A low, adaptive dose of gamma-rays reduced the number and altered the spectrum of S1- mutants in human-hamster hybrid AL cells.
We examined the effects of a low, adaptive dose of 137Cs-gamma-irradiation (0.04 Gy) on the number and kinds of mutants induced in AL human-hamster hybrid cells by a later challenge dose of 4 Gy. The yield of S1- mutants was significantly less (by 53%) after exposure to both the adaptive and challenge doses compared to the challenge dose alone. The yield of hprt- mutants was similarly decreased. Incubation with cycloheximide (CX) or 3-aminobenzamide largely negated the decrease in mutant yield. The adaptive dose did not perturb the cell cycle, was not cytotoxic, and did not of itself increase the mutant yield above background. The adaptive dose did, however, alter the spectrum of S1- mutants from populations exposed only to the adaptive dose, as well as affecting the spectrum of S1- mutants generated by the challenge dose. The major change in both cases was a significant increase in the proportion of complex mutations compared to small mutations and simple deletions.
Ueno
A M
AM
Department of Radiological Health Sciences, Colorado State University, Fort Collins 80523, USA.
Vannais
D B
DB
Gustafson
D L
DL
Wong
J C
JC
Waldren
C A
CA
D000222:Adaptation, Physiological / Q000235:genetics / Q000528:radiation effects*; D000818:Animals; D000954:Antigens, Surface / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D001549:Benzamides / Q000494:pharmacology; D015139:Blotting, Southern; D016923:Cell Death / Q000187:drug effects / Q000528:radiation effects; D002880:Chromosomes, Human, Pair 11 / Q000528:radiation effects; D006224:Cricetinae; D003513:Cycloheximide / Q000494:pharmacology; D004307:Dose-Response Relationship, Radiation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005720:Gamma Rays; D006801:Humans; D006822:Hybrid Cells / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics / Q000528:radiation effects; D009154:Mutation; D016133:Polymerase Chain Reaction; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology
D000954:Antigens, Surface; D001549:Benzamides; D004791:Enzyme Inhibitors; D011838:Radiation-Sensitizing Agents; C025160:3-aminobenzamide; D003513:Cycloheximide; D007041:Hypoxanthine Phosphoribosyltransferase