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Rose E, Moraes A, Shiroma T, Nitz N, Rosa ADC, Pratesi R, Hagström L, de Carvalho JL, Hecht M. Host DNA repair response to oxidative damage is modulated by Trypanosoma cruzi in a strain-dependent manner. Acta Trop 2021; 224:106127. [PMID: 34509459 DOI: 10.1016/j.actatropica.2021.106127] [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: 04/19/2021] [Revised: 08/26/2021] [Accepted: 09/02/2021] [Indexed: 11/16/2022]
Abstract
The conservation of genomic integrity and stability is essential for cell survival. DNA Damage Responses (DDRs) are considered of paramount importance for all living beings and involve mechanisms of cell cycle regulation and damage-specific DNA repair pathways. Hydrogen peroxide (H2O2) is a compound that, in supraphysiological concentrations, damages biomolecules including the DNA, causing base modifications and strand breaks. There is evidence that Trypanosoma cruzi, the protozoan that causes Chagas disease, interferes in the host cell's DNA metabolism. In order to investigate the influence of T. cruzi infection over the host cell capacity to withstand and repair DNA damage, we analyzed L6 cells infected with Berenice, and Colombiana T. cruzi strains according to their viability, proliferation, morphology, DNA degradation, expression of DNA repair, and cell cycle genes following H2O2 treatment. It was noted that T. cruzi infection might act as either a stressor or a protective element of host DNA, depending on the strain and H2O2 concentration. Cells infected with Berenice strain and treated with 0.8 mM H2O2 presented a reduced DNA damage response intensity (e.g., BER and HR). Infection with T. cruzi Colombiana prevented the activation of DNA repair pathways in response to 0.8mM and 1.6mM H2O2 (NER and MMR). Nevertheless, since cellular viability was not significantly compromised in Colombiana-infected cells following the oxidative insult, it is possible that the parasite directly influenced the host DNA repair machinery. Our results support the notion that T. cruzi is able to modulate the host cell DNA metabolism in a strain-dependent manner, an event which can be explored in future drug development strategies.
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Affiliation(s)
- Ester Rose
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasilia, Brazil.
| | - Aline Moraes
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasilia, Brazil
| | - Tatiana Shiroma
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasilia, Brazil
| | - Nadjar Nitz
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasilia, Brazil
| | - Ana de Cássia Rosa
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasilia, Brazil
| | - Riccardo Pratesi
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasilia, Brazil
| | - Luciana Hagström
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasilia, Brazil
| | - Juliana Lott de Carvalho
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasilia, Brazil
| | - Mariana Hecht
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasilia, Brasilia, Brazil
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Trasviña-Arenas CH, David SS, Delaye L, Azuara-Liceaga E, Brieba LG. Evolution of Base Excision Repair in Entamoeba histolytica is shaped by gene loss, gene duplication, and lateral gene transfer. DNA Repair (Amst) 2019; 76:76-88. [DOI: 10.1016/j.dnarep.2019.02.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 01/14/2019] [Accepted: 02/19/2019] [Indexed: 12/22/2022]
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3
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Azuara-Liceaga E, Betanzos A, Cardona-Felix CS, Castañeda-Ortiz EJ, Cárdenas H, Cárdenas-Guerra RE, Pastor-Palacios G, García-Rivera G, Hernández-Álvarez D, Trasviña-Arenas CH, Diaz-Quezada C, Orozco E, Brieba LG. The Sole DNA Ligase in Entamoeba histolytica Is a High-Fidelity DNA Ligase Involved in DNA Damage Repair. Front Cell Infect Microbiol 2018; 8:214. [PMID: 30050869 PMCID: PMC6052137 DOI: 10.3389/fcimb.2018.00214] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 06/07/2018] [Indexed: 01/03/2023] Open
Abstract
The protozoan parasite Entamoeba histolytica is exposed to reactive oxygen and nitric oxide species that have the potential to damage its genome. E. histolytica harbors enzymes involved in DNA repair pathways like Base and Nucleotide Excision Repair. The majority of DNA repairs pathways converge in their final step in which a DNA ligase seals the DNA nicks. In contrast to other eukaryotes, the genome of E. histolytica encodes only one DNA ligase (EhDNAligI), suggesting that this ligase is involved in both DNA replication and DNA repair. Therefore, the aim of this work was to characterize EhDNAligI, its ligation fidelity and its ability to ligate opposite DNA mismatches and oxidative DNA lesions, and to study its expression changes and localization during and after recovery from UV and H2O2 treatment. We found that EhDNAligI is a high-fidelity DNA ligase on canonical substrates and is able to discriminate erroneous base-pairing opposite DNA lesions. EhDNAligI expression decreases after DNA damage induced by UV and H2O2 treatments, but it was upregulated during recovery time. Upon oxidative DNA damage, EhDNAligI relocates into the nucleus where it co-localizes with EhPCNA and the 8-oxoG adduct. The appearance and disappearance of 8-oxoG during and after both treatments suggest that DNA damaged was efficiently repaired because the mainly NER and BER components are expressed in this parasite and some of them were modulated after DNA insults. All these data disclose the relevance of EhDNAligI as a specialized and unique ligase in E. histolytica that may be involved in DNA repair of the 8-oxoG lesions.
