Characterization of blasticidin S-resistant mutants of Saccharomyces cerevisiae.

Blasticidin S-resistant mutants of S. cerevisiae were isolated and characterized. Resistant mutations were found to fall into two complementation groups. A single recessive nuclear gene was responsible for each group, donated as bls1 and bls2, respectively. A gene bls1 was linked to an ilv3 gene located on the right arm of chromosome X. The resistant phenotypes from both genes were not associated with ribosomes known to be target sites of Blasticidin S, when analyzed by poly(U)-directed polyphenylalanine synthesis. The resistant mechanisms of the mutations are discussed in this paper.