title: Ribosome Shut-Down by 16S rRNA Fragmentation in Stationary-Phase Escherichia coli.
abstract: Stationary-phase bacterial cells are characterized by vastly reduced metabolic activities yielding a dormant-like phenotype. Several hibernation programs ensure the establishment and maintenance of this resting growth state. Some of the stationary phase-specific modulations affect the ribosome and its translational activity directly. In stationary-phase Escherichia coli, we observed the appearance of a 16S rRNA fragmentation event at the tip of helix 6 within the small ribosomal subunit (30S). Stationary-phase 30S subunits showed markedly reduced activities in protein biosynthesis. On the other hand, the functional performance of stationary-phase large ribosomal subunits (50S) was indistinguishable from particles isolated from exponentially growing cells. Introduction of the 16S rRNA cut in vitro at helix 6 of exponential phase 30S subunits renders them less efficient in protein biosynthesis. This indicates that the helix 6 fragmentation is necessary and sufficient to attenuate translational activities of 30S ribosomal subunits. These results suggest that stationary phase-specific cleavage of 16S rRNA within the 30S subunit is an efficient means to reduce global translation activities under non-proliferating growth conditions.
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
authors.forename: Hannes
authors.initials: H
authors.lastname: Luidalepp
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Berger
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Joss
authors.affiliation: Institute of Technology, University of Tartu, Nooruse 1, 50411 Tartu, Estonia.
authors.forename: Tanel
authors.initials: T
authors.lastname: Tenson
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland. Electronic address: norbert.polacek@dcb.unibe.ch.
authors.forename: Norbert
authors.initials: N
authors.lastname: Polacek
mesh_terms: D004926:Escherichia coli / Q000235:genetics*; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012269:Ribosomal Proteins / Q000235:genetics; D054657:Ribosome Subunits / Q000235:genetics*
chemical_list: D012336:RNA, Ribosomal, 16S; D012269:Ribosomal Proteins
keywords: 16S rRNA; 30S ribosomal subunits; RNA cleavage; stationary-phase bacteria; translation