Non-Repairable Strand Breaks Induced by 125I Incorporated into Mammalian DNA

AUTOR(ES)

Painter, R. B.

RESUMO

When 125I is incorporated into Chinese hamster DNA (via 125I-labeled iododeoxyuridine) and the cells are stored at 77°K, the resulting decays of the isotope cause 4 to 5 breaks/single-strand per disintegration. On the average, about 50% of these breaks are repaired. In contrast, under the same conditions of storage and in the same range of total strand breaks/cell, 70-100% of the breaks induced by x-radiation are repaired. Thus, the extreme toxicity of 125I when incorporated into DNA is correlated with the unrepaired breaks caused by decay of this isotope. These results suggest that unrepaired DNA strand breaks may be important in cell killing after treatments which damage DNA.

Documentos Relacionados

• Sequence-specific DNA double-strand breaks induced by triplex forming 125I labeled oligonucleotides.
• Site-specific strand breaks in RNA produced by 125I radiodecay
• Radioprobing of DNA: distribution of DNA breaks produced by decay of 125I incorporated into a triplex-forming oligonucleotide correlates with geometry of the triplex.
• The joining of non-complementary DNA double-strand breaks by mammalian extracts.
• Illegitimate recombination induced by DNA double-strand breaks in a mammalian chromosome.