Role of translation of the pheA leader peptide coding region in attenuation regulation of the Escherichia coli pheA gene.
In Escherichia coli, the expression of the pheA gene is regulated by attenuation of transcription. To study the molecular details of pheA attenuation, we introduced mutations in the pheA leader peptide coding region and analyzed their effects by using pheA promoter-lacZ gene transcription fusions (pheAp-lacZ). Mutations in the ribosome-binding site (pheAe1213) or in the translation initiation codon (pheAe24) of the pheA leader peptide coding region resulted in superattenuation of pheA expression. However, the presence of a stop codon upstream to the tandem phenylalanine codons (pheAe3334) led to an increase in the basal-level expression of pheA. This increase was further enhanced in the presence of prfA release factor mutant. The level of pheA expression in all three mutants was the same when cells were starved for phenylalanine. These results demonstrate that efficient translation of the pheA leader peptide coding region and the position of the ribosome on the leader transcript play decisive roles in the attenuation regulation of pheA.
Gavini
N
N
Russell Grimwade School of Biochemistry, University of Melbourne, Parkville, Victoria, Australia.
Pulakat
L
L
D001483:Base Sequence; D001665:Binding Sites; D003062:Codon; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D011302:Prephenate Dehydratase / Q000235:genetics*; D014176:Protein Biosynthesis; D021382:Protein Sorting Signals / Q000235:genetics / Q000502:physiology*; D012091:Repetitive Sequences, Nucleic Acid; D012270:Ribosomes / Q000378:metabolism
D003062:Codon; D021382:Protein Sorting Signals; D011302:Prephenate Dehydratase