DELETION-PATTERN ANALYSIS OF A-PARTICLE AND X-RAY-INDUCED MUTATIONS AT THE HPRT LOCUS OF V79 CHINESE-HAMSTER CELLS

To investigate the mutagenic mechanisms of low-energy a particles V79 Chinese hamster cells were irradiated with Am-241-alpha particles (mea n LET of 112 keV/mu m). Parallel experiments were performed using 300 kV X-rays. Cell inactivation and mutation induction cross sections wer e measured. At approximately 20%-survival level, DNA deletions were an alysed at the HPRT locus by multiplex-PCR-analysis of all nine exons o f 47 alpha-irradiated and 36 background mutants. 92 HPRT- mutants isol ated after 300 kV-X-irradiation were analysed similarly for comparison , along with 15 corresponding background mutants. The resulting mutant deletion-pattern distributions were corrected for background mutation s. alpha Particles induced a larger fraction of deletions than X-rays. Furthermore, non-contiguous partial deletions were present among the alpha-induced mutants, a type not found after X-irradiation. (C) 1998 Elsevier Science B.V. All rights reserved.