Gene expression changes in mouse brain after exposure to low-dose ionizing radiation.
OBJECTIVE
To characterize the cellular functions associated with the altered transcript profiles of mouse brain exposed to low-dose in vivo gamma-irradiation.


METHODS
Cerebral RNA was isolated at 30 min and 4 h after whole-body irradiation at 0.1 or 2 Gy, hybridized to random oligonucleotide arrays, and evaluated for time and dose-response patterns by multifactorial analyses.


RESULTS
Brain irradiation modulated the expression patterns of 1574 genes, of which 855 showed more than 1.5-fold variation. about 30% of genes showed dose-dependent variations, including genes exclusively affected by 0.1 Gy. About 60% of genes showed time-dependent variation with more genes affected at 30 min than at 4 h. Early changes involved signal transduction, ion regulation and synaptic signalling. Later changes involved metabolic functions including myelin and protein synthesis. Low-dose radiation also modulated the expression of genes involved in stress response, cell-cycle control and DNA synthesis/repair.


CONCLUSIONS
Doses of 0.1 Gy induced changes in gene expression that were qualitatively different from those at 2 Gy. The findings suggest that low-dose irradiation of the brain induces the expression of genes involved in protective and reparative functions, while down-modulating genes involved in neural signalling activity.
Yin
E
E
Biology and Biotechnology Research Program Lawrence Livermore National Laboratory Livermore CA 94 550 USA.
Nelson
D O
DO
Coleman
M A
MA
Peterson
L E
LE
Wyrobek
A J
AJ
D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D005786:Gene Expression Regulation / Q000528:radiation effects*; D016678:Genome; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D012313:RNA / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects*; D011829:Radiation Dosage; D011839:Radiation, Ionizing; D017423:Sequence Analysis, RNA / Q000379:methods*; D014158:Transcription, Genetic / Q000528:radiation effects*
D012313:RNA