A dedicated translation factor controls the synthesis of the global regulator Fis

• Autores: Róisín M. Owens, Gareth Pritchard, Sean R. Connell, Knud H. Nierhaus
• Localización: EMBO journal: European Molecular Biology Organization, ISSN 0261-4189, Nº. 16, 2004, págs. 3375-3385
• Idioma: inglés
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• Resumen

  • BipA is a highly conserved protein with global regulatory properties in Escherichia coli. We show here that it functions as a translation factor that is required specifically for the expression of the transcriptional modulator Fis. BipA binds to ribosomes at a site that coincides with that of elongation factor G and has a GTPase activity that is sensitive to high GDP:GTP ratios and stimulated by 70S ribosomes programmed with mRNA and aminoacylated tRNAs. The growth rate-dependent induction of BipA allows the efficient expression of Fis, thereby modulating a range of downstream processes, including DNA metabolism and type III secretion. We propose a model in which BipA destabilizes unusually strong interactions between the 5′ untranslated region of fis mRNA and the ribosome. Since BipA spans phylogenetic domains, transcript-selective translational control for the ‘fast-track’ expression of specific mRNAs may have wider significance.