Study of a fast, convenient and sensitive genotoxicity test utilizing cells lacking DNA damage response factors

2014 Fiscal Year Final Research Report

• Project/Area Number: 25650124
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Genetics/Chromosome dynamics
• Research Institution: National Institute of Health Sciences
• Principal Investigator: AKAGI Jun-ichi 国立医薬品食品衛生研究所, 病理部, 研究員 (60512556)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 損傷乗り越え複製 / 遺伝毒性試験

Outline of Final Research Achievements

Genotoxicity of environmental chemicals mainly arise from modifications of genomic DNA, such as alkylation, oxidation and adduct formation. Majority of point mutations in genomic DNA are considered to be caused as the consequence of translesion synthesis (TLS) that allows direct replication past DNA lesions. On the other hand, when TLS fails, cell survival is severely affected as a result of replication fork collapse. We have analyzed the triple knockout (TKO) mouse embryonic fibroblasts lacking three TLS DNA polymerases, Polη, Polι and Polκ. The TKO cells showed increased sensitivity to various genotoxins compared to the wild-type cells. The IC50WT/IC50TKO ratios that represent the difference of cellular sensitivity between TKO cells and the wild-type cells in 10 out of 11 genotoxins were more than 2, while that in 6 nongenotoxins were less than 2.0. Thus, the hypersensitivity of TKO cells to genotoxins is useful to evaluate genotoxicity of chemicals.

Free Research Field

分子細胞生物学