title: The RNA chaperone Hfq is important for growth and stress tolerance in Francisella novicida.
abstract: The RNA-binding protein Hfq is recognized as an important regulatory factor in a variety of cellular processes, including stress resistance and pathogenesis. Hfq has been shown in several bacteria to interact with small regulatory RNAs and act as a post-transcriptional regulator of mRNA stability and translation. Here we examined the impact of Hfq on growth, stress tolerance, and gene expression in the intracellular pathogen Francisella novicida. We present evidence of Hfq involvement in the ability of F. novicida to tolerate several cellular stresses, including heat-shock and oxidative stresses, and alterations in hfq gene expression under these conditions. Furthermore, expression of numerous genes, including several associated with virulence, is altered in a hfq mutant strain suggesting they are regulated directly or indirectly by Hfq. Strikingly, we observed a delayed entry into stationary phase and increased biofilm formation in the hfq mutant. Together, these data demonstrate a critical role for Hfq in F. novicida growth and survival.
authors.affiliation: Department of Microbiology, Southern Illinois University, Carbondale, Illinois, United States of America.
authors.forename: Jacob R
authors.initials: JR
authors.lastname: Chambers
authors.forename: Kelly S
authors.initials: KS
authors.lastname: Bender
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics; D000595:Amino Acid Sequence; D018441:Biofilms / Q000254:growth & development; D004251:DNA Transposable Elements / Q000235:genetics; D004926:Escherichia coli; D005603:Francisella / Q000235:genetics / Q000254:growth & development* / Q000502:physiology*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics; D005816:Genetic Complementation Test; D035001:Host Factor 1 Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018832:Molecular Chaperones / Q000378:metabolism*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics; D010641:Phenotype; D012329:RNA, Bacterial / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013312:Stress, Physiological / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: D004251:DNA Transposable Elements; D035001:Host Factor 1 Protein; D018832:Molecular Chaperones; D012329:RNA, Bacterial