Proteomic analysis of Hfq-regulon in B. pertussis

LAMBERTI Y.; SURMANN K.; SURMANN K.; ALVAREZ HAYES J; BLANCÁ, B.; ALVAREZ HAYES J; BLANCÁ, B.; LAMBERTI Y.

Simposio; 12th International Symposium on Bordetella; 2019

Regulation of gene expression based on small non-coding RNA (sRNA) is a mechanism that led bacteria rapidly response to changes in the environmental conditions. Most of Gram-negative bacteria sRNA-mediated regulation requires the cofactor RNA-binding protein Hfq. Previous transcriptomic studies showed that Bordetella pertussis Hfq is involved in the regulation of expression of a wide number of genes. However, since Hfq acts at post-transcriptional level the changes observed at transcriptomic level may not necessarily correlate with alterations in protein profiles. In the present study, by mean of gel-free nanoLC-MS/MS-based proteomics we analyzed and compared the protein profiles of B. pertussis wild type and its isogenic hfq defective deletion mutant strains. We found that the absence of Hfq induce changes in the abundance of 302 (out of 1084) proteins. Among them, we identified proteins involved in cell wall biogenesis, stress response and virulence, all of them processes relevant in host-pathogen interaction, suggesting that Hfq is critical in B. pertussis pathogenesis. We also study the role of Hfq in B. pertussis proteome adaptation to iron starvation, a stress condition that bacteria face inside host, and found a significant number of proteins regulated by this post-transcriptional regulator during this growth condition. Importantly, the abundance of many bacterial virulence factors whose abundance changed in response to iron limitation was found to be dependent on Hfq. Altogether, these results indicated that Hfq regulates a significant portion of B. pertussis proteome (8% of total B. pertussis coding sequences) and that this protein is important in the regulation of bacterial factors involved in host colonization.