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Gonçalves-Santos E, Caldas IS, Fernandes VÂ, Franco LL, Pelozo MF, Feltrim F, Maciel JS, Machado JVC, Gonçalves RV, Novaes RD. Pharmacological potential of new metronidazole/eugenol/dihydroeugenol hybrids against Trypanosoma cruzi in vitro and in vivo. Int Immunopharmacol 2023; 121:110416. [PMID: 37295025 DOI: 10.1016/j.intimp.2023.110416] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 05/17/2023] [Accepted: 05/30/2023] [Indexed: 06/11/2023]
Abstract
AIMS From well-delimited immunomodulatory, redox and antimicrobial properties; metronidazole and eugenol were used as structural platforms to assembly two new molecular hybrids (AD06 and AD07), whose therapeutic relevance was analyzed on T. cruzi infection in vitro and in vivo. METHODS Non-infected, T. cruzi-infected H9c2 cardiomyocytes, and mice non-treated and treated with vehicle, benznidazole (Bz - reference drug), AD06 and AD07 were investigated. Parasitological, prooxidant, antioxidant, microstructural, immunological, and hepatic function markers were analyzed. RESULTS Our findings indicated that in addition to having a direct antiparasitic effect on T. cruzi, metronidazole/eugenol hybrids (especially AD07) attenuated cellular parasitism, reactive species biosynthesis and oxidative stress in infected cardiomyocytes in vitro. Although AD06 and AD07 exerted no relevant impact on antioxidant enzymes activity (CAT, SOD, GR and GPx) in host cells, these drugs (especially AD07) attenuated trypanothione reductase activity in T. cruzi, which increased parasite's susceptibility to in vitro pro-oxidant challenge. AD06 and AD07 were well tolerated and do not determine humoral response suppression, mortality (100 % survival) or hepatotoxicity in mice, as indicated by transaminases plasma levels. AD07 also induced relevant in vivo antiparasitic and cardioprotective effects, attenuating parasitemia, cardiac parasite load and myocarditis in T. cruzi-infected mice. Although this cardioprotective response is potentially related to AD07 antiparasitic effect, a direct anti-inflammatory potential of this molecular hybrid cannot be ruled out. CONCLUSION Taken together, our findings indicated that the new molecular hybrid AD07 stood out as a potentially relevant candidate for the development of new, safe and more effective drug regimens for T. cruzi infection treatment.
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Affiliation(s)
- Elda Gonçalves-Santos
- Programa de Pós-Graduação em Biociências Aplicadas à Saúde, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil
| | - Ivo S Caldas
- Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil; Instituto de Ciências Biomédicas, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil
| | - Valquiria  Fernandes
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil
| | - Lucas L Franco
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil; Faculdade de Ciências Farmacêuticas, Departamento de Alimentos e Medicamentos, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil
| | - Mônica F Pelozo
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil; Faculdade de Ciências Farmacêuticas, Departamento de Alimentos e Medicamentos, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil
| | - Fernando Feltrim
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil; Faculdade de Ciências Farmacêuticas, Departamento de Alimentos e Medicamentos, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil
| | - Juliana S Maciel
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil; Faculdade de Ciências Farmacêuticas, Departamento de Alimentos e Medicamentos, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil
| | - Jose Vaz C Machado
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil
| | - Reggiani V Gonçalves
- Departamento de Biologia Animal, Programa de Pós-Graduação em Biologia Animal, Universidade Federal de Viçosa, Viçosa 36570-900, Minas Gerais, Brazil
| | - Rômulo D Novaes
- Programa de Pós-Graduação em Biociências Aplicadas à Saúde, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil; Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil; Instituto de Ciências Biomédicas, Universidade Federal de Alfenas, Alfenas 37130-001, Minas Gerais, Brazil; Departamento de Biologia Animal, Programa de Pós-Graduação em Biologia Animal, Universidade Federal de Viçosa, Viçosa 36570-900, Minas Gerais, Brazil.
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Poveda A, Méndez MÁ, Armijos-Jaramillo V. Analysis of DNA Polymerases Reveals Specific Genes Expansion in Leishmania and Trypanosoma spp. Front Cell Infect Microbiol 2020; 10:570493. [PMID: 33117729 PMCID: PMC7576959 DOI: 10.3389/fcimb.2020.570493] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/02/2020] [Indexed: 01/01/2023] Open
Abstract
Leishmaniasis and trypanosomiasis are largely neglected diseases prevailing in tropical and subtropical conditions. These are an arthropod-borne zoonosis that affects humans and some animals and is caused by infection with protozoan of the genera Leishmania and Trypanosoma, respectively. These parasites present high genomic plasticity and are able to adapt themselves to adverse conditions like the attack of host cells or toxicity induced by drug exposure. Different mechanisms allow these adapting responses induced by stress, such as mutation, chromosomal rearrangements, establishment of mosaic ploidies, and gene expansion. Here we describe how a subset of genes encoding for DNA polymerases implied in repairing/translesion (TLS) synthesis are duplicated in some pathogenic species of the Trypanosomatida order and a free-living species from the Bodonida order. These enzymes are both able to repair DNA, but are also error-prone under certain situations. We discuss about the possibility that these enzymes can act as a source of genomic variation promoting adaptation in trypanosomatids.
