Overexpression of hOGG1 protein enhanced the sensitivity to killing by gamma-rays in HeLa cells

Abstract

It's well-known that low LET ionizing radiation, such as X-rays and gamma-rays, produces a unique form of DNA damage called "clustered damages", which is two or more lesions induced within the one or two helical turns of the DNA. E. coli mutM nth nei triple mutants were less sensitive to gamma-rays and X-rays than wild-type strain. The triple mutant with plasmid bearing mutM gene was more sensitive than wild-type. On the other hand, the triple mutants showed higher sensitivity to H₂O₂ than wild-type. Clustered damages formed by ionizing radiation might be converted to lethal DSB during attempted base excision repair. Recently we found that overexpression of hOGG1 also enhanced the sensitivity to gamma-rays in E. coli. In this report we showed HeLaS3 cells transfected by hOGG1 type1a plasmid was more sensitive to gamma-rays than HeLaS3 cells without plasmid. We are now studying the biological effects of clustered damages in human cells. [J Radiat Res 44:440 (2003)]