Abstract
Using Bacillus subtilis sacB gene expression system, mutation spectrum analysis of the radioresistant bacterium Deinococcus radiodurans was performed. The sacB encodes levansucrase that confers sucrose sensitivity when the gene is expressed in cytoplasm. Mutations in sacB, thereby, allow cells to grow in a medium containing sucrose. After acute exposure to gamma-rays, the sacB mutation frequency was readily increased. Whereas mutation spectrum after UV irradiation was similar to that of non-irradiated control, mutation spectrum after gamma-irradiation showed characteristic features; +1 frameshift at adenine cluster, and increased transposition frequency of an insertion sequence. These results suggest that D. radiodurans possesses mutagenesis mechanism that is activated through radiation-induced DNA damage. [J Radiat Res 44:414 (2003)]
