Polyadenylation of a functional mRNA controls gene expression in Escherichia coli.
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.
Joanny
Géraldine
G
Régulation de l'Expression Génétique chez les Microorganismes, UPR CNRS no 9073, conventionnée avec l'Université Paris 7-Denis Diderot, Paris, France.
Le Derout
Jacques
J
Bréchemier-Baey
Dominique
D
Labas
Valérie
V
Vinh
Joelle
J
Régnier
Philippe
P
Hajnsdorf
Eliane
E
D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing) / Q000235:genetics* / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D026723:Polyadenylation; D011062:Polynucleotide Adenylyltransferase / Q000235:genetics; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism; D015854:Up-Regulation
D029968:Escherichia coli Proteins; C520333:GlmU protein, E coli; D009097:Multienzyme Complexes; D012333:RNA, Messenger; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing); D011062:Polynucleotide Adenylyltransferase; C063643:pcnB protein, E coli