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Affiliation(s)
- Ana Poveda
- DNA Replication and Genome Instability Unit, Grupo de Investigación en Biodiversidad, Zoonosis y Salud Pública (GIBCIZ), Instituto de Investigación en Salud Pública y Zoonosis-CIZ, Facultad de Ciencias Químicas, Universidad Central del Ecuador, Quito, Ecuador.,Departamento de Bioquímica y Biología Molecular, Universidad de Valencia, Burjassot, Spain
| | - Miguel Ángel Méndez
- Grupo de Química Computacional y Teórica, Universidad San Francisco de Quito, Quito, Ecuador
| | - Vinicio Armijos-Jaramillo
- Grupo de Bio-Quimioinformática, Carrera de Ingeniería en Biotecnología, Facultad de Ingeniería y Ciencias Aplicadas, Universidad de Las Américas, Quito, Ecuador
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3
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Marco Antônio Salgado Martins T, de Figueiredo Peloso E, Costa-Silva HM, Rajão MA, Van Houten B, Machado CR, Ramos Gadelha F. Mitochondrial behavior during nuclear and mitochondrial DNA repair in Trypanosoma cruzi epimastigotes. Exp Parasitol 2020; 219:108016. [PMID: 33035543 DOI: 10.1016/j.exppara.2020.108016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/30/2020] [Accepted: 10/05/2020] [Indexed: 12/12/2022]
Abstract
Different genotoxic agents can lead to DNA single- and double-strand breaks, base modification and oxidation. As most living organisms, Trypanosoma cruzi is subjected to oxidative stress during its life cycle; thus, DNA repair is essential for parasite survival and establishment of infection. The mitochondrion plays important roles beyond the production of ATP. For example, it is a source of signaling molecules, such as the superoxide anion and H2O2. Since T. cruzi has only one mitochondrion, the integrity of this organelle is pivotal for parasite viability. H2O2 and methyl methanesulfonate cause DNA lesions in T. cruzi that are repaired by different DNA repair pathways. Herein, we evaluate mitochondrial involvement during the repair of nuclear and mitochondrial DNA in T. cruzi epimastigotes incubated with these two genotoxic agents under conditions that induce repairable DNA damage. Overall, in both treatments, an increase in oxygen consumption rates and in mitochondrial H2O2 release was observed, as well as maintenance of ATP levels compared to control. Interestingly, these changes coincided with DNA repair kinetics, suggesting the importance of the mitochondrion for this energy-consuming process.
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Affiliation(s)
| | | | | | - Matheus Andrade Rajão
- Departamento de Bioquímica e Imunologia, ICB - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Bennet Van Houten
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine and the University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, PA, United States
| | - Carlos Renato Machado
- Departamento de Bioquímica e Imunologia, ICB - UFMG, Belo Horizonte, Minas Gerais, Brazil
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4
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Leal AZ, Schwebs M, Briggs E, Weisert N, Reis H, Lemgruber L, Luko K, Wilkes J, Butter F, McCulloch R, Janzen CJ. Genome maintenance functions of a putative Trypanosoma brucei translesion DNA polymerase include telomere association and a role in antigenic variation. Nucleic Acids Res 2020; 48:9660-9680. [PMID: 32890403 PMCID: PMC7515707 DOI: 10.1093/nar/gkaa686] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 08/03/2020] [Accepted: 09/03/2020] [Indexed: 12/17/2022] Open
Abstract
Maintenance of genome integrity is critical to guarantee transfer of an intact genome from parent to offspring during cell division. DNA polymerases (Pols) provide roles in both replication of the genome and the repair of a wide range of lesions. Amongst replicative DNA Pols, translesion DNA Pols play a particular role: replication to bypass DNA damage. All cells express a range of translesion Pols, but little work has examined their function in parasites, including whether the enzymes might contribute to host-parasite interactions. Here, we describe a dual function of one putative translesion Pol in African trypanosomes, which we now name TbPolIE. Previously, we demonstrated that TbPolIE is associated with telomeric sequences and here we show that RNAi-mediated depletion of TbPolIE transcripts results in slowed growth, altered DNA content, changes in cell morphology, and increased sensitivity to DNA damaging agents. We also show that TbPolIE displays pronounced localization at the nuclear periphery, and that its depletion leads to chromosome segregation defects and increased levels of endogenous DNA damage. Finally, we demonstrate that TbPolIE depletion leads to deregulation of telomeric variant surface glycoprotein genes, linking the function of this putative translesion DNA polymerase to host immune evasion by antigenic variation.
