title: Studies on ribosomal protein biosynthesis in an RNA polymerase temperature sensitive E. coli mutant.
abstract: In E. coli strain XH56 the synthesis of all RNA species is blocked upon shifting the culture to the non-permissive temperature. The decay of specific messenger RNA species coding for individual ribosomal (r) proteins was followed by measuring the rate of r-protein synthesis by pulse labelling at various times after the shift. The half-lives of the average 30S r-protein and 50S r-protein mRNA species are identical (1.75 min) and shorter than those of the average messenger coding for total cell proteins (2.75 min). Most individual r-protein messengers have a half-life in the same range (1.50-2.00). Only a few r-protein messengers have significantly longer half-lives: S1 (2.80 min), S17 (3.29 min), L29 (2.30 min), L31 (2.30 min), L32 (2.33 min) and L16 (2.60 min). The results indicate that the degradation of most individual r-protein mRNA species is not specifically controlled. After a few min at the non-permissive temperature, all protein synthesis is blocked. The restart of r-protein synthesis was followed after shifting the culture back to the permissive temperature. The recovery of cell growth is very slow. During this period preferential r-protein synthesis was observed. Moreover differential rates of bisynthesis of r-proteins was obtained, it may be indicative of specific regulatory process(es).
mesh_terms: D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D006207:Half-Life; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D008970:Molecular Weight; D009154:Mutation; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D012269:Ribosomal Proteins / Q000096:biosynthesis*; D013696:Temperature; D014158:Transcription, Genetic; D014529:Uridine / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D012269:Ribosomal Proteins; D012321:DNA-Directed RNA Polymerases; D007930:Leucine; D014529:Uridine