Data/hora: 01/06/2024 18:27:08

Provedor de dados: | Institutional Archive of Ifreme (ArchiMer)
País: | France
Título: | Oxidative DNA damage and repair in the radioresistant archaeon Thermococcus gammatolerans.
Autores: | Barbier, Ewa; Lagorce, Arnaud; Hachemi, Amine; Dutertre, Murielle; Gorlas, Aurore; Morand, Lucie; Saint-pierre, Christine; Ravanat, Jean-luc; Douki, Thierry; Armengaud, Jean; Gasparutto, Didier; Confalonieri, Fabrice; Breton, Jean.
Data: | 2016-11
Ano: | 2016
Resumo: | The hyperthermophilic archaeon Thermococcus gammatolerans can resist huge doses of γ-irradiation – up to 5.0 kGy – without loss of viability. The potential to withstand such harsh conditions is probably due to complementary passive and active mechanisms, including repair of damaged chromosomes. In this work, we documented the formation and repair of oxidative DNA lesions in T. gammatolerans. The basal level of the oxidized nucleoside, 8-oxo-2′-deoxyguanosine (8-oxo-dGuo), was established at 9.2 (+/- 0.9) 8-oxo-dGuo per 106 nucleosides, a higher level than those usually measured in eukaryotic cells or bacteria. A significant increase in oxidative damage, i.e. up to 24.2 (+/- 8.0) 8-oxo-dGuo/106 nucleosides, was measured for T .gammatolerans exposed to a 5.0 kGy dose of γ-rays. Surprisingly, the yield of radiation-induced modifications was lower than those previously observed for human cells exposed to doses corresponding to a few grays. One hour after irradiation, 8-oxo-dGuo levels were significantly reduced, indicating an efficient repair. Two putative base excision repair (BER) enzymes, TGAM_1277 and TGAM_1653, were demonstrated both by proteomics and transcriptomics to be present in the cells without exposure to ionizing radiation. Their transcripts were moderately upregulated after gamma irradiation. After heterologous production and purification of these enzymes, biochemical assays based on electrophoresis and MALDI-TOF (Matrix-Assisted Laser Desorption Ionization – Time Of Flight) mass spectrometry indicated that both have a β-elimination cleavage activity. TGAM_1653 repairs 8-oxo-dGuo whereas TGAM_1277 is also able to remove lesions affecting pyrimidines (1-[2-deoxy-β-D-erythro-pentofuranosyl]-5-hydroxyhydantoin (5-OH-dHyd) and 1-[2-deoxy-β-D-erythro-pentofuranosyl]-5-hydroxy-5-methylhydantoin (5-OH-5-Me-dHyd)). This work showed that, in normal growth conditions or in the presence of a strong oxidative stress, T. gammatolerans has the potential to rapidly reduce the extent of DNA oxidation, with at least these two BER enzymes as bodyguards with distinct substrate ranges.
Tipo: | Text
Idioma: | Inglês

Identificador:

https://archimer.ifremer.fr/doc/00353/46388/46015.pdf

DOI:10.1021/acs.chemrestox.6b00128

https://archimer.ifremer.fr/doc/00353/46388/

Editor: | Amer Chemical Soc
Formato: | application/pdf
Fonte: | Chemical Research In Toxicology (0893-228X) (Amer Chemical Soc), 2016-11 , Vol. 29 , N. 11 , P. 1796-1809

Fonte:

2016 American Chemical Society

info:eu-repo/semantics/openAccess

restricted use