Often an extreme change in a cell’s environment activates the expression of a set of genes whose protein products protect the cell from the deleterious effects of this change.
Cells also have mechanisms that elevate the levels of DNA repair enzymes, as an emergency response to severe DNA damage.
What does DNA repair do?
DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome.
What can xeroderma pigmentosum tell us about how DNA damage is repaired?
Xeroderma pigmentosum (XP) is a rare, inherited disorder characterized by extreme skin sensitivity to ultraviolet (UV) rays from sunlight. XP is caused by mutations in genes involved in nucleotide excision repair (NER) of damaged DNA. XP patients have more than a 10,000-fold increased risk of developing skin cancer.
What causes DNA damage?
DNA can be damaged via environmental factors as well. Environmental agents such as UV light, ionizing radiation, and genotoxic chemicals. Replication forks can be stalled due to damaged DNA and double strand breaks are also a form of DNA damage.
What are the types of DNA repair?
There are three modes of excision repair, each of which employs specialized sets of enzymes.
- Base Excision Repair (BER)
- Nucleotide Excision Repair (NER)
- Mismatch Repair (MMR)
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