Tamoxifen injections induce DNA damage response signaling in αMHC-MerCreMer mice.αMHC-MerCreMer+/+ mice received an injection of 60 μg/g body weight of tamoxifen on three consecutive days. Tamoxifen injections induce DNA damage response signaling in αMHC-MerCreMer mice.αMHC-MerCreMer+/+ mice received an injection of 60 μg/g body weight of tamoxifen on three consecutive days. Western blot analysis reveals an increase of γH2AX (A) and p53 (B) at various time points. Littermates injected with oil served as a negative control. Kevin Bersell et al. Dis. Model. Mech. 2013;6:1459-1469 © 2013. Published by The Company of Biologists Ltd