nucleotide excision repair

(noun)

a DNA repair mechanism that corrects damage done by UV radiation, including thymine dimers and 6,4 photoproducts that cause bulky distortions in the DNA

Related Terms

  • mismatch repair

Examples of nucleotide excision repair in the following topics:

  • DNA Repair

    • If it is the correct base, the next nucleotide is added.
    • The enzymes recognize the incorrectly-added nucleotide and excise it; this is then replaced by the correct base.
    • In another type of repair mechanism, nucleotide excision repair, enzymes replace incorrect bases by making a cut on both the 3' and 5' ends of the incorrect base .
    • Nucleotide excision repairs thymine dimers.
    • In normal cells, they are excised and replaced.
  • DNA Replication in Prokaryotes

    • The addition of nucleotides requires energy; this energy is obtained from the nucleotides that have three phosphates attached to them, similar to ATP which has three phosphate groups attached.
    • DNA pol III is the enzyme required for DNA synthesis; DNA pol I and DNA pol II are primarily required for repair.
    • It also requires a free 3'-OH group to which it can add nucleotides by forming a phosphodiester bond between the 3'-OH end and the 5' phosphate of the next nucleotide.
    • This means that it cannot add nucleotides if a free 3'-OH group is not available.
    • The replication fork moves at the rate of 1000 nucleotides per second.
  • Genome Evolution

    • Mutations can result in the addition or deletion of one or more nucleotide bases.
    • The "cut-and-paste" mechanism works by excising DNA from one place in the genome and inserting itself into another location in the code.
    • There are many mechanisms by which a functional gene can become a pseudogene including the deletion or insertion of one or multiple nucleotides.
  • Gene rearrangement within genomes

    • The DNA sequences from two individuals of the same species are highly similar, differing by only about 1 in 1,000 nucleotides.
    • In both meiotic and mitotic cells, recombination between homologous chromosomes is a common mechanism used in DNA repair.
    • Genetic recombination and recombinational DNA repair also occurs in bacteria and archaea.
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