Augmented oxidative stress increases 8-oxoguanine preferentially in the transcriptionally active genomic regions

Summary

8-Oxoguanine (8-oxoG) is the most common DNA base modification in the mammalian genome, associated with oxidative stress. Here we analysed the alterations in the distribution of 8-oxoG across the entire murine genome, before and after an elevation of oxidative stress by the use of ferric nitrilotriacetate (Fe-NTA) as an oxidative stress inducer in the renal proximal tubules. We isolated DNA fragments containing 8-oxoGs with immunoprecipitation from the murine genome, and amplified them by PCR for a distribution analysis with microarray-based comparative genomic hybridisation. The distribution profiles revealed that frequencies of 8-oxoG fluctuated with a cycle of 1-10 Mb along the chromosomes and the amplitude of the fluctuation was reduced after Fe-NTA administration. The distributions of