Postirradiation Protein Synthesis and the Inductions of Cytoplasmic and Genic Mutations in Saccharomyces by Ultraviolet Radiation

抄録

A study was made of the effects of postirradiation protein synthesis upon u.v. inductions of cytoplasmically inherited respiratory deficiency and genic reversions from adenine auxotrophy to prototrophy in Saccharomyces. Conditions affecting protein synthesis were modified by (a) varying the nutritional status of cells before and after irrradiation and by (b) use of the phenylalanine analogue, p-fluorophenylalanine. Circumstances favoring protein synthesis during the first half of the first postirradiation cell division were found essential for the induction of a maximal number of genic mutants. Previous investigators have reported similar findings with bacteria and Neurospora. Postirradiation protein synthesis did not affect the frequency with which cytoplasmic mutants were induced. These results provide additional support for the proposition that u.v. induced gene mutation is an indirect process requiring the translation of primary radiation damage into the genetic apparatus through processes involving protein synthesis. They also suggest that cytoplasmically inherited respiratory deficiency may be induced by a direct derangement by u.v. of the structural integrity of the mitochondrion.