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Affiliation(s)
- Andrea Zurita Leal
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Marie Schwebs
- Department of Cell & Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Emma Briggs
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Nadine Weisert
- Department of Cell & Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Helena Reis
- Department of Cell & Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Leandro Lemgruber
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Katarina Luko
- Quantitative Proteomics, Institute of Molecular Biology (IMB), Mainz, Germany
| | - Jonathan Wilkes
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Falk Butter
- Quantitative Proteomics, Institute of Molecular Biology (IMB), Mainz, Germany
| | - Richard McCulloch
- The Wellcome Centre for Integrative Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Christian J Janzen
- Department of Cell & Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
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Rose E, Carvalho JL, Hecht M. Mechanisms of DNA repair in Trypanosoma cruzi: What do we know so far? DNA Repair (Amst) 2020; 91-92:102873. [PMID: 32505694 DOI: 10.1016/j.dnarep.2020.102873] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/27/2020] [Accepted: 05/22/2020] [Indexed: 12/13/2022]
Abstract
Trypanosoma cruzi is the etiological agent of Chagas Disease, which affects 6-7 million people worldwide. Since the early stages of infection and throughout its life cycle, the parasite is exposed to several genotoxic agents. Furthermore, DNA damage is also part of the mechanism of action of at least a few trypanocidal drugs, including Benznidazole. Thus, it is paramount for the parasite to count on an efficient DNA repair machinery to guarantee genome integrity and survival. The present work provides an up-to-date review of both the conserved and peculiar DNA repair mechanisms described in T. cruzi against oxidative stress, ultraviolet and ionizing radiation, DNA adduct-inducing agents, and Benznidazole. The comprehension of the DNA repair mechanisms of the parasite may shed light on the parasite evolution and possibly pave the way for the development of novel and more effective trypanocidal drugs.
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Affiliation(s)
- Ester Rose
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasília, Brasília, Brazil.
| | - Juliana Lott Carvalho
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasília, Brasília, Brazil; Genomic Sciences and Biotechnology Program, Catholic University of Brasília, Brasília, Brazil
| | - Mariana Hecht
- Interdisciplinary Laboratory of Biosciences, Faculty of Medicine, University of Brasília, Brasília, Brazil
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Nunes VS, Moretti NS, da Silva MS, Elias MC, Janzen CJ, Schenkman S. Trimethylation of histone H3K76 by Dot1B enhances cell cycle progression after mitosis in Trypanosoma cruzi. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118694. [PMID: 32151656 DOI: 10.1016/j.bbamcr.2020.118694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 03/03/2020] [Accepted: 03/05/2020] [Indexed: 12/11/2022]
Abstract
Dot1 enzymes are histone methyltransferases that mono-, di- and trimethylate lysine 79 of histone H3 to affect several nuclear processes. The functions of these different methylation states are still largely unknown. Trypanosomes, which are flagellated protozoa that cause several parasitic diseases, have two Dot1 homologues. Dot1A catalyzes the mono- and dimethylation of lysine 76 during late G2 and mitosis, and Dot1B catalyzes trimethylation, which is a modification found in all stages of the cell cycle. Here, we generated Trypanosoma cruzi lines lacking Dot1B. Deletion of one allele resulted in parasites with increased levels of mono- and dimethylation and a reduction in H3K76me3. In the full knockout (DKO), no trimethylation was observed. Both the DKO and the single knockout (SKO) showed aberrant morphology and decreased growth due to cell cycle arrest after G2. This phenotype could be rescued by caffeine in the DKO, as caffeine is a checkpoint inhibitor of the cell cycle. The knockouts also phosphorylated γH2A without producing extensive DNA breaks, and Dot1B-depleted cells were more susceptible to general checkpoint kinase inhibitors, suggesting that a lack of H3K76 trimethylation prevents the initiation and/or completion of cytokinesis.
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Affiliation(s)
- Vinicius Santana Nunes
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, 04032-039 São Paulo, SP, Brazil; Centro de Ensino, Pesquisa e Inovação, Hospital Evangélico de Vila Velha, 29118-060 Vila Velha, ES, Brazil
| | - Nilmar Silvio Moretti
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, 04032-039 São Paulo, SP, Brazil
| | | | - Maria Carolina Elias
- Laboratório Especial de Ciclo Celular, Instituto Butantan, São Paulo, SP, Brazil
| | - Christian J Janzen
- Department of Cell & Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Sergio Schenkman
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, 04032-039 São Paulo, SP, Brazil.
