article 4 cell mutant 4 controlled study 4 nonhuman 4 priority journal 4 4 aminobutyric acid 2 5 aminolevulinate synthase 2 Animals 2 Biological Markers 2 CHO Cells 2 CHO cell 2 Catalytic subunits 2 Cell culture 2 Chinese Hamster ovary cells 2 Cricetinae 2 Cricetulus 2 DNA 2 DNA Breaks, Double-Stranded 2 DNA Repair 2 DNA damage 2 DNA double-strand breaks 2 DNA end joining repair 2 DNA-Activated Protein Kinase 2 DNA-dependent protein kinase 2 Double-strand breaks 2 Enzymes 2 Eukaryota 2 Gamma Rays 2 High linear energy transfers 2 Histones 2