Nucleotide excision repair.

1. Damaged DNA is recognized by uvr (ultraviolet repair) proteins.
   
   
   
   
2. A number of nucleotides is clipped out around the lesion by a nuclease.
   
   
   
   
3. The gap is filled by DNA polymerase I and DNA ligase
   
   
   
   
4. The error is corrected.