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Lsm12 Mediates Deubiquitination of DNA Polymerase η To Help Saccharomyces cerevisiae Resist Oxidative Stress. Appl Environ Microbiol 2019; 85:AEM.01988-18. [PMID: 30366994 DOI: 10.1128/aem.01988-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 10/13/2018] [Indexed: 12/20/2022] Open
Abstract
In Saccharomyces cerevisiae, the Y family DNA polymerase η (Polη) regulates genome stability in response to different forms of environmental stress by translesion DNA synthesis. To elucidate the role of Polη in oxidative stress-induced DNA damage, we deleted or overexpressed the corresponding gene RAD30 and used transcriptome analysis to screen the potential genes associated with RAD30 to respond to DNA damage. Under 2 mM H2O2 treatment, the deletion of RAD30 resulted in a 2.2-fold decrease in survival and a 2.8-fold increase in DNA damage, whereas overexpression of RAD30 increased survival and decreased DNA damage by 1.2- and 1.4-fold, respectively, compared with the wild-type strain. Transcriptome and phenotypic analyses identified Lsm12 as a main factor involved in oxidative stress-induced DNA damage. Deleting LSM12 caused growth defects, while its overexpression enhanced cell growth under 2 mM H2O2 treatment. This effect was due to the physical interaction of Lsm12 with the UBZ domain of Polη to enhance Polη deubiquitination through Ubp3 and consequently promote Polη recruitment. Overall, these findings demonstrate that Lsm12 is a novel regulator mediating Polη deubiquitination to promote its recruitment under oxidative stress. Furthermore, this study provides a potential strategy to maintain the genome stability of industrial strains during fermentation.IMPORTANCE Polη was shown to be critical for cell growth in the yeast Saccharomyces cerevisiae, and deletion of its corresponding gene RAD30 caused a severe growth defect under exposure to oxidative stress with 2 mM H2O2 Furthermore, we found that Lsm12 physically interacts with Polη and promotes Polη deubiquitination and recruitment. Overall, these findings indicate Lsm12 is a novel regulator mediating Polη deubiquitination that regulates its recruitment in response to DNA damage induced by oxidative stress.
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8
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Rojas DA, Urbina F, Moreira-Ramos S, Castillo C, Kemmerling U, Lapier M, Maya JD, Solari A, Maldonado E. Endogenous overexpression of an active phosphorylated form of DNA polymerase β under oxidative stress in Trypanosoma cruzi. PLoS Negl Trop Dis 2018; 12:e0006220. [PMID: 29432450 PMCID: PMC5825160 DOI: 10.1371/journal.pntd.0006220] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 02/23/2018] [Accepted: 01/08/2018] [Indexed: 01/09/2023] Open
Abstract
Trypanosoma cruzi is exposed during its life to exogenous and endogenous oxidative stress, leading to damage of several macromolecules such as DNA. There are many DNA repair pathways in the nucleus and mitochondria (kinetoplast), where specific protein complexes detect and eliminate damage to DNA. One group of these proteins is the DNA polymerases. In particular, Tc DNA polymerase β participates in kinetoplast DNA replication and repair. However, the mechanisms which control its expression under oxidative stress are still unknown. Here we describe the effect of oxidative stress on the expression and function of Tc DNA polymerase β To this end parasite cells (epimastigotes and trypomastigotes) were exposed to peroxide during short periods of time. Tc DNA polymerase β which was associated physically with kinetoplast DNA, showed increased protein levels in response to peroxide damage in both parasite forms analyzed. Two forms of DNA polymerase β were identified and overexpressed after peroxide treatment. One of them was phosphorylated and active in DNA synthesis after renaturation on polyacrylamide electrophoresis gel. This phosphorylated form showed 3-4-fold increase in both parasite forms. Our findings indicate that these increments in protein levels are not under transcriptional control because the level of Tc DNA polymerase β mRNA is maintained or slightly decreased during the exposure to oxidative stress. We propose a mechanism where a DNA repair pathway activates a cascade leading to the increment of expression and phosphorylation of Tc DNA polymerase β in response to oxidative damage, which is discussed in the context of what is known in other trypanosomes which lack transcriptional control. Exposure of Trypanosome cruzi to oxidative stress leads to damage of several macromolecules such as DNA. DNA polymerases play a very important role in DNA repair after oxidative damage. One of them is Tc DNA polymerase β. In this work, two form of this DNA polymerase were identified and overexpressed in T. cruzi cells after hydrogen peroxide treatment been one of them a phosphorylated and highly active form. The increment of Tc DNA polymerase β was not correlated with changes in mRNA levels, indicating absence of transcriptional control. We propose a mechanism where hydrogen peroxide treatment activates a pathway leading to expression and phosphorylation of Tc DNA polymerase β in response to oxidative damage.