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Affiliation(s)
- Elisa Azuara-Liceaga
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City, Mexico,*Correspondence: Elisa Azuara-Liceaga
| | - Abigail Betanzos
- Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico,Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Cesar S. Cardona-Felix
- Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico,Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados, Irapuato, Mexico
| | | | - Helios Cárdenas
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City, Mexico
| | - Rosa E. Cárdenas-Guerra
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City, Mexico
| | - Guillermo Pastor-Palacios
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados, Irapuato, Mexico
| | - Guillermina García-Rivera
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - David Hernández-Álvarez
- Posgrado en Ciencias Genómicas, Universidad Autónoma de la Ciudad de México, Mexico City, Mexico
| | - Carlos H. Trasviña-Arenas
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados, Irapuato, Mexico
| | - Corina Diaz-Quezada
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados, Irapuato, Mexico
| | - Esther Orozco
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Mexico City, Mexico
| | - Luis G. Brieba
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados, Irapuato, Mexico,Luis G. Brieba
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Islam MT, Streck L, de Alencar MVOB, Cardoso Silva SW, da Conceição Machado K, da Conceição Machado K, Gomes Júnior AL, Paz MFCJ, da Mata AMOF, de Castro E Sousa JM, da Costa Junior JS, Lins Rolim HM, da Silva-Junior AA, de Carvalho Melo-Cavalcante AA. Evaluation of toxic, cytotoxic and genotoxic effects of phytol and its nanoemulsion. CHEMOSPHERE 2017; 177:93-101. [PMID: 28284120 DOI: 10.1016/j.chemosphere.2017.02.145] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 02/24/2017] [Accepted: 02/27/2017] [Indexed: 06/06/2023]
Abstract
Phytol (PYT) is a diterpenoid having important biological activity. However, it is a water non-soluble compound. This study aims to prepare PYT nanoemulsion (PNE) and evaluation of toxic, cytotoxic and genotoxic activities of PYT and PNE. For this, the PNE was prepared by the phase inversion method. The cytotoxicity test was performed in Artemia salina, while toxicity, cytotoxicity and genotoxicity in Allium cepa at concentrations of 2, 4, 8 and 16 mM. Potassium dichromate and copper sulfate were used as positive controls for the tests of A. salina and A. cepa, respectively. In addition, an adaptation response was detected in A. cepa by using the comet assay. The results suggest that both PYT and PNE exhibited toxic and cytotoxic effects at 4-16 mM in either test system, while genotoxicity at 2-16 mM in A. cepa. PNE exhibited more toxic, cytotoxic and genotoxic effects at 8 and 16 mM than the PYT. However, both PYT and PNE at 2 and 4 mM decreased the index and frequency of damage in A. cepa after 48 and 72 h, suggesting a possible adaptation response or DNA damage preventing capacity. Nanoemulsified PYT (PNE) may readily cross the biological membranes with an increase in bioavailability and produce more toxic, cytotoxic and genotoxic effects in the used test systems.
