Interplay between the catabolite repression control protein Crc, Hfq and RNA in Hfq-dependent translational regulation in Pseudomonas aeruginosa

Nucleic Acids Res. 2018 Feb 16;46(3):1470-1485. doi: 10.1093/nar/gkx1245.


In Pseudomonas aeruginosa the RNA chaperone Hfq and the catabolite repression control protein (Crc) act as post-transcriptional regulators during carbon catabolite repression (CCR). In this regard Crc is required for full-fledged Hfq-mediated translational repression of catabolic genes. RNAseq based transcriptome analyses revealed a significant overlap between the Crc and Hfq regulons, which in conjunction with genetic data supported a concerted action of both proteins. Biochemical and biophysical approaches further suggest that Crc and Hfq form an assembly in the presence of RNAs containing A-rich motifs, and that Crc interacts with both, Hfq and RNA. Through these interactions, Crc enhances the stability of Hfq/Crc/RNA complexes, which can explain its facilitating role in Hfq-mediated translational repression. Hence, these studies revealed for the first time insights into how an interacting protein can modulate Hfq function. Moreover, Crc is shown to interfere with binding of a regulatory RNA to Hfq, which bears implications for riboregulation. These results are discussed in terms of a working model, wherein Crc prioritizes the function of Hfq toward utilization of favored carbon sources.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Binding Sites
  • Bordetella pertussis / genetics
  • Bordetella pertussis / metabolism
  • Carbohydrate Metabolism / genetics
  • Catabolite Repression*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression Regulation, Bacterial
  • Host Factor 1 Protein / chemistry
  • Host Factor 1 Protein / genetics*
  • Host Factor 1 Protein / metabolism
  • Kinetics
  • Models, Molecular
  • Nucleotide Motifs
  • Protein Binding
  • Protein Biosynthesis*
  • Protein Interaction Domains and Motifs
  • Protein Structure, Secondary
  • Pseudomonas aeruginosa / genetics*
  • Pseudomonas aeruginosa / metabolism
  • RNA, Bacterial / chemistry
  • RNA, Bacterial / genetics*
  • RNA, Bacterial / metabolism
  • Regulon
  • Repressor Proteins / chemistry
  • Repressor Proteins / genetics*
  • Repressor Proteins / metabolism
  • Transcriptome


  • Bacterial Proteins
  • Host Factor 1 Protein
  • RNA, Bacterial
  • Repressor Proteins
  • crc protein, Pseudomonas