Proteomic and cellular responses against mutagenesis

ABSTRACT: Endogenous stress represents a major source of genome instability, but is in essence difficult to apprehend. Incorporation of labeled radionuclides into DNA constitutes a tractable model to analyze cellular responses to endogenous attacks. Here we show that incorporation of [3H]thymidine into CHO hamster cells generates oxidative-induced mutagenesis, but, with a peak at low doses. Proteomic analysis showed that the cellular global response differs between low and high levels of endogenous stress. In particular, these results confirmed the involvement of proteins implicated in redox homeostasis and DNA damage signaling pathways. Induced-mutagenesis was abolished by the anti-oxidant N-acetyl cysteine and plateaued, at high doses, upon exposure to L-buthionine sulfoximine, which represses cellular detoxification. The [3H]thymidine-induced mutation spectrum revealed mostly base substitutions, exhibiting a signature specific for low doses (GC>CG and AT>CG). Consistently, the enzymatic activity of the base excision repair protein APE-1 is induced at only medium or high doses. Collectively, the data reveal that a threshold of endogenous stress must be reached to trigger cellular detoxification and DNA repair programs; below this threshold, the consequences of endogenous stress escape cellular surveillance, leading to high levels of mutagenesis. Therefore, low doses of endogenous local stress can jeopardize genome integrity more efficiently than higher doses.

INSTRUMENT(S):

ORGANISM(S): Cricetulus Griseus (chinese Hamster) (cricetulus Barabensis Griseus)

TISSUE(S): Permanent Cell Line Cell, Cell Culture

DISEASE(S): Malignant Neoplasm Of Ovary

SUBMITTER: sonia hem  

LAB HEAD: Bernard S. Lopez

PROVIDER: PXD003542 | Pride | 2016-07-15

REPOSITORIES: Pride