Insitu nick translation, an alternative to cytogenetics in analyzing mutagen effects on human-cells.

International journal of oncology

PubMedID: 21573640

Wang R, Hsu T, Liang J. Insitu nick translation, an alternative to cytogenetics in analyzing mutagen effects on human-cells. Int J Oncol. 1993;2(6):873-6.
A chromosomal break indicates a double-stranded DNA break of the chromatin fiber. Cytogenetic observations can enumerate chromosome breaks but cannot detect single-stranded DNA breaks (nicks). When a high frequency of chromosomal breaks occurs in a cell population, whether spontaneously occurred or mutagen induced, a higher frequency of nicks is expected. In order to correlate these two type of DNA lesions, we used human lymphoblastoid lines known to be either hypersensitive or relatively resistant to the genotoxicity of bleomycin. The frequency of nicks was estimated by grain counts over interphase nuclei in autoradiographs following the technique of in situ nick translation. Good agreement was found between these two sets of data, viz, hypersensitive lines showed a high frequency of chromatid breaks as well as a high frequency of grain counts, and vice versa. These results suggest that the phenomenon of differential bleomycin sensitivity is genetically determined.