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Affiliation(s)
- Muhammad Torequl Islam
- Northeast Biotechnology Network (RENORBIO), Postgraduate Program in Pharmaceutical Sciences, Federal University of Piauí, Teresina, PI, 64.049-550, Brazil; Department of Pharmacy, Southern University Bangladesh, Mehedibag, Chittagong, 4000, Bangladesh.
| | - Leticia Streck
- Department of Pharmacy, Federal University of Rio Grande do Norte, 59012-570, Natal, RN, Brazil
| | | | - Samara Wanessa Cardoso Silva
- Northeast Biotechnology Network (RENORBIO), Postgraduate Program in Pharmaceutical Sciences, Federal University of Piauí, Teresina, PI, 64.049-550, Brazil
| | - Kátia da Conceição Machado
- Northeast Biotechnology Network (RENORBIO), Postgraduate Program in Pharmaceutical Sciences, Federal University of Piauí, Teresina, PI, 64.049-550, Brazil
| | - Keylla da Conceição Machado
- Northeast Biotechnology Network (RENORBIO), Postgraduate Program in Pharmaceutical Sciences, Federal University of Piauí, Teresina, PI, 64.049-550, Brazil
| | - Antonio Luiz Gomes Júnior
- Northeast Biotechnology Network (RENORBIO), Postgraduate Program in Pharmaceutical Sciences, Federal University of Piauí, Teresina, PI, 64.049-550, Brazil
| | - Márcia Fernanda Correia Jardim Paz
- Northeast Biotechnology Network (RENORBIO), Postgraduate Program in Pharmaceutical Sciences, Federal University of Piauí, Teresina, PI, 64.049-550, Brazil
| | - Ana Maria Oliveira Ferreira da Mata
- Northeast Biotechnology Network (RENORBIO), Postgraduate Program in Pharmaceutical Sciences, Federal University of Piauí, Teresina, PI, 64.049-550, Brazil
| | | | | | - Hercília Maria Lins Rolim
- Northeast Biotechnology Network (RENORBIO), Postgraduate Program in Pharmaceutical Sciences, Federal University of Piauí, Teresina, PI, 64.049-550, Brazil
| | | | - Ana Amélia de Carvalho Melo-Cavalcante
- Northeast Biotechnology Network (RENORBIO), Postgraduate Program in Pharmaceutical Sciences, Federal University of Piauí, Teresina, PI, 64.049-550, Brazil
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Fenoy IM, Bogado SS, Contreras SM, Gottifredi V, Angel SO. The Knowns Unknowns: Exploring the Homologous Recombination Repair Pathway in Toxoplasma gondii. Front Microbiol 2016; 7:627. [PMID: 27199954 PMCID: PMC4853372 DOI: 10.3389/fmicb.2016.00627] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 04/18/2016] [Indexed: 12/17/2022] Open
Abstract
Toxoplasma gondii is an apicomplexan parasite of medical and veterinary importance which causes toxoplasmosis in humans. Great effort is currently being devoted toward the identification of novel drugs capable of targeting such illness. In this context, we believe that the thorough understanding of the life cycle of this model parasite will facilitate the identification of new druggable targets in T. gondii. It is important to exploit the available knowledge of pathways which could modulate the sensitivity of the parasite to DNA damaging agents. The homologous recombination repair (HRR) pathway may be of particular interest in this regard as its inactivation sensitizes other cellular models such as human cancer to targeted therapy. Herein we discuss the information available on T. gondii's HRR pathway from the perspective of its conservation with respect to yeast and humans. Special attention was devoted to BRCT domain-containing and end-resection associated proteins in T. gondii as in other experimental models such proteins have crucial roles in early/late steps or HRR and in the pathway choice for double strand break resolution. We conclude that T. gondii HRR pathway is a source of several lines of investigation that allow to to comprehend the extent of diversification of HRR in T. gondii. Such an effort will serve to determine if HRR could represent a potential targer for the treatment of toxoplasmosis.
