Detection of Genetic Alterations Induced by Low-Dose X Rays: Analysis of Loss of Heterozygosity for TK Mutation in Human Lymphoblastoid Cells

Abstract Morimoto, S., Kato, T., Honma, M., Hayashi, M., Hanaoka, F. and Yatagai, F. Detection of Genetic Alterations Induced by Low-Dose X Rays: Analysis of Loss of Heterozygosity for TK Mutation in Human Lymphoblastoid Cells. Radiat. Res. 157, 533–538 (2002). To elucidate the genetic influence of low-dose ionizing radiation at the chromosome level, we exposed human lymphoblastoid TK6-20C cells to 10 cGy of X rays. The TK mutation frequency was 5.7 ± 1.3 × 10−6 at the background level and 6.9 ± 2.8 × 10−6 after X irradiation. Although this small increase was not statistically significant (P = 0.40), we applied multilocus analysis using 4 TK locus markers and 12 microsatellite loci spanning chromosome 17 for TK mutants exhibiting loss of heterozygosity (LOH). The analysis demonstrated a clear effect of low-dose ionizing radiation. We observed radiation-specific patterns in the extent of hemizygous LOH in 14 TK mutants among the 92 mutants analyzed. The deleted regions in these patterns were larger than th...