Deficient repair of chemical adducts in α DNA of monkey cells

Miriam E. Zolan, Gino A Cortopassi, Charles Allen Smith, Philip C. Hanawalt

Research output: Contribution to journalArticlepeer-review

78 Scopus citations


We have examined excision repair of DNA damage in the highly repeated α DNA sequence of cultured African green monkey cells. Irradiation of cells with 254 nm ultraviolet light resulted in the same frequency of pyrimidine dimers in α DNA and the bulk of the DNA. The rate and extent of pyrimidine dimer removal, as judged by measurement of repair synthesis, was also similar for α DNA and bulk DNA. In cells treated with furocoumarins and long-wavelength ultraviolet light, however, repair synthesis in α DNA was only 30% of that in bulk DNA, although it followed the same time course. We found that this reduced repair was not caused by different initial amounts of furocoumarin damage or by different sizes of repair patches, as we found these to be similar in the two DNA species. Direct quantification demonstrated that fewer furocoumarin adducts were removed from α DNA than from bulk DNA. In cells treated with another chemical DNA-damaging agent, N-acetoxy-2-acetylaminofluorene, repair synthesis in α DNA was 60% of that in bulk DNA. These results show that the repair of different kinds of DNA damage can be affected to different extents by some property of this tandemly repeated heterochromatic DNA. To our knowledge, this is the first demonstration in primate cells of differential repair of cellular DNA sequences.

Original languageEnglish (US)
Pages (from-to)613-619
Number of pages7
Issue number3
StatePublished - 1982
Externally publishedYes

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Medicine(all)


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