title: Assembly of the mitochondrial ribosomes in a temperature-conditional mutant of Saccharomyces cerevisiae defective in the synthesis of the var1 protein.
abstract: An investigation of the role of the var1 protein in the assembly of the yeast mitochondrial ribosomes was carried out in a temperature conditional mutant, strain h56, which contains a mutation (tsv1) just upstream of the structural gene for the var1 protein. The mutation results in a marked decrease in the synthesis of the var1 protein at the permissive temperature of 28 degrees C and an apparently complete absence of var1 synthesis at the restrictive temperature of 36 degrees C. Long-term growth of strain h56 at the non-permissive temperature was found to result in the loss of the small (37 S) ribosomal subunit and the appearance of a novel 30 S ribonucleoparticle. Both the small (37 S) and the large (54 S) mitochondrial ribosomal subunits were found to be assembled in strain h56 for at least 3 h after transfer to the non-permissive temperature.
mesh_terms: D005656:Fungal Proteins / Q000096:biosynthesis* / Q000235:genetics; D008565:Membrane Proteins; D008661:Metabolism, Inborn Errors / Q000378:metabolism / Q000473:pathology*; D008928:Mitochondria / Q000648:ultrastructure*; D024101:Mitochondrial Proteins; D009154:Mutation; D012269:Ribosomal Proteins; D012270:Ribosomes / Q000648:ultrastructure*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013696:Temperature
chemical_list: D005656:Fungal Proteins; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; C026383:VAR1 protein, S cerevisiae