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Affiliation(s)
- Diego A. Rojas
- Microbiology and Micology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Fabiola Urbina
- Cellular and Molecular Biology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Sandra Moreira-Ramos
- Cellular and Molecular Biology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Christian Castillo
- Anatomy and Developmental Biology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Ulrike Kemmerling
- Anatomy and Developmental Biology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Michel Lapier
- Molecular and Clinical Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Juan Diego Maya
- Molecular and Clinical Pharmacology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Aldo Solari
- Cellular and Molecular Biology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Edio Maldonado
- Cellular and Molecular Biology Program, ICBM, Faculty of Medicine, University of Chile, Santiago, Chile
- * E-mail:
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Machado-Silva A, Cerqueira PG, Grazielle-Silva V, Gadelha FR, Peloso EDF, Teixeira SMR, Machado CR. How Trypanosoma cruzi deals with oxidative stress: Antioxidant defence and DNA repair pathways. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2016; 767:8-22. [DOI: 10.1016/j.mrrev.2015.12.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/22/2015] [Accepted: 12/23/2015] [Indexed: 02/06/2023]
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DNA repair pathways in trypanosomatids: from DNA repair to drug resistance. Microbiol Mol Biol Rev 2014; 78:40-73. [PMID: 24600040 DOI: 10.1128/mmbr.00045-13] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
All living organisms are continuously faced with endogenous or exogenous stress conditions affecting genome stability. DNA repair pathways act as a defense mechanism, which is essential to maintain DNA integrity. There is much to learn about the regulation and functions of these mechanisms, not only in human cells but also equally in divergent organisms. In trypanosomatids, DNA repair pathways protect the genome against mutations but also act as an adaptive mechanism to promote drug resistance. In this review, we scrutinize the molecular mechanisms and DNA repair pathways which are conserved in trypanosomatids. The recent advances made by the genome consortiums reveal the complete genomic sequences of several pathogens. Therefore, using bioinformatics and genomic sequences, we analyze the conservation of DNA repair proteins and their key protein motifs in trypanosomatids. We thus present a comprehensive view of DNA repair processes in trypanosomatids at the crossroads of DNA repair and drug resistance.
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Rajão MA, Furtado C, Alves CL, Passos-Silva DG, de Moura MB, Schamber-Reis BL, Kunrath-Lima M, Zuma AA, Vieira-da-Rocha JP, Garcia JBF, Mendes IC, Pena SDJ, Macedo AM, Franco GR, de Souza-Pinto NC, de Medeiros MHG, Cruz AK, Motta MCM, Teixeira SMR, Machado CR. Unveiling benznidazole's mechanism of action through overexpression of DNA repair proteins in Trypanosoma cruzi. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2014; 55:309-21. [PMID: 24347026 DOI: 10.1002/em.21839] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 11/22/2013] [Accepted: 11/24/2013] [Indexed: 05/14/2023]
Abstract
Benznidazole (BZ) is the most commonly used drug for the treatment of Chagas disease. Although BZ is known to induce the formation of free radicals and electrophilic metabolites within the parasite Trypanosoma cruzi, its precise mechanisms of action are still elusive. Here, we analyzed the survival of T. cruzi exposed to BZ using genetically modified parasites overexpressing different DNA repair proteins. Our results indicate that BZ induces oxidation mainly in the nucleotide pool, as heterologous expression of the nucleotide pyrophosphohydrolase MutT (but not overexpression of the glycosylase TcOgg1) increased drug resistance in the parasite. In addition, electron microscopy indicated that BZ catalyzes the formation of double-stranded breaks in the parasite, as its genomic DNA undergoes extensive heterochromatin unpacking following exposure to the drug. Furthermore, the overexpression of proteins involved in the recombination-mediated DNA repair increased resistance to BZ, reinforcing the idea that the drug causes double-stranded breaks. Our results also show that the overexpression of mitochondrial DNA repair proteins increase parasite survival upon BZ exposure, indicating that the drug induces lesions in the mitochondrial DNA as well. These findings suggest that BZ preferentially oxidizes the nucleotide pool, and the extensive incorporation of oxidized nucleotides during DNA replication leads to potentially lethal double-stranded DNA breaks in T. cruzi DNA.
