RNase R is a highly unstable protein regulated by growth phase and stress.

Abstract

RNase R is an important exoribonuclease that participates in the degradation of structured RNAs in Escherichia coli. In earlier work, it was shown that RNase R levels increase dramatically under certain stress conditions, particularly during cold shock and stationary phase. However, the regulatory processes that lead to this elevation are not well understood. We show here that the increase in RNase R in stationary phase is unaffected by the global regulators, RpoS and (p)ppGpp, and that it occurs despite a major reduction in rnr message. Rather, we find that RNase R is a highly unstable protein in exponential phase, with a half-life of approximately 10 min, and that the protein is stabilized in stationary phase, leading to its relative increase. RNase R is also stabilized during cold shock and by growth in minimal medium, two other conditions that lead to its elevation. These data demonstrate that RNase R is subject to regulation by a novel, posttranslational mechanism that may have important implications for our complete understanding of RNA metabolism.

• Authors: Chenglu Chen, Murray P Deutscher
• Journal: RNA (New York, N.Y.) (RNA) Vol. 16 Issue 4 Pg. 667-72 (Apr 2010) ISSN: 1469-9001 [Electronic] United States
• PMID: 20185542 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Bacterial Proteins
• Escherichia coli Proteins
• RNA, Bacterial
• Sigma Factor
• rnr protein, E coli
• sigma factor KatF protein, Bacteria
• Exoribonucleases

Topics

• Bacterial Proteins (genetics, metabolism)
• Cold Temperature
• Escherichia coli (enzymology, growth & development)
• Escherichia coli Proteins (genetics, metabolism)
• Exoribonucleases (genetics, metabolism)
• Gene Expression Regulation, Bacterial
• Protein Stability
• RNA, Bacterial (metabolism)
• Sigma Factor (genetics, metabolism)