Frequency of CD59 mutations induced in human-hamster hybrid AL cells by low-dose X-irradiation

Autor: Erhard Severin, Burkhard Greve, U. Hacker-Klom, Niels Wedemeyer, Wolfgang Köhnlein, Wolfgang Göhde, Daniela Uthe, Dagmar Denklau, Thomas Pötter
Rok vydání: 2001
Předmět:
Zdroj: Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis. 473:73-84
ISSN: 0027-5107
DOI: 10.1016/s0027-5107(00)00137-8
Popis: Determination of the genotoxic effects of ionizing radiation, especially at low-doses, is of great importance for risk assessment, e.g. in radiological diagnostics. The human-hamster hybrid A L cell line has been shown previously to be a well-suited in vitro model for the study of mutations induced by various mutagens. The A L cells contain a standard set of hamster chromosomes and a single human chromosome 11, which confers the expression of the human cell surface protein CD59. Using CD59 specific antibodies, cells mutated in the CD59 gene can be detected and quantified by the loss of the cell surface marker. In contrast to previous studies, prior to irradiation we removed spontaneous mutants by magnetic cell separation (MACS) which allows analysis of radiation-induced mutation events only. We exposed A L cells to 100 kV X-rays at 0.1 to 5 Gy. The proportions of X-irradiation-induced CD59 − mutants were quantified by flow cytometry after immunofluorescence labeling. Between 0.2 and 5 Gy the yield of CD59 mutants was a linear function of dose. The molecular analysis of individual CD59-negative clones induced after exposure of 1, 3 and 5 Gy of X-ray revealed a dose-dependent linear increase of large deletions (>6 Mbp), whereas, point mutations could be seen only in spontaneous CD59 mutants or after low-dose exposure (≤1 Gy). We conclude that the modified A L assay presented here is appropriate for detection and quantification of non-lethal DNA lesions induced by low-dose ionizing radiation.
Databáze: OpenAIRE