The oxygen effect on transcription inhibition in yeast.

No oxygen effect is found if X-ray-induced inhibition of ribosomal RNA synthesis in yeast is assessed immediately after exposure. A 20-h liquid holding period, however, leads to a differential recovery in diploid cells which is markedly greater after irradiation in nitrogen. Haploid yeast exhibits a much smaller recovery and does not show any significant difference between exposures in air or nitrogen.