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Affiliation(s)
- Matheus Andrade Rajão
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, UFMG, Belo Horizonte, Minas Gerais
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12
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Aguiar PHN, Furtado C, Repolês BM, Ribeiro GA, Mendes IC, Peloso EF, Gadelha FR, Macedo AM, Franco GR, Pena SDJ, Teixeira SMR, Vieira LQ, Guarneri AA, Andrade LO, Machado CR. Oxidative stress and DNA lesions: the role of 8-oxoguanine lesions in Trypanosoma cruzi cell viability. PLoS Negl Trop Dis 2013; 7:e2279. [PMID: 23785540 PMCID: PMC3681716 DOI: 10.1371/journal.pntd.0002279] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 04/29/2013] [Indexed: 01/09/2023] Open
Abstract
The main consequence of oxidative stress is the formation of DNA lesions, which can result in genomic instability and lead to cell death. Guanine is the base that is most susceptible to oxidation, due to its low redox potential, and 8-oxoguanine (8-oxoG) is the most common lesion. These characteristics make 8-oxoG a good cellular biomarker to indicate the extent of oxidative stress. If not repaired, 8-oxoG can pair with adenine and cause a G:C to T:A transversion. When 8-oxoG is inserted during DNA replication, it could generate double-strand breaks, which makes this lesion particularly deleterious. Trypanosoma cruzi needs to address various oxidative stress situations, such as the mammalian intracellular environment and the triatomine insect gut where it replicates. We focused on the MutT enzyme, which is responsible for removing 8-oxoG from the nucleotide pool. To investigate the importance of 8-oxoG during parasite infection of mammalian cells, we characterized the MutT gene in T. cruzi (TcMTH) and generated T. cruzi parasites heterologously expressing Escherichia coli MutT or overexpressing the TcMTH enzyme. In the epimastigote form, the recombinant and wild-type parasites displayed similar growth in normal conditions, but the MutT-expressing cells were more resistant to hydrogen peroxide treatment. The recombinant parasite also displayed significantly increased growth after 48 hours of infection in fibroblasts and macrophages when compared to wild-type cells, as well as increased parasitemia in Swiss mice. In addition, we demonstrated, using western blotting experiments, that MutT heterologous expression can influence the parasite antioxidant enzyme protein levels. These results indicate the importance of the 8-oxoG repair system for cell viability.
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Affiliation(s)
- Pedro H. N. Aguiar
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Carolina Furtado
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Bruno M. Repolês
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Grazielle A. Ribeiro
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Isabela C. Mendes
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Eduardo F. Peloso
- Departamento de Bioquímica, Instituto de Biologia - UNICAMP, Campinas, Sa˜o Paulo, Brazil
| | - Fernanda R. Gadelha
- Departamento de Bioquímica, Instituto de Biologia - UNICAMP, Campinas, Sa˜o Paulo, Brazil
| | - Andrea M. Macedo
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Glória R. Franco
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Sérgio D. J. Pena
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Santuza M. R. Teixeira
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Leda Q. Vieira
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | | | - Luciana O. Andrade
- Departamento de Morfologia, Instituto de Ciências Biológicas - UFMG, Belo Horizonte, Minas Gerais, Brazil
| | - Carlos R. Machado
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas - UFMG, Belo Horizonte, Minas Gerais, Brazil
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Furtado C, Kunrath-Lima M, Rajão MA, Mendes IC, de Moura MB, Campos PC, Macedo AM, Franco GR, Pena SDJ, Teixeira SMR, Van Houten B, Machado CR. Functional characterization of 8-oxoguanine DNA glycosylase of Trypanosoma cruzi. PLoS One 2012; 7:e42484. [PMID: 22876325 PMCID: PMC3411635 DOI: 10.1371/journal.pone.0042484] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 07/06/2012] [Indexed: 11/18/2022] Open
Abstract
The oxidative lesion 8-oxoguanine (8-oxoG) is removed during base excision repair by the 8-oxoguanine DNA glycosylase 1 (Ogg1). This lesion can erroneously pair with adenine, and the excision of this damaged base by Ogg1 enables the insertion of a guanine and prevents DNA mutation. In this report, we identified and characterized Ogg1 from the protozoan parasite Trypanosoma cruzi (TcOgg1), the causative agent of Chagas disease. Like most living organisms, T. cruzi is susceptible to oxidative stress, hence DNA repair is essential for its survival and improvement of infection. We verified that the TcOGG1 gene encodes an 8-oxoG DNA glycosylase by complementing an Ogg1-defective Saccharomyces cerevisiae strain. Heterologous expression of TcOGG1 reestablished the mutation frequency of the yeast mutant ogg1(-/-) (CD138) to wild type levels. We also demonstrate that the overexpression of TcOGG1 increases T. cruzi sensitivity to hydrogen peroxide (H(2)O(2)). Analysis of DNA lesions using quantitative PCR suggests that the increased susceptibility to H(2)O(2) of TcOGG1-overexpressor could be a consequence of uncoupled BER in abasic sites and/or strand breaks generated after TcOgg1 removes 8-oxoG, which are not rapidly repaired by the subsequent BER enzymes. This hypothesis is supported by the observation that TcOGG1-overexpressors have reduced levels of 8-oxoG both in the nucleus and in the parasite mitochondrion. The localization of TcOgg1 was examined in parasite transfected with a TcOgg1-GFP fusion, which confirmed that this enzyme is in both organelles. Taken together, our data indicate that T. cruzi has a functional Ogg1 ortholog that participates in nuclear and mitochondrial BER.
