AP BIOLOGY

Detailed explanation-1: -p53 is involved in almost all nuclear DNA repair pathways including BER, NER, MMR, NHEJ and HR [32]. The transcription-independent functions play a prominent role as a facilitator of DNA repair by halting the cell cycle to allow time for the repair machineries to restore genome stability [25].

Detailed explanation-2: -Other lesions in DNA and indeed additional stressful events to the cell lead to the activation of several protein kinases including ATR, JNK, c-Abl, PI3 kinase and Akt, all of which influence the state of stability and activity of p53.

Detailed explanation-3: -Activation of p53 can occur in response to a number of cellular stresses, including DNA damage, hypoxia and nucleotide deprivation.

Detailed explanation-4: -p53 is a potent activator of genes involved in cellular senescence, such as p21 and PAI-1, and p53-dependent activation of these genes has been shown to be a physiological, in vivo response to DNA damage events [35, 57–60].

Detailed explanation-5: -A gene that makes a protein that is found inside the nucleus of cells and plays a key role in controlling cell division and cell death. Mutations (changes) in the p53 gene may cause cancer cells to grow and spread in the body.