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Affiliation(s)
- Ignacio M Fenoy
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM Chascomús, Argentina
| | - Silvina S Bogado
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM Chascomús, Argentina
| | - Susana M Contreras
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM Chascomús, Argentina
| | - Vanesa Gottifredi
- Cell Cycle Genomic Instability Laboratory, Fundación Instituto Leloir, IIBBA-CONICET Chascomús, Argentina
| | - Sergio O Angel
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM Chascomús, Argentina
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Recombination and Diversification of the Variant Antigen Encoding Genes in the Malaria Parasite Plasmodium falciparum. Microbiol Spectr 2016; 2. [PMID: 26104446 DOI: 10.1128/microbiolspec.mdna3-0022-2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The most severe form of human malaria is caused by the protozoan parasite Plasmodium falciparum. These parasites invade and replicate within the circulating red blood cells of infected individuals leading to numerous disease manifestations, including severe anemia, altered circulation, and tissue inflammation. Malaria parasites are also known for their ability to maintain a chronic infection through antigenic variation, the ability to systematically alter the antigens displayed on the surface of infected cells and thereby avoid clearance by the host's antibody response. The genome of P. falciparum includes several large, multicopy gene families that encode highly variable forms of the surface proteins that are the targets of host immunity. Alterations in expression of genes within these families are responsible for antigenic variation. This process requires the continuous generation of new antigenic variants within these gene families, and studies have shown that new variants arise through extensive recombination and gene conversion events between family members. Malaria parasites possess an unusual complement of DNA repair pathways, thus the study of recombination between variant antigen encoding genes provides a unique view into the evolution of mobile DNA in an organism distantly related to the more closely studied model eukaryotes.
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El-Sayed NM, Aly EM. Toxoplasma gondii infection can induce retinal DNA damage: an experimental study. Int J Ophthalmol 2014; 7:431-6. [PMID: 24967186 DOI: 10.3980/j.issn.2222-3959.2014.03.08] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 12/30/2013] [Indexed: 11/02/2022] Open
Abstract
AIM To detect whether Toxoplasma gondii (T. gondii) infection of mice can induce retinal DNA damage. METHODS A total of 20 laboratory-bred male Swiss albino mice were used and divided into four groups: control group (non-infected animals); T. gondii infected group; immunosuppressed infected group; and infected group treated with sulfadiazine and pyrimethamine. Mice eyes were collected 6wk post infection and retinas were obtained. Each retina was immediately processed for comet assay and the frequency of tailed nuclei (DNA damage) was calculated. In addition, retinal DNA damage was revealed by various comet assay parameters that were provided by the image analysis software including tail length, percentage of DNA in the tail, percentage of tailed cells and tail moment. RESULTS The obtained results showed that T. gondii infection induced a statistically significant increase in the frequency of tailed nuclei, tail length, percentage of DNA in the tail, and tail moment in mice retinal cells compared to the control group (which showed some degree of DNA damage). In immunosuppressed infected group, retinal DNA damage was severing and there was significant increase in various comet assay parameters compared to both control and infected groups. After treatment with sulfadiazine and pyrimethamine, retinal DNA damage decreased and all comet assay parameters showed a statistical significant decrease compared to infected groups. CONCLUSION T. gondii infection can induce DNA damage in mice retinal cells.
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Affiliation(s)
- Nagwa Mostafa El-Sayed
- Department of Medical Parasitology, Research Institute of Ophthalmology, Giza 12556, Egypt
| | - Eman Mohamed Aly
- Department of Basic Science, Biophysics and Laser Science Unit, Research Institute of Ophthalmology, Giza 12556, Egypt
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Smolarz B, Wilczyński J, Nowakowska D. DNA repair mechanisms and Toxoplasma gondii infection. Arch Microbiol 2014; 196:1-8. [PMID: 24337694 PMCID: PMC3890036 DOI: 10.1007/s00203-013-0944-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 10/15/2013] [Accepted: 11/23/2013] [Indexed: 01/22/2023]
Abstract
Lately, we can observe significant progress in understanding mechanism of DNA repair owing to fast methods of DNA sequence analysis from different organisms the revealing of structure and function of DNA repair proteins in prokaryota and eukaryota. The protozoan parasites survival depends on DNA repair systems. Better understanding of DNA repair systems can help in new antipathogen drug development. This review is aimed at updating our current knowledge of the various repair pathways by providing an overview of DNA repair genes regarding Toxoplasma gondii infections and the corresponding proteins, participating either directly in DNA repair, or in checkpoint control and signaling of DNA damage.