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Affiliation(s)
- Carolina Furtado
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Marianna Kunrath-Lima
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Matheus Andrade Rajão
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Isabela Cecília Mendes
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Michelle Barbi de Moura
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine and the University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Priscila Carneiro Campos
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Andrea Mara Macedo
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Glória Regina Franco
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Sérgio Danilo Junho Pena
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Santuza Maria Ribeiro Teixeira
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Bennett Van Houten
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine and the University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, Pennsylvania, United States of America
| | - Carlos Renato Machado
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- * E-mail:
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14
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Nicolay NH, Carter R, Hatch SB, Schultz N, Prevo R, McKenna WG, Helleday T, Sharma RA. Homologous recombination mediates S-phase-dependent radioresistance in cells deficient in DNA polymerase eta. Carcinogenesis 2012; 33:2026-34. [PMID: 22822095 DOI: 10.1093/carcin/bgs239] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
DNA polymerase eta (pol η) is the only DNA polymerase causally linked to carcinogenesis in humans. Inherited deficiency of pol η in the variant form of xeroderma pigmentosum (XPV) predisposes to UV-light-induced skin cancer. Pol η-deficient cells demonstrate increased sensitivity to cisplatin and oxaliplatin chemotherapy. We have found that XP30R0 fibroblasts derived from a patient with XPV are more resistant to cell kill by ionising radiation (IR) than the same cells complemented with wild-type pol η. This phenomenon has been confirmed in Burkitt's lymphoma cells, which either expressed wild-type pol η or harboured a pol η deletion. Pol η deficiency was associated with accumulation of cells in S-phase, which persisted after IR. Cells deficient in pol η demonstrated increased homologous recombination (HR)-directed repair of double strand breaks created by IR. Depletion of the HR protein, X-ray repair cross-complementing protein 3 (XRCC3), abrogated the radioresistance observed in pol η-deficient cells as compared with pol η-complemented cells. These findings suggest that HR mediates S-phase-dependent radioresistance associated with pol η deficiency. We propose that pol η protein levels in tumours may potentially be used to identify patients who require treatment with chemo-radiotherapy rather than radiotherapy alone for adequate tumour control.
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Affiliation(s)
- Nils H Nicolay
- Cancer Research UK-Medical Research Council Gray Institute for Radiation Oncology and Biology, Oncology Department, Old Road Campus Research Building, University of Oxford, Oxford OX3 7DQ, UK
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15
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Teixeira SM, El-Sayed NM, Araújo PR. The genome and its implications. ADVANCES IN PARASITOLOGY 2011; 75:209-30. [PMID: 21820558 DOI: 10.1016/b978-0-12-385863-4.00010-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Trypanosoma cruzi has a heterogeneous population composed of a pool of strains that circulate in the domestic and sylvatic cycles. Genome sequencing of the clone CL Brener revealed a highly repetitive genome of about 110Mb containing an estimated 22,570 genes. Because of its hybrid nature, sequences representing the two haplotypes have been generated. In addition, a repeat content close to 50% made the assembly of the estimated 41 pairs of chromosomes quite challenging. Similar to other trypanosomatids, the organization of T. cruzi chromosomes was found to be very peculiar, with protein-coding genes organized in long polycistronic transcription units encoding 20 or more proteins in one strand separated by strand switch regions. Another remarkable feature of the T. cruzi genome is the massive expansion of surface protein gene families. Because of the high genetic diversity of the T. cruzi population, sequencing of additional strains and comparative genomic and transcriptome analyses are in progress. Five years after its publication, the genome data have proven to be an essential tool for the study of T. cruzi and increasing efforts to translate this knowledge into the development of new modes of intervention to control Chagas disease are underway.
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Affiliation(s)
- Santuza M Teixeira
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
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16
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Zlatanou A, Despras E, Braz-Petta T, Boubakour-Azzouz I, Pouvelle C, Stewart GS, Nakajima S, Yasui A, Ishchenko AA, Kannouche PL. The hMsh2-hMsh6 complex acts in concert with monoubiquitinated PCNA and Pol η in response to oxidative DNA damage in human cells. Mol Cell 2011; 43:649-62. [PMID: 21855803 DOI: 10.1016/j.molcel.2011.06.023] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 04/01/2011] [Accepted: 06/08/2011] [Indexed: 11/29/2022]
Abstract
Posttranslational modification of PCNA by ubiquitin plays an important role in coordinating the processes of DNA damage tolerance during DNA replication. The monoubiquitination of PCNA was shown to facilitate the switch between the replicative DNA polymerase with the low-fidelity polymerase eta (η) to bypass UV-induced DNA lesions during replication. Here, we show that in response to oxidative stress, PCNA becomes transiently monoubiquitinated in an S phase- and USP1-independent manner. Moreover, Polη interacts with mUb-PCNA at sites of oxidative DNA damage via its PCNA-binding and ubiquitin-binding motifs. Strikingly, while functional base excision repair is not required for this modification of PCNA or Polη recruitment to chromatin, the presence of hMsh2-hMsh6 is indispensable. Our findings highlight an alternative pathway in response to oxidative DNA damage that may coordinate the removal of oxidatively induced clustered DNA lesions and could explain the high levels of oxidized DNA lesions in MSH2-deficient cells.
