The Crc and Hfq proteins of Pseudomonas putida cooperate in catabolite repression and formation of ribonucleic acid complexes with specific target motifs. (2nd June 2014)

• Record Type: Journal Article
• Authors: Moreno, Renata; Hernández‐Arranz, Sofía; La Rosa, Ruggero; Yuste, Luis; Madhushani, Anjana; Shingler, Victoria; Rojo, Fernando
• Is Part Of: Environmental microbiology. Volume 17:Number 1(2015:Jan.)
• Page Start: 105
• Page End: 118
• Publication Date: 2014-06-02
• Subjects: Microbial ecology -- Periodicals; Environmental Microbiology -- Periodicals; 579.17
• DOI: 10.1111/1462-2920.12499
• Languages: English
• ISSNs: 1462-2912

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>The Crc protein is a global regulator that has a key role in catabolite repression and optimization of metabolism in <italic>Pseudomonads</italic>. Crc inhibits gene expression post‐transcriptionally, preventing translation of mRNAs bearing an AAnAAnAA motif [the catabolite activity (CA) motif] close to the translation start site. Although Crc was initially believed to bind RNA by itself, this idea was recently challenged by results suggesting that a protein co‐purifying with Crc, presumably the Hfq protein, could account for the detected RNA‐binding activity. Hfq is an abundant protein that has a central role in post‐transcriptional gene regulation. Herein, we show that the <italic>P</italic><italic>seudomonas putida</italic> Hfq protein can recognize the CA motifs of RNAs through its distal face and that Crc facilitates formation of a more stable complex at these targets. Crc was unable to bind RNA in the absence of Hfq. However, pull‐down assays showed that Crc and Hfq can form a co‐complex with RNA containing a CA motif <italic>in vitro</italic>. Inactivation of the <italic>hfq</italic> or the <italic>crc</italic> gene impaired catabolite repression to a similar extent. We propose that Crc and Hfq cooperate in catabolite repression, probably through forming a stable co‐complex with RNAs containing CA motifs to result in inhibition of translation initiation.</p> </abstract>