Nature Genetics
34, 326 - 329 (2003)
Published online: 8 June 2003; | doi:10.1038/ng1172
Cadmium is a mutagen that acts by inhibiting mismatch repairYong Hwan Jin1, Alan B Clark1, Robbert J C Slebos2, Hanan Al-Refai1, Jack A Taylor2, 3, Thomas A Kunkel1, Michael A Resnick1
& Dmitry A Gordenin11
Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA. 2
Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA. 3
Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
Correspondence should be addressed to Dmitry A Gordenin gordenin@niehs.nih.govMost errors that arise during DNA replication can be corrected by DNA polymerase proofreading or by post-replication mismatch repair (MMR). Inactivation of both mutation-avoidance systems results in extremely high mutability that can lead to error catastrophe1,
2. High mutability and the likelihood of cancer can be caused by mutations and epigenetic changes that reduce MMR3,
4. Hypermutability can also be caused by external factors that directly inhibit MMR. Identifying such factors has important implications for understanding the role of the environment in genome stability. We found that chronic exposure of yeast to environmentally relevant concentrations of cadmium, a known human carcinogen5, can result in extreme hypermutability. The mutation specificity along with responses in proofreading-deficient and MMR-deficient mutants indicate that cadmium reduces the capacity for MMR of small misalignments and base-base mismatches. In extracts of human cells, cadmium inhibited at least one step leading to mismatch removal. Together, our data show that a high level of genetic instability can result from environmental impediment of a mutation-avoidance system.
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