Fig. 4

Prolonged MTA pretreatment enhances irradiation-induced accumulation of persistent DNA damage. Basal H2AX phosphorylation was set at ~10 % in untreated controls and used for normalization among experiments as described in the “Methods” section. a H2AX phosphorylation levels of the whole population were determined as described in Additional file 4: Figure S4. b Cell cycle phase-specific H2AX phosphorylation levels were determined by combining the γH2AX-positive and γH2AX-negative gates (Additional file 4: Figure S4) with the gates to determine the specific cell cycle phases (Additional file 3: Figure S3). Data shown are the mean values and standard deviations of three independent experiments. neg γH2AX-negative, pos γH2AX-positive