Answer to Question #60246 in Genetics for Sanjukta Ghosh
''A major function of p53 is to protect the genome from harmful mutations, that is, to prevent genetic instability, justifying the name “guardian of the genome.”- how does it actually protect the genome from harmful mutation and why is it called the guardian of the genome? Please explain
Special systems detect damage in DNA and activate certain kinases, which phosphorylate p53, and thus, activate it. Activated p53 serves as transcription factor for certain genes, most of them encode for DNA repair enzymes. P53 binds to DNA and contributes to the expression of those proteins. Thus, DNA repair starts. In addition, it stimulates the expression of the own gene, resulting in the increase in the number of its own copies. P53 can be alternatively activated by ultraviolet rays, which cause mutations in DNA. If the number of mutations in DNA is extremely high, they cannot be repaired. Thus, p53 accumulates in high amounts and initiates apoptosis, which prevents the cell from becoming tumor. Finally, p53 regulates the cell cycle. It does not allow the cell to pass to mitosis of any mistakes are identified at G1 or S stage of interphase.