title: Functional characterization of 8-oxoguanine DNA glycosylase of Trypanosoma cruzi.
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.
authors.affiliation: Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Furtado
authors.forename: Marianna
authors.initials: M
authors.lastname: Kunrath-Lima
authors.forename: Matheus Andrade
authors.initials: MA
authors.lastname: Rajão
authors.forename: Isabela Cecília
authors.initials: IC
authors.lastname: Mendes
authors.forename: Michelle Barbi
authors.initials: MB
authors.lastname: de Moura
authors.forename: Priscila Carneiro
authors.initials: PC
authors.lastname: Campos
authors.forename: Andrea Mara
authors.initials: AM
authors.lastname: Macedo
authors.forename: Glória Regina
authors.initials: GR
authors.lastname: Franco
authors.forename: Sérgio Danilo Junho
authors.initials: SD
authors.lastname: Pena
authors.forename: Santuza Maria Ribeiro
authors.initials: SM
authors.lastname: Teixeira
authors.forename: Bennett
authors.initials: B
authors.lastname: Van Houten
authors.forename: Carlos Renato
authors.initials: CR
authors.lastname: Machado
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects; D045647:DNA Glycosylases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D005816:Genetic Complementation Test; D054629:Genome, Mitochondrial; D018503:Genome, Protozoan; D006147:Guanine / Q000031:analogs & derivatives* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008969:Molecular Sequence Data; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014349:Trypanosoma cruzi / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics
chemical_list: C024829:8-hydroxyguanine; D006147:Guanine; D006861:Hydrogen Peroxide; D045647:DNA Glycosylases