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Affiliation(s)
- Beata Smolarz
- Department of Fetal-Maternal Medicine and Gynecology, Polish Mother’s Memorial Hospital Research Institute, 281/289 Rzgowska Street, 93-338 Lodz, Poland
| | - Jan Wilczyński
- Department of Fetal-Maternal Medicine and Gynecology, Polish Mother’s Memorial Hospital Research Institute, 281/289 Rzgowska Street, 93-338 Lodz, Poland
| | - Dorota Nowakowska
- Department of Fetal-Maternal Medicine and Gynecology, Polish Mother’s Memorial Hospital Research Institute, 281/289 Rzgowska Street, 93-338 Lodz, Poland
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El-Tokhy MA, Hussein NA, Bedewy AML, Barakat MR. XPD gene polymorphisms and the effects of induction chemotherapy in cytogenetically normal de novo acute myeloid leukemia patients. Hematology 2013; 19:397-403. [DOI: 10.1179/1607845413y.0000000144] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Mervat A. El-Tokhy
- Applied Medical Chemistry DepartmentMedical Research Institute, Alexandria University, Alexandria, Egypt
| | - Neveen A. Hussein
- Applied Medical Chemistry DepartmentMedical Research Institute, Alexandria University, Alexandria, Egypt
| | - Ahmed M. L. Bedewy
- Hematology DepartmentMedical Research Institute, Alexandria University, Alexandria, Egypt
| | - Mohammad R. Barakat
- Applied Medical Chemistry DepartmentMedical Research Institute, Alexandria University, Alexandria, Egypt
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10
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Kirkman LA, Lawrence EA, Deitsch KW. Malaria parasites utilize both homologous recombination and alternative end joining pathways to maintain genome integrity. Nucleic Acids Res 2013; 42:370-9. [PMID: 24089143 PMCID: PMC3874194 DOI: 10.1093/nar/gkt881] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Malaria parasites replicate asexually within their mammalian hosts as haploid cells and are subject to DNA damage from the immune response and chemotherapeutic agents that can significantly disrupt genomic integrity. Examination of the annotated genome of the parasite Plasmodium falciparum identified genes encoding core proteins required for the homologous recombination (HR) pathway for repairing DNA double-strand breaks (DSBs), but surprisingly none of the components of the canonical non-homologous end joining (C-NHEJ) pathway were identified. To better understand how malaria parasites repair DSBs and maintain genome integrity, we modified the yeast I-SceI endonuclease system to generate inducible, site-specific DSBs within the parasite’s genome. Analysis of repaired genomic DNA showed that parasites possess both a typical HR pathway resulting in gene conversion events as well as an end joining (EJ) pathway for repair of DSBs when no homologous sequence is available. The products of EJ were limited in number and identical products were observed in multiple independent experiments. The repair junctions frequently contained short insertions also found in the surrounding sequences, suggesting the possibility of a templated repair process. We propose that an alternative end-joining pathway rather than C-NHEJ, serves as a primary method for repairing DSBs in malaria parasites.
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Affiliation(s)
- Laura A Kirkman
- Department of Internal Medicine, Division of Infectious Diseases and Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10065, USA
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11
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Singh N, Bhattacharya A, Bhattacharya S. Homologous Recombination Occurs in Entamoeba and Is Enhanced during Growth Stress and Stage Conversion. PLoS One 2013; 8:e74465. [PMID: 24098652 PMCID: PMC3787063 DOI: 10.1371/journal.pone.0074465] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 08/01/2013] [Indexed: 12/28/2022] Open
Abstract
Homologous recombination (HR) has not been demonstrated in the parasitic protists Entamoeba histolytica or Entamoeba invadens, as no convenient method is available to measure it. However, HR must exist to ensure genome integrity, and possible genetic exchange, especially during stage conversion from trophozoite to cyst. Here we show the up regulation of mitotic and meiotic HR genes in Entamoeba during serum starvation, and encystation. To directly demonstrate HR we use a simple PCR-based method involving inverted repeats, which gives a reliable read out, as the recombination junctions can be determined by sequencing the amplicons. Using this read out, we demonstrate enhanced HR under growth stress in E. histolytica, and during encystation in E. invadens. We also demonstrate recombination between chromosomal inverted repeats. This is the first experimental demonstration of HR in Entamoeba and will help future investigations into this process, and to explore the possibility of meiosis in Entamoeba.
