The CbrB Regulon: Promoter dissection reveals novel insights into the CbrAB expression network in Pseudomonas putida

PLoS One. 2018 Dec 17;13(12):e0209191. doi: 10.1371/journal.pone.0209191. eCollection 2018.

Abstract

CbrAB is a high ranked global regulatory system exclusive of the Pseudomonads that responds to carbon limiting conditions. It has become necessary to define the particular regulon of CbrB and discriminate it from the downstream cascades through other regulatory components. We have performed in vivo binding analysis of CbrB in P. putida and determined that it directly controls the expression of at least 61 genes; 20% involved in regulatory functions, including the previously identified CrcZ and CrcY small regulatory RNAs. The remaining are porines or transporters (20%), metabolic enzymes (16%), activities related to protein translation (5%) and orfs of uncharacterised function (38%). Amongst the later, we have selected the operon PP2810-13 to make an exhaustive analysis of the CbrB binding sequences, together with those of crcZ and crcY. We describe the implication of three independent non-palindromic subsites with a variable spacing in three different targets; CrcZ, CrcY and operon PP2810-13 in the CbrAB activation. CbrB is a quite peculiar σN-dependent activator since it is barely dependent on phosphorylation for transcriptional activation. With the depiction of the precise contacts of CbrB with the DNA, the analysis of the multimerisation status and its dependence on other factors such as RpoN o IHF, we propose a model of transcriptional activation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Binding Sites
  • Chromatin Immunoprecipitation
  • Data Mining
  • Gene Expression Regulation, Bacterial
  • Models, Biological
  • Mutagenesis, Site-Directed
  • Promoter Regions, Genetic*
  • Protein Binding
  • Pseudomonas putida / genetics*
  • Pseudomonas putida / metabolism*
  • RNA, Bacterial / metabolism
  • Real-Time Polymerase Chain Reaction
  • Sequence Analysis, DNA
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcriptional Activation / physiology

Substances

  • Bacterial Proteins
  • RNA, Bacterial
  • Transcription Factors

Grants and funding

This work was supported by the Spanish Ministry of Economy, Industry y Competitivity, grant BIO2014-57545-R awarded to IC and ES. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.