title: Effect of whole-body irradiation on transcription in the rat thymus.
abstract: Studies were carried out to elucidate the mechanism underlying the impairment in RNA synthesis in the rat thymus after whole-body exposure to X-rays (1000 rad). The ability of thymus nuclei to catalyse RNA polymerization in vitro was adversely affected in irradiated rats. Further experiments showed that whole-body irradiation caused a considerable decrease in both the activity of RNA polymerase and the template efficiency of chromatin but not in that of DNA isolated from chromatin. These radiation-induced changes in transcription seem to arise partly from the direct effect of radiation on the thymus itself and partly from the abscopal mechanism(s).
mesh_terms: D000818:Animals; D002250:Carbon Radioisotopes; D002843:Chromatin / Q000528:radiation effects; D004247:DNA / Q000528:radiation effects; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D008297:Male; D010761:Phosphorus Radioisotopes; D012313:RNA / Q000096:biosynthesis; D011831:Radiation Genetics; D051381:Rats; D013950:Thymus Gland / Q000201:enzymology / Q000378:metabolism / Q000528:radiation effects*; D014158:Transcription, Genetic / Q000528:radiation effects*; D014965:X-Rays
chemical_list: D002250:Carbon Radioisotopes; D002843:Chromatin; D010761:Phosphorus Radioisotopes; D012313:RNA; D004247:DNA; D012321:DNA-Directed RNA Polymerases