P53 and DNA Damage Repair
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Questions and Answers

What role does the activation of MYC (oncogene) play in relation to p53?

  • It exclusively triggers cell cycle progression
  • It inhibits p53's function in apoptosis
  • It destabilizes p53's interaction with gene promoters
  • It promotes p53's regulation towards apoptosis (correct)
  • Which mutation predominantly prevents the activation of p53?

  • BAX inactivation
  • MDM2 overexpression
  • FASR mutation
  • CHK2 mutation (correct)
  • Which of the following correctly describes the effect of viral proteins on p53 and RB?

  • They activate RB and inhibit cell division
  • They enhance the DNA binding of p53
  • They contribute to the inactivation of both p53 and RB (correct)
  • They stimulate mutations in the p53 gene
  • Which statement correctly identifies the consequence of p53 mutations in cancer?

    <p>They can lead to aberrant protein conformation and hinder DNA binding</p> Signup and view all the answers

    What is the primary effect of targeting the p53 pathway in cancer therapy?

    <p>To restore the function of mutated p53 proteins</p> Signup and view all the answers

    What is the primary function of the P53 protein in relation to cellular responses?

    <p>Regulating the cell cycle and inducing apoptosis under stress conditions</p> Signup and view all the answers

    Which of the following statements about Li-Fraumeni Syndrome is correct?

    <p>It is characterized by germline mutations of the TP53 gene, increasing cancer risk at a young age.</p> Signup and view all the answers

    What role does MDM2 play in the regulation of P53 protein?

    <p>It promotes the degradation of P53 and prevents its activation.</p> Signup and view all the answers

    Which pathway is primarily associated with the activation of P53 in response to DNA damage?

    <p>p53-ATM/ATR signaling pathway</p> Signup and view all the answers

    What type of mutation occurs as a result of misrepair by DNA polymerase on guanine (G)?

    <p>G to T transversion mutation</p> Signup and view all the answers

    Study Notes

    DNA Damage and Repair

    • DNA polymerase can misrepair guanine (G) leading to G->T transversion mutations.
    • P53 receives signals of DNA damage and increases its protein levels in response.

    P53: Guardian of the Genome

    • P53 interprets signals from the cell, and acts as a guardian against tumor formation.
    • P53 is a cellular hub that receives many signals.
    • P53 is important for:
      • Development
      • Blood cell formation
      • Cell death

    P53 and Cancer

    • Mice models lacking P53 spontaneously develop cancer.
    • Li-Fraumeni Syndrome
      • Germline mutation of TP53 gene
      • Increased risk of developing cancer at a young age
    • The P53 protein is significantly more abundant in mice compared to humans.

    P53 Function

    • P53 is a key regulator of aging.
    • P53 protein has a short half-life of 6-20 minutes, and its levels are regulated by MDM2.
    • P53 binds to DNA to activate or repress target genes.
    • P53 is regulated by MYC, an oncogene.

    P53 and Apoptosis

    • P53 can trigger apoptosis, a process of programmed cell death.
    • P53 can also trigger cell cycle arrest to allow for DNA repair.

    P53 Pathway Mutations

    • Mutations in CHK2 prevent activation of P53.
    • MDM2 overexpression leads to increased degradation of P53.
    • Missense mutations in the DNA binding domain of P53 can interfere with its function.

    Viral Inactivation of p53 and RB

    • Viral proteins can inactivate p53 and RB, two tumor suppressor proteins.
    • HPV (human papillomavirus) inserts its genome fragments (oncogene) into human DNA.
    • E6 and E7 viral proteins negatively regulate p53 and RB.

    Targeting the p53 Pathway

    • Small molecules can correct p53 mutations and help restore correct protein folding.
    • Activating endogenous p53 can prevent tumor development if p53 is not mutated.

    P53 and Oxidative Stress

    • P53 can reduce oxidative stress by increasing the expression of glutathione peroxidase 1 and sestrins.
    • Oxidative stress can lead to DNA oxidation, such as 8-oxoguanine.
    • By reducing oxidative stress, P53 can protect the genome from damage.

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    Description

    This quiz explores the role of the P53 protein in DNA damage repair and its significance in cancer prevention. It covers mechanisms of DNA damage, the regulation of P53, and its functions in apoptosis and aging. Test your understanding of P53 as the guardian of the genome and its links to cancer syndromes.

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