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Affiliation(s)
- Nishant Singh
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Alok Bhattacharya
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Sudha Bhattacharya
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
- * E-mail:
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Dubensky TW, Skoble J, Lauer P, Brockstedt DG. Killed but metabolically active vaccines. Curr Opin Biotechnol 2012; 23:917-23. [PMID: 22608846 DOI: 10.1016/j.copbio.2012.04.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 04/24/2012] [Indexed: 12/16/2022]
Abstract
Beginning in the 20th century and continuing into the new millennia, vaccines against numerous diseases have had an unquestioned principal role of both enhancing the quality of life and increasing life expectancy (Rappuoli R, Mandl CW, Black S, De Gregorio E: Vaccines for the twenty-first century society. Nat Rev Immunol 2011, 11:865-872). Despite this success and the development of sophisticated new vaccine technologies, there remain multiple infectious diseases including tuberculosis, malaria and AIDS that await an effective prophylactic vaccine. In addition, there have been recent clinical successes among individuals with cancer using vaccine treatment strategies-so-called therapeutic vaccines-that stimulate tumor specific immunity and increase survival (Kantoff PW, Higano CS, Shore ND, Berger ER, Small EJ, Penson DF, Redfern CH, Ferrari AC, Dreicer R, Sims RB, et al.: Sipuleucel-T immunotherapy for castration-resistant prostate cancer. New Engl J Med 2010, 363:411-422). Here we summarize a new class of vaccines termed Killed But Metabolically Active (KBMA). KBMA vaccines are whole pathogenic or attenuated organisms killed through photochemical inactivation and cannot cause disease, yet retain sufficient metabolic activity to initiate a potent immune response. KBMA vaccines have two broad applications. First, recombinant KBMA vaccines encoding selected antigens relevant to infectious disease or cancer can be used to elicit a desired immune response. In the second application, KBMA vaccines can be derived from attenuated forms of a targeted pathogen, allowing for the presentation of the entire antigenic repertoire to the immune system, of particular importance when the correlates of protection are unknown.
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Dobson R, Stockdale C, Lapsley C, Wilkes J, McCulloch R. Interactions among Trypanosoma brucei RAD51 paralogues in DNA repair and antigenic variation. Mol Microbiol 2011; 81:434-56. [PMID: 21615552 PMCID: PMC3170485 DOI: 10.1111/j.1365-2958.2011.07703.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Homologous recombination in Trypanosoma brucei is used for moving variant surface glycoprotein (VSG) genes into expression sites during immune evasion by antigenic variation. A major route for such VSG switching is gene conversion reactions in which RAD51, a universally conserved recombinase, catalyses homology-directed strand exchange. In any eukaryote, RAD51-directed strand exchange in vivo is mediated by further factors, including RAD51-related proteins termed Rad51 paralogues. These appear to be ubiquitously conserved, although their detailed roles in recombination remain unclear. In T. brucei, four putative RAD51 paralogue genes have been identified by sequence homology. Here we show that all four RAD51 paralogues act in DNA repair, recombination and RAD51 subnuclear dynamics, though not equivalently, while mutation of only one RAD51 paralogue gene significantly impedes VSG switching. We also show that the T. brucei RAD51 paralogues interact, and that the complexes they form may explain the distinct phenotypes of the mutants as well as observed expression interdependency. Finally, we document the Rad51 paralogues that are encoded by a wide range of protists, demonstrating that the Rad51 paralogue repertoire in T. brucei is unusually large among microbial eukaryotes and that one member of the protein family corresponds with a key, conserved eukaryotic Rad51 paralogue.
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Affiliation(s)
- Rachel Dobson
- College of Medical Veterinary and Life Sciences, University of Glasgow, Institute of Infection, Immunity and Inflammation, The Wellcome Trust Centre for Molecular Parasitology, Sir Graeme Davis Building, 120 University Place, Glasgow G128TA, UK
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Iyidogan P, Anderson KS. Lethal Mutagenesis as an Unconventional Approach to Combat HIV. ANTIVIRAL DRUG STRATEGIES 2011. [DOI: 10.1002/9783527635955.ch11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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15
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Pediatric leukemia predisposition syndromes: clues to understanding leukemogenesis. Cancer Genet 2011; 204:227-44. [DOI: 10.1016/j.cancergen.2011.04.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Accepted: 04/26/2011] [Indexed: 11/19/2022]
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16
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ERCC2 Lys751Gln and Asp312Asn polymorphisms and gastric cancer risk: a meta-analysis. J Cancer Res Clin Oncol 2010; 137:939-46. [DOI: 10.1007/s00432-010-0956-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Accepted: 10/12/2010] [Indexed: 01/30/2023]
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