Nucleotide excision repair

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On damage to a single strand of the DNA double helix the mammalian repair mechanism involves[1] :

  1. Formation of a repair complex
    • This contains TFIIH, XPA, XPC-R23, PRA, XPG and ERCC1-XPF proteins with the availability/activity of the last being the classic rate limiting step.
  2. The complex unwinds the DNA forming a bubble
  3. The endonuclease XPG protein excises the damaged portion on the 3' side
  4. The endonuclease ERCC1-XPF protein excises the damaged portion on the 5' side
  5. RRM1 protein catalyses the biosythesis of the needed repair deoxyribonucleotides from ribonucleotides
  6. The excised 22-32 nucleotide segment is then repaired by DNA polymerases associated with the accessory replication PCNA, RPA and RFC proteins
  7. DNA ligase restores the damaged strand

References

  1. ↑ Gazdar AF. DNA repair and survival in lung cancer--the two faces of Janus. The New England journal of medicine 2007;356:771-3. (Direct link – subscription may be required.)
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