Regulatory Interactions of Csr Components: the RNA Binding Protein CsrA Activates csrB Transcription in Escherichia coli

Salmonella biofilms: An overview on occurrence, structure, regulation and eradication

“…Both sRNAs are part of the Salmonella Csr system and antagonize the activity of the RNA-binding protein CsrA. In E. coli, CsrA indirectly activates the transcription of its RNA antagonists csrB and csrC via BarA/SirA (Gudapaty, Suzuki, Wang, Babitzke, & Romeo, 2001;Suzuki et al, 2002). It has been suggested that a similar feed-back loop exists in S. Typhimurium (Jonas et al, 2010).…”

Post-transcriptional global regulation by CsrA in bacteria

“…Furthermore, expression of CsrB and CsrC is upregulated in a UvrY-dependent manner at the onset of the stationary phase [64,65,126,131]. This overproduction leads to sequestration of CsrA, favouring glycogenesis.…”

“…Interestingly, in S. typhimurium as well as in E. coli, CsrA negatively regulates expression of the csrD homologue (STM3375) [60,125]. Although it has been shown that the E. carotovora CsrB is stabilized in presence of CsrA [102], the E. coli CsrB decay is not affected by CsrA [126].…”

“…By analysing csrB expression in Csr mutants and by complementation tests, it has been shown that CsrA regulates csrB transcription via UvrY and independently of it (Fig. 4) [64,126,127].…”

Bacterial Small RNA Regulators

“…Thus, it follows that regulation of CsrB/C synthesis and/or stability could be important regulatory checkpoints that dictate the expression of CsrA-regulated genes. Primer extension analysis to define the 5 end of the CsrB RNA showed that the promoter of the csrB gene shows significant similarity to σ 70 -like promoters (Gudapaty et al, 2001). Northern blot analysis of CsrB levels throughout the growth curve showed that CsrB RNA levels rise modestly (three-fold) as wild-type cells enter stationary phase.…”