Adaptive response to mutagenesis and its molecular basis in a human T-cell leukemia line primed with a low dose of gamma-rays.
The effect was studied of a low dose of gamma-ray preexposure on the frequency and molecular spectrum of radiation-induced mutations at the hprt locus in a human T-cell leukemia line. When the cells were preexposed to 0.01 Gy of gamma-rays, the yield of mutations induced by a subsequent 2-Gy challenge dose was reduced by 60%, compared with the 2 Gy of irradiation alone. The data of Southern blot analysis showed that 47% of the mutants induced by 2 Gy in the cells without low-dose preexposure were of the deletion or rearranged mutations type. In contrast, in the low-dose radioadapted cells the proportion of this type of 2-Gy-induced mutations decreased to 28%. This is close to the control level (22%) of spontaneous mutations. Our results confirm that a low dose of gamma-ray preexposure leads to a decreased susceptibility to gene deletions and rearrangements after high-dose irradiation.
Zhou
P K
PK
Department of Biochemistry, Institute of Radiation Medicine, Beijing, P.R. China.
Xiang
X Q
XQ
Sun
W Z
WZ
Liu
X Y
XY
Zhang
Y P
YP
Wei
K
K
D004305:Dose-Response Relationship, Drug; D005720:Gamma Rays; D017353:Gene Deletion; D015321:Gene Rearrangement; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics; D015458:Leukemia, T-Cell / Q000235:genetics; D016296:Mutagenesis; D014407:Tumor Cells, Cultured
D007041:Hypoxanthine Phosphoribosyltransferase