Edeine inhibition and resistance in Neurospora

Abstract

To obtain data on the biochemical effects of edeine in the fungus Neurospora crassa, in vivo protein synthesis, in vitro protein synthesis, as well as in vivo RNA and DNA synthesis of the wildtype and an edeine resistant mutant were measured.—Incorporation of ³H leucine into conidia of both strains, which served as a measure for in vivo protein synthesis, was inhibited by 200 μg edeine/ml as follows: Wildtype approx. 40%, mutant approx. 6%.—Incorporation of ¹⁴C phenylalanine into polyphenylalanine in a cell free system with ribosomes from either the wildtype or the mutant, was inhibited between 74 and 95% by edeine at a ratio of 2 molecules edeine per ribosome.—Incorporation of ³H adenosine into conidia, serving as a measure for in vivo RNA synthesis, was inhibited in the wild-type (approx. 30% inhibition by 200 μg edeine/ml). It was, however, not influenced in the ed ^rmutant. Similarly, in vivo DNA synthesis was decreased in the wildtype, but not in the mutant.—These results suggest that edeine acts at more than one site. The resistance of the mutant ed ^r-29 (ed ^r-2 locus) is tentatively interpreted as due to a block in edeine uptake.