Complex regulation of the global regulatory gene csrA: CsrA-mediated translational repression, transcription from five promoters by Eσ70 and EσS, and indirect transcriptional activation by CsrA

Helen Yakhnin, Alexander V. Yakhnin, Carol S. Baker, Elena Sineva, Igor Berezin, Tony Romeo, Paul Babitzke

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

CsrA of Escherichia coli is an RNA-binding protein that globally regulates gene expression by repressing translation and/or altering the stability of target transcripts. Here we explored mechanisms that control csrA expression. Four CsrA binding sites were predicted upstream of the csrA initiation codon, one of which overlapped its Shine-Dalgarno sequence. Results from gel shift, footprint, toeprint and in vitro translation experiments indicate that CsrA binds to these four sites and represses its own translation by directly competing with 30S ribosomal subunit binding. Experiments were also performed to examine transcription of csrA. Primer extension, in vitro transcription and in vivo expression studies identified two σ70-dependent (P2 and P5) and two σS-dependent (P1 and P3) promoters that drive transcription of csrA. Additional primer extension studies identified a fifth csrA promoter (P4). Transcription from P3, which is indirectly activated by CsrA, is primarily responsible for increased csrA expression as cells transition from exponential to stationary-phase growth. Taken together, our results indicate that regulation of csrA expression occurs by a variety of mechanisms, including transcription from multiple promoters by two sigma factors, indirect activation of its own transcription, as well as direct repression of its own translation.

Original languageEnglish (US)
Pages (from-to)689-704
Number of pages16
JournalMolecular Microbiology
Volume81
Issue number3
DOIs
StatePublished - Aug 2011

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Molecular Biology

Fingerprint Dive into the research topics of 'Complex regulation of the global regulatory gene csrA: CsrA-mediated translational repression, transcription from five promoters by Eσ<sup>70</sup> and Eσ<sup>S</sup>, and indirect transcriptional activation by CsrA'. Together they form a unique fingerprint.

Cite this