Reduction of 8-oxodGTP in the nucleotide pool by hMTH1 leads to reduction in mutations in the human lymphoblastoid cell line TK6 exposed to UVA
2011 (English)In: Mutation research, ISSN 0027-5107, E-ISSN 1873-135X, Vol. 715, no 1-2, 13-18 p.Article in journal (Refereed) Published
UVA has been suggested to play an important role in UV-induced mutagenesis. The mechanisms by which UVA induces mutations are still a matter of debate. Our aim was to investigate the protective capacity of hMTH1, a nucleotide pool sanitization enzyme with 8-oxodGTPase activity. Human B lymphoblastoid cells were stably transfected with shRNA directed against hMTH1. Clonogenic survival, mutations, intracellular and extracellular levels of 8-oxodG (8-oxo-7, 8-dihydro-2'-deoxyguanosine) and dG in the nucleotide pool of UVA-irradiated transfected and non-transfected cells were investigated. Mutations were determined in the thymidine kinase locus. Intracellular 8-oxodG and dG were measured using a modified ELISA and HPLC, respectively, after extraction of the nucleotide pool and conversion of nucleotides to their corresponding nucleosides. 8-oxodG in the medium was measured using ELISA. UVA-induced mutations were significantly higher while the survival was slightly lower in transfected compared to non-transfected cells. The increased mutation rate in transfected cells at increased exposure correlated with enhanced levels of 8-oxodG in the nucleotide pool, and a somewhat reduced level of 8-oxodG in the medium. The results indicate that the nucleotide pool is a significant target for UVA-induced mutations and implicates that hMTH1 plays an important role in protecting cells from UVA-induced oxidative stress.
Place, publisher, year, edition, pages
2011. Vol. 715, no 1-2, 13-18 p.
Oxidative stress, hMTH1, Mutagenesis, UVA, 8-oxo-dG, 8-OH-dG, 8-oxo-dGTP, Reactive oxygen species
Research subject Molecular Genetics
IdentifiersURN: urn:nbn:se:su:diva-66540DOI: 10.1016/j.mrfmmm.2011.07.005ISI: 000295664200003OAI: oai:DiVA.org:su-66540DiVA: diva2:469784
authorCount :82011-12-272011-12-202015-02-26Bibliographically approved