Poly(A)‐polymerase I links transcription with mRNA degradation via σ^S proteolysis

Abstract

SummaryBacteria 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/ σ σ σ σ S 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 σ σ σ σ S protein levels in the same strain. Furthermore, fusions with the rpoS gene, analysis of the stability of σ σ σ σ S and the levels of RssB indicate that the absence of PAPI enhances RssB-mediated σ σ σ σ S 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.

Global gene expression mediated by Thermus thermophilus SdrP, a CRP/FNR family transcriptional regulator

“…in a synthetic medium or stationary growth phase, insufficient nutrients and energy might be supplied through the activity of some SdrP‐regulated gene products. It has been shown that polyadenylation of mRNA is possibly an important factor that promotes adaptation to slow growth conditions such as those under which the amount of nutrients is limited (Jasiecki and Wegrzyn, 2003; Santos et al ., 2006). Oxidative damage may occur to DNA and proteins in T. thermophilus , especially in the stationary phase, as observed in many bacteria (Bridges, 1993; Ballesteros et al ., 2001; Nyström, 2004).…”

The Response Regulator SprE (RssB) Modulates Polyadenylation and mRNA Stability inEscherichia coli

“…Santos et al (42) noted that in the absence of PAP I, RpoS levels were reduced by threefold in stationary-phase cells. They also demonstrated that the effect seen was posttranscriptional and specifically affected protein stability.…”

BolA Inhibits Cell Elongation and Regulates MreB Expression Levels

“…Total RNA was extracted as previously described. 7 Equal amounts of total RNA were blotted onto Hybond + membranes (GE) and fixed by UV light. An mreB DNA probe spanning the entire mreB orf was obtained by PCR using Taq polymerase (Roche) and the primers MreB1 (5′-attgacctgggtactgcg-3′) and MreB2 (5′-ctcttcgctgaacaggtc-5′) produced by STABVida.…”

“…4 The expression of bolA is tightly controlled. [5][6][7] bolA increases biofilm formation 8 and modulates cell permeability; 9 in addition, it was demonstrated that bolA increases the expression of PBP5, PBP6 and ampC mRNA. 10,11 In this work, we analyzed the effect of BolA on cell growth and elongation using a set of specific antibiotics that induce known morphology alterations through the inhibition of PBPs.…”