Differential effect of ionizing radiation on transcription in repair-deficient and repair-proficient mice.
Experiments were designed to examine in vivo changes in total transcription and in the expression of the c-fos gene following whole-body exposure of mice to JANUS fission-spectrum neutrons. Radiation repair-deficient (wst/wst) and -proficient (wst/., C57BL/6 x C3H F1) mice were exposed to JANUS fission-spectrum neutrons calibrated to deliver a gut dose of 50 cGy. Animals were sacrificed less than 10 or at 60 min postirradiation, and gut tissues were removed for study. Our results revealed that, in repair-proficient mice, an immediate depression (relative to untreated control) in total transcription was evident that continued through 1 h postirradiation. Conversely, radiation-sensitive wst/wst mice displayed doubled transcription levels postirradiation. Expression of c-fos was consistently depressed following radiation exposure in control and wst/wst mice. However, the depression of c-fos mRNA was delayed in wst/wst mice relative to controls. These results demonstrate abnormal regulation of transcription and of c-fos mRNA accumulation in repair-deficient wasted mice following exposure to ionizing radiation. In addition, this work documents rapid total transcriptional depression in normal mice following radiation exposure.
Biological and Medical Research Division, Argonne National Laboratory, Illinois 60439.
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Munson
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Woloschak
D000818:Animals; D002467:Cell Nucleus / Q000528:radiation effects; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D004260:DNA Repair; D006579:Heterozygote; D007422:Intestines / Q000528:radiation effects; D051379:Mice; D008815:Mice, Inbred Strains; D008817:Mice, Mutant Strains; D009502:Neutrons; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016760:Proto-Oncogene Proteins c-fos; D011519:Proto-Oncogenes / Q000528:radiation effects*; D012313:RNA / Q000235:genetics / Q000302:isolation & purification / Q000528:radiation effects; D014158:Transcription, Genetic / Q000528:radiation effects*; D014916:Whole-Body Irradiation
D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D012313:RNA; D011505:Protein-Tyrosine Kinases