Effects of X-irradiation on the hybridization of rat thymus nuclear RNA with repeated and unique DNA sequences.

ABSTRACT

The kinetics of DNA hybridization with heterogeneous nuclear RNA (hnRNA) from normal and phytohaemagglutinin (PHA)-stimulated thymocytes has been studied in control rats and in animals 30 min after exposure to whole-body X-radiation with 400 rad. Irradiation results in a diminished ability of hnRNA to form hybrids with DNA at all C0t values ranging from 10(-3) to 10(4). Since this effect is most pronounced in the regions of low repetitive and unique DNA sequences, it is concluded that whole-body X-irradiation of animals may also suppress the transcription, particularly, in these regions.