Radiation-induced mutation at tandem repeat DNA Loci in the mouse germline: spectra and doubling doses.
The spectra and dose response for mutations at expanded simple tandem repeat (ESTR) loci in the germline of male mice acutely exposed to low-LET X or gamma rays at pre-meiotic stages of spermatogenesis were compared in five strains of laboratory mice. Most mutation events involved the gain or loss of a relatively small number of repeat units, and the distributions of length changes were indistinguishable between the exposed and control males. Overall, a significant bias toward gains of repeats was detected, with approximately 60% of mutants showing gains. The values for ESTR mutation induction did not differ substantially between strains. The highest values of doubling dose were obtained for two genetically related strains, BALB/c and C.B17 (mean value 0.98 Gy). The estimates of doubling dose for three other strains (CBA/H, C57BL/6 x CBA/H F1 and 129SVJ x C57BL/6) were lower, with a mean value of 0.44 Gy. The dose response for ESTR mutation across all five strains was very close to that for the specific loci (Russell 7-locus test). The mechanisms of ESTR mutation induction and applications of this system for monitoring radiation-induced mutation in the mouse germline are discussed.
Dubrova
Yuri E
YE
Department of Genetics, University of Leicester, Leicester LE1 7RH, United Kingdom. yed2@le.ac.uk
D000818:Animals; D004247:DNA / Q000528:radiation effects*; D004249:DNA Damage; D004252:DNA Mutational Analysis / Q000379:methods*; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D018095:Germ-Line Mutation / Q000528:radiation effects*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D048631:Micronucleus, Germline / Q000528:radiation effects; D040641:Quantitative Trait Loci; D011829:Radiation Dosage; D020080:Tandem Repeat Sequences / Q000528:radiation effects*; D014965:X-Rays
D004247:DNA