Lecture 3: DNA Damage and Repair

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What is the primary mechanism by which Cytochrome P-450 (Cyp) enzymes contribute to DNA damage?

Direct interaction with DNA to cause mutations

Detoxification of carcinogens through oxidation

Conversion of chemically inert pro-carcinogens into ultimate carcinogens (correct)

Activation of DNA repair mechanisms

What is the primary consequence of DNA damage caused by UV radiation?

Point mutations due to base deamination

Covalent cross-links between adjacent pyrimidine bases (correct)

ROS-mediated oxidation of bases

Formation of DNA adducts

What is the primary function of p53 in response to DNA damage?

Cell cycle arrest (correct)

DNA replication

Transcriptional activation of DNA repair genes

Cellular apoptosis

What is the characteristic of p53 mutations detected in most common cancers?

Missense mutations in the DNA binding domain Signup and view all the answers

What is the consequence of loss of the remaining wild-type allele in p53 mutations?

Further advantage conferred to the cell Signup and view all the answers

What is the primary function of DNA glycosylase enzymes in DNA repair?

Excision of damaged bases Signup and view all the answers

What is the primary function of Base Excision Repair (BER)?

Repairing endogenous DNA damage caused by reactive oxygen species Signup and view all the answers

Which DNA repair mechanism is responsible for repairing damage caused by UV light and X-rays?

Nucleotide Excision Repair (NER) Signup and view all the answers

What is the role of DNA glycosylase enzymes in Base Excision Repair (BER)?

Cleaving recognition sites for APE Signup and view all the answers

What is the consequence of inherited defects in DNA repair genes?

Inherited cancer susceptibility Signup and view all the answers

What is the purpose of checkpoint proteins in DNA repair?

To initiate DNA repair Signup and view all the answers

How do chemotherapy agents target cancer cells?

By integrating into DNA of fast dividing cells Signup and view all the answers

What is the estimated number of errors/mutations that occur per person per day due to DNA damage or during division?

~2x10^18 Signup and view all the answers

Which type of DNA repair mechanism is responsible for correcting damage caused by ultraviolet light?

Nucleotide Excision Repair (NER) Signup and view all the answers

What is the role of APOBECs in the context of DNA damage and repair?

They are a family of cytidine deaminases that protect against retroviral and retrotransposon infection Signup and view all the answers

What is the consequence of 8-oxo-dG mis-base pairing with deoxyadenosine during DNA replication?

C to A transversion Signup and view all the answers

What is the primary function of checkpoint proteins in the context of DNA damage and repair?

To arrest the cell cycle and allow for DNA repair Signup and view all the answers

What is the relevance of DNA repair mechanisms in the development and treatment of cancer?

DNA repair mechanisms are involved in both the development and treatment of cancer Signup and view all the answers