Ribosome structure, maturation of ribosomal RNA and drug sensitivity in temperature-sensitive mutants of Saccharomyces cerevisiae.

Selected strains of Saccharomyces cerevisiae were mutagenized with nitrosoguanidine and temperature-sensitive mutants isolated. These mutants were screened by two-dimensional gel-electrophoresis for the presence of ribosomal proteins with altered mobility relative to parental preparations. Electrophoretic changes were detected in three mutants designated ts205, ts212 and ts417, with the alterations apparently the same in the three cases. All three mutants were more sensitive than were their parents to the antibiotics G418, hygromycin B and MDMP. Mutant ts212 has an abnormal distribution of native ribosomal subunits and appears to be defective in its assembly of the smaller subparticle.