Abstract
The radiosensitive mutant LX830, a derivative of the mouse leukemia L5178Y cell, is defective in DNA double-strand break rejoining ability. This cell line belongs to the XRCC4 deficiency group. LX830 cells were hypersensitive to cell killing and mutation induction by gamma rays compared to the parental cells. No dose-rate dependence was found for mutation induction in this cell line. To characterize the structural alterations at the Hprt locus in LX830 cells, we have developed the primer sets for multiplex PCR analysis of the gene. The cells were employed after the removal of pre-existing 6-thioguanine resistant (TGr) mutants by THMG (Thymidine-Hypoxanthine-Methotrexate-Glycine) treatment. Independent TGr mutant clones were isolated from unirradiated and gamma-irradiated cultures of both LX830 and L5178Y cells. The proportion of mutants with deletions, together with the size and distribution of deletions are determined by the multiplex PCR method. How the deficiency of XRCC4 protein affects the molecular nature of TGr mutants will be discussed. [J Radiat Res 44:391 (2003)]
