Overcoming Dimer Damage

Science  12 Feb 1999:
Vol. 283, Issue 5404, pp. 901o
DOI: 10.1126/science.283.5404.901o

Thymine-thymine dimers are mutagenic lesions in DNA that are induced by ultraviolet radiation. Upon encountering these lesions in a DNA template, most DNA polymerases stop replicating. Johnson et al. (p. 1001) have discovered a new DNA polymerase in yeast, encoded by the RAD30 gene, that copies past these lesions at remarkable efficiency, apparently by inserting the correct nucleotides (adenines) opposite the dimers. This enzyme, DNA polymerase ε, represents another potential mechanism by which cells can protect themselves from environmentally induced DNA damage.

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