Haugel-Nielsen, J., Hajnsdorf, E. & Régnier, P. The rpsO mRNA of Escherichia coli is polyadenylated at multiple sites resulting from endonucleolytic processing and exonucleolytic degradation. EMBO J. 15, 3144-3152

Institut de Biologie Physico-Chimique, Paris, France.
The EMBO Journal (Impact Factor: 10.43). 07/1996; 15(12):3144-52.
Source: PubMed


The rpsO monocistronic messenger, encoding ribosomal protein S15, is destabilized upon polyadenylation occurring at the hairpin structure of the transcription terminator t1. We report that mRNA fragments differing from the monocistronic transcript by their 3' termini are also polyadenylated in the absence of polynucleotide phosphorylase and RNase II. Some of these 3' extremities result from endonucleolytic cleavages by RNase E and RNase III and from exonucleolytic degradation. Most of these mRNA fragments are destabilized upon polyadenylation with the exception of the RNA species generated by RNase III. RNase E appears to reduce the amount of poly(A) added at the transcription terminator t1.

Download full-text


Available from: Eliane Hajnsdorf
  • Source
    • "RNA was isolated from bacteria lacking both PNPase and RNase II for two reasons. First, PNPase deficiency allows an accumulation of polyadenylated RNA fragments, many of which are believed to be degraded by PNPase (Braun et al., 1996; Coburn and Mackie, 1996; Haugel-Nielsen et al., 1996; Hajnsdorf and Régnier, 1999); second, inactivation of the two most active exoribonucleases of E. coli causes lengthening of poly(A) extensions that facilitates reverse transcription of RNA (Deutscher and Reuven, 1991; Hajnsdorf et al., 1995; Haugel-Nielsen et al., 1996). However, simultaneous inactivation of PNPase and RNase II may affect the composition of the poly(A) RNA sample. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Polyadenylation is a universal post-transcriptional modification involved in degradation and quality control of bacterial RNAs. In Escherichia coli, it is admitted that any accessible RNA 3' end can be tagged by a poly(A) tail for decay. However, we do not have yet an overall view of the population of polyadenylated molecules. The sampling of polyadenylated RNAs presented here demonstrates that rRNA fragments and tRNA precursors originating from the internal spacer regions of the rrn operons, in particular, rrnB are abundant poly(A) polymerase targets. Focused analysis showed that Glu tRNA precursors originating from the rrnB and rrnG transcripts exhibit long 3' trailers that are primarily removed by PNPase and to a lesser extent by RNase II and poly(A) polymerase. Moreover, 3' trimming by exoribonucleases precedes 5' end maturation by RNase P. Interestingly, characterization of RNA fragments that accumulate in a PNPase deficient strain showed that Glu tRNA precursors still harbouring the 5' leader can be degraded by a 3' to 5' quality control pathway involving poly(A) polymerase. This demonstrates that the surveillance of tRNA maturation described for a defective tRNA also applies to a wild-type tRNA.
    Full-text · Article · Dec 2011 · Molecular Microbiology
  • Source
    • "Addition of a poly(A) tract to the 39 end of RNA helps the binding of 39–59 exonucleases and promote RNA degradation. Rounds of polyadenylation and exonucleolytic digestion can overcome RNA secondary structures and complete decay (Coburn and Mackie 1996; Haugel-Nielsen et al. 1996; Régnier and Arraiano 2000). In yeast, the addition of small poly(A) stretches by the TRAMP complex targets RNA to degradation by the exosome, in close resemblance to the prokaryotic system (LaCava et al. 2005; Vanácová et al. 2005; Wyers et al. 2005). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Polyadenylation is an important factor controlling RNA degradation and RNA quality control mechanisms. In this report we demonstrate for the first time that RNase R has in vivo affinity for polyadenylated RNA and can be a key enzyme involved in poly(A) metabolism. RNase II and PNPase, two major RNA exonucleases present in Escherichia coli, could not account for all the poly(A)-dependent degradation of the rpsO mRNA. RNase II can remove the poly(A) tails but fails to degrade the mRNA as it cannot overcome the RNA termination hairpin, while PNPase plays only a modest role in this degradation. We now demonstrate that in the absence of RNase E, RNase R is the relevant factor in the poly(A)-dependent degradation of the rpsO mRNA. Moreover, we have found that the RNase R inactivation counteracts the extended degradation of this transcript observed in RNase II-deficient cells. Elongated rpsO transcripts harboring increasing poly(A) tails are specifically recognized by RNase R and strongly accumulate in the absence of this exonuclease. The 3' oligo(A) extension may stimulate the binding of RNase R, allowing the complete degradation of the mRNA, as RNase R is not susceptible to RNA secondary structures. Moreover, this regulation is shown to occur despite the presence of PNPase. Similar results were observed with the rpsT mRNA. This report shows that polyadenylation favors in vivo the RNase R-mediated pathways of RNA degradation.
    Full-text · Article · Feb 2009 · RNA
  • Source
    • "RNA fragments resulting from endonucleolytic cleavages can be either further degraded endonucleolytically or by the 3′–5′ exonucleases, polynucleotide phosphorylase (PNPase), RNase II and RNase R [reviewed in (10)]. Oligo(A) tails can be added to RNA fragments resulting from endo- or exonucleolytic cleavages and promote their exonucleolytic degradation (11). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Although usually implicated in the stabilization of mRNAs in eukaryotes, polyadenylation was initially shown to destabilize RNA in bacteria. All the data are consistent with polyadenylation being part of a quality control process targeting folded RNA fragments and non-functional RNA molecules to degradation. We report here an example in Escherichia coli, where polyadenylation directly controls the level of expression of a gene by modulating the stability of a functional transcript. Inactivation of poly(A)polymerase I causes overexpression of glucosamine-6-phosphate synthase (GlmS) and both the accumulation and stabilization of the glmS transcript. Moreover, we show that the glmS mRNA results from the processing of the glmU-glmS cotranscript by RNase E. Interestingly, the glmU-glmS cotranscript and the mRNA fragment encoding GlmU only slightly accumulated in the absence of poly(A)polymerase, suggesting that the endonucleolytically generated glmS mRNA harbouring a 5' monophosphate and a 3' stable hairpin is highly susceptible to poly(A)-dependent degradation.
    Full-text · Article · Mar 2007 · Nucleic Acids Research
Show more