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Affiliation(s)
- Anastasia Zlatanou
- Group TLS Polymerases and Cancer, Université Paris-Sud, CNRS-UMR8200, Institut Gustave Roussy, 94800 Villejuif, France
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17
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Passos-Silva DG, Rajão MA, Nascimento de Aguiar PH, Vieira-da-Rocha JP, Machado CR, Furtado C. Overview of DNA Repair in Trypanosoma cruzi, Trypanosoma brucei, and Leishmania major. J Nucleic Acids 2010; 2010:840768. [PMID: 20976268 PMCID: PMC2952945 DOI: 10.4061/2010/840768] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 07/29/2010] [Accepted: 08/25/2010] [Indexed: 12/18/2022] Open
Abstract
A wide variety of DNA lesions arise due to environmental agents, normal cellular metabolism, or intrinsic weaknesses in the chemical bonds of DNA. Diverse cellular mechanisms have evolved to maintain genome stability, including mechanisms to repair damaged DNA, to avoid the incorporation of modified nucleotides, and to tolerate lesions (translesion synthesis). Studies of the mechanisms related to DNA metabolism in trypanosomatids have been very limited. Together with recent experimental studies, the genome sequencing of Trypanosoma brucei, Trypanosoma cruzi, and Leishmania major, three related pathogens with different life cycles and disease pathology, has revealed interesting features of the DNA repair mechanism in these protozoan parasites, which will be reviewed here.
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Affiliation(s)
- Danielle Gomes Passos-Silva
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, Pampulha, 31270-901 Belo Horizonte, MG, Brazil
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18
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Kashiwagi S, Kuraoka I, Fujiwara Y, Hitomi K, Cheng QJ, Fuss JO, Shin DS, Masutani C, Tainer JA, Hanaoka F, Iwai S. Characterization of a Y-Family DNA Polymerase eta from the Eukaryotic Thermophile Alvinella pompejana. J Nucleic Acids 2010; 2010. [PMID: 20936172 PMCID: PMC2945680 DOI: 10.4061/2010/701472] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Accepted: 06/29/2010] [Indexed: 11/20/2022] Open
Abstract
Human DNA polymerase η (HsPolη) plays an important role in translesion synthesis (TLS), which allows for replication past DNA damage such as UV-induced cis-syn cyclobutane pyrimidine dimers (CPDs). Here, we characterized ApPolη from the thermophilic worm Alvinella pompejana, which inhabits deep-sea hydrothermal vent chimneys. ApPolη shares sequence homology with HsPolη and contains domains for binding ubiquitin and proliferating cell nuclear antigen. Sun-induced UV does not penetrate Alvinella's environment; however, this novel DNA polymerase catalyzed efficient and accurate TLS past CPD, as well as 7,8-dihydro-8-oxoguanine and isomers of thymine glycol induced by reactive oxygen species. In addition, we found that ApPolη is more thermostable than HsPolη, as expected from its habitat temperature. Moreover, the activity of this enzyme was retained in the presence of a higher concentration of organic solvents. Therefore, ApPolη provides a robust, human-like Polη that is more active after exposure to high temperatures and organic solvents.
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Affiliation(s)
- Sayo Kashiwagi
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
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19
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Woodruff RV, Bomar MG, D'Souza S, Zhou P, Walker GC. The unusual UBZ domain of Saccharomyces cerevisiae polymerase η. DNA Repair (Amst) 2010; 9:1130-41. [PMID: 20837403 DOI: 10.1016/j.dnarep.2010.08.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 07/19/2010] [Accepted: 08/02/2010] [Indexed: 11/25/2022]
Abstract
Recent research has revealed the presence of ubiquitin-binding domains in the Y family polymerases. The ubiquitin-binding zinc finger (UBZ) domain of human polymerase η is vital for its regulation, localization, and function. Here, we elucidate structural and functional features of the non-canonical UBZ motif of Saccharomyces cerevisiae pol η. Characterization of pol η mutants confirms the importance of the UBZ motif and implies that its function is independent of zinc binding. Intriguingly, we demonstrate that zinc does bind to and affect the structure of the purified UBZ domain, but is not required for its ubiquitin-binding activity. Our finding that this unusual zinc finger is able to interact with ubiquitin even in its apo form adds support to the model that ubiquitin binding is the primary and functionally important activity of the UBZ domain in S. cerevisiae polymerase η. Putative ubiquitin-binding domains, primarily UBZs, are identified in the majority of known pol η homologs. We discuss the implications of our observations for zinc finger structure and pol η regulation.
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Affiliation(s)
- Rachel V Woodruff
- Department of Biology, Massachusetts Institute of Technology, Cambridge, 02139, USA
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