Cryptopleurine resistance: genetic locus for a 40S ribosomal component in Saccharomyces cerevisiae

Mutants resistant to the phenanthrene alkaloids tylophorine, tylocrebrine, and cryptopleurine have been isolated from the yeast Saccharomyces cerevisiae. A single recessive nuclear gene was responsible for resistance. This resistance locus, cry, was closely linked to the mating locus (2.2 centimorgans). The resistance was ribosomal and was due to an altered 40S ribosomal subunit. The mode of action of these drugs has been examined, and they appear to inhibit the translocation phase of protein synthesis.