Induced production of invertase in sugar-beet root by γ-irradiation: Role of RNA

Gamma-irradiation dosages between 100 and 200 krad greatly stimulate the development of invertase activity in sugar-beet tissue. However, exposure of tissue to 800 krad virtually eliminates the production of invertase. The production of the enzyme in control and irradiated tissue requires RNA and protein synthesis. Failure of 5-fluorouracil to inhibit the development of invertase implies that the synthesis of ribosomal RNA is not required for enzyme production. A close correlation between irradiation-stimulated methylation of sRNA and enzyme production is noted. We suggest that the synthesis or modification of some RNA required for the translation of "masked invertase RNA" is stimulated by γ-irradiation.