Open AccessTracking the Elusive Function of Bacillus subtilis Hfq
Author(s) -
Tatiana Rochat,
Olivier Delumeau,
Nara FigueroaBossi,
Philippe Naveilhan,
Lionello Bossi,
Etienne Dervyn,
Philippe Bouloc
Publication year - 2015
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0124977
Subject(s) - bacillus subtilis , biology , salmonella enterica , mutant , salmonella , microbiology and biotechnology , phenotype , rna , escherichia coli , transcriptome , genetics , gene , bacteria , gene expression
RNA-binding protein Hfq is a key component of the adaptive responses of many proteobacterial species including Escherichia coli , Salmonella enterica and Vibrio cholera . In these organisms, the importance of Hfq largely stems from its participation to regulatory mechanisms involving small non-coding RNAs. In contrast, the function of Hfq in Gram-positive bacteria has remained elusive and somewhat controversial. In the present study, we have further addressed this point by comparing growth phenotypes and transcription profiles between wild-type and an hfq deletion mutant of the model Gram-positive bacterium, Bacillus subtilis . The absence of Hfq had no significant consequences on growth rates under nearly two thousand metabolic conditions and chemical treatments. The only phenotypic difference was a survival defect of B . subtilis hfq mutant in rich medium in stationary phase. Transcriptomic analysis correlated this phenotype with a change in the levels of nearly one hundred transcripts. Albeit a significant fraction of these RNAs (36%) encoded sporulation-related functions, analyses in a strain unable to sporulate ruled out sporulation per se as the basis of the hfq mutant’s stationary phase fitness defect. When expressed in Salmonella , B . subtilis hfq complemented the sharp loss of viability of a degP hfq double mutant, attenuating the chronic σ E -activated phenotype of this strain. However, B . subtilis hfq did not complement other regulatory deficiencies resulting from loss of Hfq-dependent small RNA activity in Salmonella indicating a limited functional overlap between Salmonella and B . subtilis Hfqs. Overall, this study confirmed that, despite structural similarities with other Hfq proteins, B . subtilis Hfq does not play a central role in post-transcriptional regulation but might have a more specialized function connected with stationary phase physiology. This would account for the high degree of conservation of Hfq proteins in all 17 B . subtilis strains whose genomes have been sequenced.