Cell CycleG2 Phase Cell Cycle CheckpointsS Phase Cell Cycle CheckpointsG1 Phase Cell Cycle CheckpointsCell Cycle ProteinsCell Line, TumorM Phase Cell Cycle CheckpointsCell ProliferationApoptosisCell Cycle CheckpointsG2 PhaseS PhaseG1 PhaseDNA DamageCheckpoint Kinase 2MitosisCell DivisionProtein-Serine-Threonine KinasesTumor Suppressor Protein p53Genes, cdcAtaxia Telangiectasia Mutated ProteinsTumor Cells, CulturedSignal TransductionPhosphorylationCyclin-Dependent Kinase Inhibitor p21DNA-Binding ProteinsTumor Suppressor ProteinsCyclinsCell LineCell SurvivalProtein KinasesFlow Cytometrycdc25 PhosphatasesCells, CulturedDNA RepairCDC2 Protein KinaseNuclear ProteinsDNA ReplicationCyclin B1Retinoblastoma ProteinMutationGamma RaysAntineoplastic AgentsMolecular Sequence DataBlotting, WesternHeLa CellsFibroblastsCyclin-Dependent Kinase Inhibitor p27Models, BiologicalG0 PhaseCyclin BCyclin D1RNA, Small InterferingCyclin-Dependent Kinase 2HydroxyureaRadiation, IonizingRNA, MessengerTime FactorsRadiation ToleranceAtaxia TelangiectasiaTransfectionGene Expression Regulation, NeoplasticCyclin ESpindle ApparatusTranscription FactorsEndoreduplicationAmino Acid SequenceCell NucleusCyclin-Dependent KinasesDown-RegulationDNACell DifferentiationGene Expression RegulationNeoplasmsDose-Response Relationship, DrugImmunohistochemistryCyclin-Dependent Kinase 4Saccharomyces cerevisiae ProteinsUltraviolet RaysGenomic InstabilitySaccharomyces cerevisiaeEnzyme ActivationNeoplasm ProteinsAntineoplastic Agents, PhytogenicBase SequenceProto-Oncogene ProteinsEnzyme InhibitorsTranscription, GeneticNocodazoleHistonesCaspasesGene ExpressionProtein BindingSchizosaccharomycesGenes, p53Proto-Oncogene Proteins c-bcl-2Mice, Inbred C57BLReverse Transcriptase Polymerase Chain ReactionRNA InterferenceCaspase 3