ARF is also degraded which allows the damage signal to decline as the damaged DNA is repaired.
Therefore, once activated by the DNA damage signal, p53 blocks Cdc2-cyclin B kinase activity to prevent completely the entry of damaged chromosomes into mitosis.
Suzuki, M., Suzuki, K., Kodama, S., Yamashita, S. & Watanabe, M. Persistent amplification of DNA damage signal involved in replicative senescence of normal human diploid fibroblasts.
The model recapitulates the G2 delay observed in the biological response to varying levels of a DNA damage signal.
In most of these binucleate cells, the damaged nucleus arrested prior to spindle elongation, while the undamaged nucleus completed mitosis, even when the strength of the damage signal was increased.
We can see that ATM is the transductor gene for the DNA damage signal, which eventually activates p53 through inactivation of MDM2.
Next, we explored whether the DNA damage signal triggers the cell cycle checkpoint in mutant hair follicle stem cells.
Here, we demonstrated that treatment with cisplatin in fission yeast causes a Chk1-dependent DNA damage signal.
They observed that there was a time course associated with several of the protein levels related to the DNA damage signal transduction system [7].
In the experiments, authors indicate that the initial DNA damage signal induces ATM activation and recruitment, and results in early H2AX phosphorylation immediately adjacent to DSBs.
Ultraviolet (UV) irradiation and ionization radiation can fractionate the DNA double-stranded structure, and activate the p53 synthesis process that subsequently induces the DNA damage signal transduction system.
