Repair of short oligodeoxyribonucleotides containing a stable adduct and an apurinic site by extracts of MCF-10A1 cells.

BACKGROUND

DNA with two sites of damage in close proximity might not be repaired as efficiently as DNA with a single damage site.

MATERIALS AND

METHODS

To study this hypothesis, we utilized short oligodeoxyribonucleotides with a stable adduct 7 or 16 nucleotides (nt) downstream from an apurinic (AP) site. Repair by extracts of human breast epithelial MCF-10A1 cells was assayed by quantifying the incorporation of [alpha-32P]dTTP.

RESULTS

The level of repair of an oligodeoxyribonucleotide with an AP site 7 nt from a stable adduct was comparable to that of the oligodeoxyribonucleotide with only an AP site. A decrease in overall repair of oligodeoxyribonucleotides containing an AP site and a stable adduct was observed if these lesions were 16 nt apart compared to the presence of only an AP site.

CONCLUSION

The ability of human breast MCF-10A1 cells to repair DNA adducts and AP sites is affected by other near-by lesions.