Translational autocontrol of the Escherichia coli ribosomal protein S15.
When rpsO, the gene encoding the ribosomal protein S15 in Escherichia coli, is carried by a multicopy plasmid, the mRNA synthesis rate of S15 increases with the gene dosage but the rate of synthesis of S15 does not rise. A translational fusion between S15 and beta-galactosidase was introduced on the chromosome in a delta lac strain and the expression of beta-galactosidase studied under different conditions. The presence of S15 in trans represses the beta-galactosidase level five- to sixfold, while the synthesis rate of the S15-beta-galactosidase mRNA decreases by only 30 to 50%. These data indicate that S15 is subject to autogenous translational control. Derepressed mutants were isolated and sequenced. All the point mutations map in the second codon of S15, suggesting a location for the operator site that is very near to the translation initiation codon. However, the creation of deletion mutations shows that the operator extends into the 5' non-coding part of the message, thus overlapping the ribosome loading site.
Institut de Biologie Physico-Chimique, Paris, France.
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Portier
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Dondon
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Grunberg-Manago
D001482:Base Composition; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D015345:Oligonucleotide Probes; D010957:Plasmids; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D015183:Restriction Mapping; D012269:Ribosomal Proteins / Q000235:genetics*; D014158:Transcription, Genetic
D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D012269:Ribosomal Proteins; C036004:ribosomal protein S15