385967-9.00006-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The past decade has seen a significant expansion in our understanding of membrane traffic in Tetrahymena thermophila, facilitated by the development of new experimental tools and by the availability of the macronuclear genome sequence. Here we review studies on multiple pathways of uptake and secretion, as well as work on metabolism of membrane lipids. We discuss evidence for conservation versus innovation in the mechanisms used in ciliates compared with those in other eukaryotic lineages, and raise the possibility that existing gene expression databases can be exploited to analyze specific pathways of membrane traffic in these cells.
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