DNA DamageDNA RepairUltraviolet RaysOxidative StressTumor Suppressor Protein p53ApoptosisReactive Oxygen SpeciesDNAComet AssayTime FactorsAtaxia Telangiectasia Mutated ProteinsCell Cycle ProteinsDeoxyguanosineCheckpoint Kinase 2DNA-Binding ProteinsDNA Breaks, Double-StrandedProtein-Serine-Threonine KinasesCell CycleTumor Suppressor ProteinsGamma RaysMethyl MethanesulfonateHistonesMutagensNuclear ProteinsGenomic InstabilityG2 PhaseDNA Replication