Radiosensitive Down syndrome lymphoblastoid lines have normal ionizing-radiation-induced inhibition of DNA synthesis.
The extent of X-ray-induced inhibition of DNA synthesis was determined in radiosensitive lymphoblastoid lines from 3 patients with Down syndrome and 3 patients with ataxia telangiectasia (AT). Compared to 6 normal control lines, the 3 AT lines were abnormally resistant to X-ray-induced inhibition of DNA synthesis, while the 3 Down syndrome lines had normal inhibition. These results demonstrate that radiosensitive human cells can have normal X-ray-induced inhibition of DNA synthesis and provide new evidence for the dissociation of radiosensitivity from radioresistant DNA synthesis.
Ganges
M B
MB
Dermatology Branch National Cancer Institute, Bethesda, MD 20892.
Tarone
R E
RE
Jiang
H X
HX
Hauser
C
C
Robbins
J H
JH
D001260:Ataxia Telangiectasia / Q000235:genetics*; D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects; D004260:DNA Repair; D004261:DNA Replication / Q000187:drug effects*; D004307:Dose-Response Relationship, Radiation; D004314:Down Syndrome / Q000235:genetics*; D006801:Humans; D014965:X-Rays