Distinct Phenotypes Caused by Mutation of MSH2 in Trypanosome Insect and Mammalian Life Cycle Forms Are Associated with Parasite Adaptation to Oxidative Stress
Autor: | Ceres Luciana Alves, Viviane Grazielle-Silva, Richard McCulloch, Tehseen Fatima Zeb, Julia B. Miranda, Priscila C. Campos, Jason Bolderson, Santuza M. R. Teixeira, Carlos Renato Machado |
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Rok vydání: | 2015 |
Předmět: |
congenital
hereditary and neonatal diseases and abnormalities lcsh:Arctic medicine. Tropical medicine Guanine lcsh:RC955-962 DNA repair Trypanosoma cruzi Trypanosoma brucei brucei Trypanosoma brucei medicine.disease_cause 03 medical and health sciences medicine Animals 030304 developmental biology Genetics 0303 health sciences Parasitic life cycles Mutation biology lcsh:Public aspects of medicine 030302 biochemistry & molecular biology Public Health Environmental and Occupational Health Wild type lcsh:RA1-1270 DNA Protozoan biology.organism_classification digestive system diseases 3. Good health Oxidative Stress Protein Transport Infectious Diseases MutS Homolog 2 Protein Gene Expression Regulation Trypanosoma DNA mismatch repair RNA Interference Gene Deletion Microsatellite Repeats Research Article |
Zdroj: | PLoS Neglected Tropical Diseases PLoS Neglected Tropical Diseases, Vol 9, Iss 6, p e0003870 (2015) |
ISSN: | 1935-2735 |
Popis: | Background DNA repair mechanisms are crucial for maintenance of the genome in all organisms, including parasites where successful infection is dependent both on genomic stability and sequence variation. MSH2 is an early acting, central component of the Mismatch Repair (MMR) pathway, which is responsible for the recognition and correction of base mismatches that occur during DNA replication and recombination. In addition, recent evidence suggests that MSH2 might also play an important, but poorly understood, role in responding to oxidative damage in both African and American trypanosomes. Methodology/Principal Findings To investigate the involvement of MMR in the oxidative stress response, null mutants of MSH2 were generated in Trypanosoma brucei procyclic forms and in Trypanosoma cruzi epimastigote forms. Unexpectedly, the MSH2 null mutants showed increased resistance to H2O2 exposure when compared with wild type cells, a phenotype distinct from the previously observed increased sensitivity of T. brucei bloodstream forms MSH2 mutants. Complementation studies indicated that the increased oxidative resistance of procyclic T. brucei was due to adaptation to MSH2 loss. In both parasites, loss of MSH2 was shown to result in increased tolerance to alkylation by MNNG and increased accumulation of 8-oxo-guanine in the nuclear and mitochondrial genomes, indicating impaired MMR. In T. cruzi, loss of MSH2 also increases the parasite capacity to survive within host macrophages. Conclusions/Significance Taken together, these results indicate MSH2 displays conserved, dual roles in MMR and in the response to oxidative stress. Loss of the latter function results in life cycle dependent differences in phenotypic outcomes in T. brucei MSH2 mutants, most likely because of the greater burden of oxidative stress in the insect stage of the parasite. Author Summary Trypanosoma brucei and Trypanosoma cruzi are protozoa parasites that cause sleeping sickness and Chagas disease, respectively, two neglected tropical diseases endemic in sub-Saharan Africa and Latin America. The high genetic diversity found in the T. cruzi population and the highly diverse repertoire of surface glycoprotein genes found in T. brucei are crucial factors that ensure a successful infection in their hosts. Besides responding to host immune responses, these parasites must deal with various sources of oxidative stress that can cause DNA damage. Thus, by determining the right balance between genomic stability and genetic variation, DNA repair pathways have a big impact in the ability of these parasites to maintain infection. This study is focused on the role of a DNA mismatch repair (MMR) protein named MSH2 in protecting these parasites’ DNA against oxidative assault. Using knock-out mutants, we showed that, besides acting in the MMR pathway as a key protein that recognizes and repairs base mismatches, insertions or deletions that can occur after DNA replication, MSH2 has an additional role in the oxidative stress response. Importantly, this extra role of MSH2 seems to be independent of other MMR components and dependent on the parasite developmental stage. |
Databáze: | OpenAIRE |
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