| When DNA is damaged, cells respond by activating specific repair mechanisms to fix the damage. To avoid propagation of this damage, they arrest progression through the cell cycle thereby allowing time for repair to occur. The pathway that leads to cell cycle arrest is the checkpoint activation cascade. Two processes, chromatin modification and DNA resection, mediate this cascade. Resection is slow in G1, producing minute amounts of single stranded DNA. This has contributed to the notion in the field that resection does not play a significant role in activating the checkpoint cascade in G1. This suggests that chromatin modification should be necessary and sufficient for checkpoint activation in G1. In addition to modification, chromatin dynamics also entails remodeling, which has been shown to function upstream of a key chromatin modification in the checkpoint activation cascade. Here I show that DNA resection is required for activation of the checkpoint cascade in G1. This reveals a previously unappreciated role for resection in G1. |
