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Modulation of the nucleoid, the transcription apparatus, and the translation machinery in bacteria for stationary phase survival
Author(s) -
Ishihama Akira
Publication year - 1999
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1046/j.1365-2443.1999.00247.x
Subject(s) - nucleoid , biology , ribosome , transcription (linguistics) , microbiology and biotechnology , stationary phase , transcription factor , bacterial transcription , sigma factor , exponential growth , dna binding protein , protein subunit , escherichia coli , gene , genetics , rna , rna polymerase , chemistry , physics , linguistics , philosophy , chromatography , quantum mechanics
Upon sensing an impending saturation level of their population density, Escherichia coli cells enter into the stationary phase. We have identified structural and functional modulations of the nucleoid, the transcription apparatus and the translation machinery occurring during the transition from exponential growth to stationary phase. The major DNA‐binding proteins, Fis, HU and Hfq, in the exponential‐phase nucleoid are replaced by a single stationary‐phase protein Dps, thereby compacting the nucleoid and ultimately leading to silencing of the DNA functions. The transcription apparatus is modified by replacing the major promoter recognition subunit, σ 70 , with σ S . A stationary‐phase protein, Rsd (Regulator of Sigma D), with the binding activity of σ 70 is involved in the efficient replacement of σ and/or the storage of unused σ 70 . Changes in cytoplasmic composition also differentially influence the activity of Eσ 70 and Eσ S holoenzymes. Together, these effects may result in the preferential transcription of stationary‐phase specific genes. The translation machinery is also modulated in stationary phase, by the formation of translationally incompetent 100S ribosomes. A small stationary‐phase protein, RMF (Ribosome Modulation Factor), is involved in the dimerization of 70S ribosome monomers.