Nucleotide excision repair

Definition

Nucleotide excision repair (NER) is a DNA repair mechanism that removes damaged sections of DNA, specifically those caused by UV radiation and chemical exposure. This process involves the recognition of distortions in the DNA helix, excision of the damaged nucleotides, and subsequent synthesis of new DNA to fill the gap. NER is crucial for maintaining genomic stability, especially in response to plasma-induced DNA damage, which can lead to mutations if not properly repaired.

5 Must Know Facts For Your Next Test

1. NER involves multiple steps: damage recognition, strand separation, excision of the damaged nucleotides, and DNA synthesis to fill in the gap.
2. This repair mechanism is essential for fixing bulky lesions in DNA that disrupt normal base pairing and can be caused by environmental factors like UV light.
3. Nucleotide excision repair operates through a coordinated effort of various proteins, including endonucleases that cut the DNA strand around the damage.
4. Deficiencies in NER can lead to severe consequences, such as increased susceptibility to skin cancer due to the accumulation of unrepaired DNA lesions.
5. In addition to UV-induced damage, NER also repairs certain types of chemical adducts formed by environmental toxins, highlighting its role in cellular protection.

Review Questions

• How does nucleotide excision repair identify and remove damaged DNA segments?
  • Nucleotide excision repair identifies damaged DNA segments by recognizing distortions in the DNA helix caused by lesions such as those from UV radiation. Specialized proteins scan the DNA for these irregularities, triggering a series of events that involve unwinding the DNA, cutting out the damaged nucleotides, and using the undamaged strand as a template to synthesize new DNA. This process is crucial for maintaining the integrity of the genome.
• Discuss the consequences of impaired nucleotide excision repair mechanisms in humans.
  • Impaired nucleotide excision repair can lead to serious health issues, notably xeroderma pigmentosum, where individuals have a heightened sensitivity to sunlight due to their inability to repair UV-induced DNA damage. The accumulation of unrepaired lesions can result in mutations that lead to various cancers, particularly skin cancer. This highlights the importance of NER in protecting against environmental threats and ensuring cellular health.
• Evaluate the role of nucleotide excision repair in plasma medicine applications and its implications for therapeutic strategies.
  • Nucleotide excision repair plays a critical role in plasma medicine applications by addressing plasma-induced DNA damage that can arise during therapeutic treatments. The effectiveness of therapies utilizing plasma technology relies on efficient NER mechanisms to mitigate potential harmful effects on healthy cells. By enhancing our understanding of how NER operates, researchers can develop targeted strategies that improve treatment outcomes while minimizing damage to normal tissue, ultimately leading to safer and more effective plasma-based therapies.

Related terms

DNA damage: Alterations to the chemical structure of DNA that can affect its integrity and function, often resulting from environmental factors like UV light or chemicals.

repair mechanisms: Biological processes that fix damaged DNA to prevent mutations and maintain cellular health, including base excision repair and homologous recombination.

xeroderma pigmentosum: A genetic disorder caused by a deficiency in nucleotide excision repair, leading to extreme sensitivity to UV radiation and a higher risk of skin cancer.