Poly(A)-polymerase I links transcription with mRNA degradation via sigmaS proteolysis.
Bacteria rapidly adapt to changes in growth conditions through control of transcription and specific mRNA degradation. Interplay of both mechanisms must exist in order to achieve fine-tuned regulation of gene expression. Transcription of the Escherichia coli bolA gene is mediated by the RpoS/sigmaS transcription factor in response to environmental signals. In this report it is shown that the mechanisms of bolA1p mRNA transcription and degradation are tightly connected at the onset of stationary phase and in response to sudden carbon starvation. In stationary phase, bolA1p mRNA levels were reduced 2.5-fold in a poly(A)-polymerase I (PAPI) mutant, explained by the significant threefold reduction in sigmaS protein levels in the same strain. Furthermore, fusions with the rpoS gene, analysis of the stability of sigmaS and the levels of RssB indicate that the absence of PAPI enhances RssB-mediated sigmaS proteolysis specifically in starved cells. The fact that PAPI induces higher cellular levels of a global regulator is a novel finding of wide biological significance. PAPI could work as a linker between transcription and mRNA degradation with the ultimate goal of adapting and surviving to growth-limiting conditions.
Instituto de Tecnologia Química e Biológica (ITQB), Universidade Nova de Lisboa, Apt 127, 2781-901 Oeiras, Portugal.
Jorge M
JM
Santos
Patrick
P
Freire
Francisco S
FS
Mesquita
Franziska
F
Mika
Regine
R
Hengge
Cecília M
CM
Arraiano
D001426:Bacterial Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D011062:Polynucleotide Adenylyltransferase / Q000235:genetics / Q000378:metabolism*; D020871:RNA Stability; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D012808:Sigma Factor / Q000378:metabolism*; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D012333:RNA, Messenger; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; D011062:Polynucleotide Adenylyltransferase; C063643:pcnB protein, E coli