mRNA Stability

Udo Bläsi, University of Vienna, Vienna, Austria
Alexander von Gabain, University of Vienna, Vienna, Austria

Published online: September 2009

DOI: 10.1002/9780470015902.a0000533.pub2

The steady-state level of a messenger ribonucleic acid (mRNA) is determined by both its rate of synthesis and degradation. The degradation of mRNA is an important tool employed by cells to control gene expression, and to adjust the level of protein synthesis in response to physiological needs. The degradation of mRNA in all organisms is mastered by a rather restricted number of endo- and exoribonucleases. Some of these enzymes are phylogenetically conserved across the three domains of life – bacteria, archaea and eukarya. This review provides a brief overview on the major factors and mechanisms involved in bacterial and eukaryal mRNA degradation.

Key concepts:

  • Enzymes and factors involved in mRNA decay in prokaryotes and eukaryotes.
  • Mechanisms of mRNA decay in pro- and eukaryotes.
  • Defective mRNAs and decay.
  • Noncoding RNAs and mRNA decay.

Keywords: mRNA decay; noncoding RNAs; RNases; RNA-binding proteins

Figure 1. General mRNA decay pathways in Bacteria. (a) 3¢ to 5¢ directional pathway of bacterial mRNA decay by exoribonucleases. Upon addition of the poly(A) tail by PAP1, PNPase or RNase R can degrade the mRNA. (b) In E. coli mRNA decay can be initiated by pyrophosphate removal, followed by endonucleolytic cleavage of the 5¢-monophosphate dependent RNase E. The resulting 5¢-fragment is then degraded by 3¢ to 5¢ exonucleases like oligoribonuclease (short stretches) PNPase, RNase R or RNase II. Upon the first RNase E cleavage the downstream fragment is endowed with a 5¢-monophosphate, which serves as a signal for the next endonucleolytic cut by RNase E. Repeated cycles of RNase E-dependent endonucleolytic cleavages and exoribonucleolytic decay finally lead to 5¢ to 3¢ directional decay of the mRNA. The 3¢ end of the mRNA containing a stem–loop structure might be first polyadenylated by poly(A) polymerase I (PAPI), and then exonucleolytically degraded. (c) In B. subtilis mRNA decay can be initiated by endonucleolytic cleavage in the 5¢-part of the mRNA by RNase J1/J2. This generates a 5¢-monophosphate, which serves as a signal for the 5¢ to 3¢ exoribonuclease activity of RNase J1/J2 by which the RNA can be degraded in 5¢ to 3¢ direction.
Figure 2. Principal mRNA decay pathways in Eukaryotes. Following enzymatic removal of the 3¢-poly(A) tail, for example, by PAN in yeast, the mRNA can be degraded by two mechanisms. (1) The exosome can degrade the mRNA in 3¢ to 5¢ direction and the remaining cap structure is the enzymatically hydrolysed by the scavenger-decapping enzyme DcpS (right). (2) Deadenylation can also lead to assembly of the Lsm1-7 protein complex at the 3¢-end of the transcript and to induction of decapping by the dimeric DCP. Upon decapping the mRNA can be degraded in 5¢ to 3¢ direction by an exoribonuclease, for example, XRN1 (left).
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 Further Reading
    Condon C (2007) Maturation and degradation of RNA in bacteria. Current Opinion in Microbiology 10: 271–278.
    Garneau NL, Wilusz J and Wilusz CJ (2007) The highways and byways of mRNA decay. Molecular Cell Biology 8: 113–126.
    Kaberdin V and Bläsi U (2006) Translation initiation and the fate of bacterial mRNAs. FEMS Microbiology Reviews 30: 967–979.
    Richards J, Sundemeier T, Svetlanov A and Karzai AW (2008) Quality control of bacterial mRNA decoding and decay. Biochimica and Biophysica Acta 1779: 574–582.
    Valencia-Sanchez MA, Liu J, Hannon GJ and Parker R (2006) Control of translation and mRNA degradation by miRNAs and siRNAs. Genes and Development 20: 515–524.

Related Sub-Topics:

RNA Structure and Function | Biomolecular Interactions | Enzymes: Structure and Action Mechanism | Nucleic Acids: Structure, Function, Metabolism
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Article Title: mRNA Stability
 
How to Cite close
Bläsi, Udo, and von Gabain, Alexander(Sep 2009) mRNA Stability. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0000533.pub2]