Instead of adding PDGF, you induce DNA damage by irradiating the cells with UV l
ID: 69719 • Letter: I
Question
Instead of adding PDGF, you induce DNA damage by irradiating the cells with UV light. You observe that the activity of ATM kinase is present with UV light and absent without it, p21CIP binds to CDK in the presence of UV light and is seperate without it & the level of Y15 phosphorylated constituatively zero. Which of the following pertains to these cells?
A. Cells activated the p53-independent DNA damage checkpoint and repaired the damage.
B. Cells activated the p53-dependent DNA damage checkpoint and repaired the damage.
C. Cells activated the p53-independent DNA damage checkpoint and did not repair the damage.
D. Cells activated the p53-dependent DNA damage checkpoint and did not repair the damage.
E. Cells are in Mitosis & have activated the Mitotic Spindle Checkpoint.
Explanation / Answer
E. Cells are in Mitosis & have activated the Mitotic Spindle Checkpoint.
(Though above pathwaysays UV induced DNA damage activates ATM which in turn activates p53 by serine phosphorylation. p53 induces the expression of p21-CIP which is inhibitor of CDK activity. However, dephodphorylation status of CDK at Y15 implies that cells are in mitosis).