X-ray induced DNA double strand break production and repair in mammalian cells as measured by neutral filter elution.

AUTOR(ES)

Bradley, M O

RESUMO

This work presents a neutral filter elution method for detecting DNA double strand breaks in mouse L1210 cells after X-ray. The assay will detect the number of double strand breaks induced by as little as 1000 rad of X-ray. The rate of DNA elution through the filters under neutral conditions increases with X-ray dose. Certain conditions for deproteinization, pH, and filter type are shown to increase the assay's sensitivity. Hydrogen peroxide and Bleomycin also induce apparent DNA double strand breaks, although the ratios of double to single strand breaks vary from those produced by X-ray. The introduction of double strand cuts by HpA I restriction endonuclease in DNA lysed on filters results in a rapid rate of elution under neutral conditions, implying that the method can detect double strand breaks if they exist in the DNA. The eluted DNA bands with a double stranded DNA marker in cesium chloride. This evidence suggests that the assay detects DNA double strand breaks. L1210 cells are shown to rejoin most of the DNA double strand breaks induced by 5-10 krad of X-ray with a half-time of about 40 minutes.

Documentos Relacionados

• Evidence for a lack of DNA double-strand break repair in human cells exposed to very low x-ray doses
• Lack of interference of DNA single-strand breaks with the measurement of double-strand breaks in mammalian cells using the neutral filter elution assay.
• Drug-induced DNA repair: X-ray structure of a DNA-ditercalinium complex.
• Gene Conversion Tracts from Double-Strand Break Repair in Mammalian Cells
• Homology-directed repair is a major double-strand break repair pathway in mammalian cells