Project description:cDNA microarray analysis to identify genes regulated by the RNA chaperone, Hfq. Four experiments were performed: 1/ Hfq+ vs Hfq- strains. 269 significantly differentially regulated genes were identified by SAM (Statistical Analysis of Microarrays), of which 120 changed more than 1.5 fold (48 increased and 72 decreased in hfq-). Amongst other genes, these experiments identified significant regulation of the sigma E and sigma 32 regulons. However, only genes induced by sigma E were similarly induced in hfq-; 8 operons repressed by sigma E were not repressed in hfq-. 2/ wt vs delta rseA. RseA is the antisigma factor for sigmaE. This comparison results in elevated steady-state levels of sigma E, and confirmed induction and repression of target regulon members. 3/ hfq+ vs hfq+ rpoE overexpression. RpoE encoding sigma E was overexpressed in an hfq+ background, confirming normal regulation of the sigma E regulon. 4/ hfq+ vs hfq- rpoE overexpression. Sigma E was overexpressed in an hfq- background. This demonstrated that 8 operons normally repressed by sigma E require hfq for this repression. The simple conclusion is that sigma E regulates small RNAs that, together with Hfq, bind target mRNAs and results in their rapid degradation. This study is detailed in Guisbert et al 2007 (J Bacteriol, 189:1963-73) Keywords: Genetic modification
Project description:Pseudomonas chlororaphis strain 30-84 is an effective biological control agent against take-all disease of wheat. In this study, we conducted an RNA-seq analysis by comparing the wild type strain with a Hfe deficient mutant. RNA-seq analysis identified over 900 genes differentially regulated by Hfq.
Project description:Co-immunoprecipitation with endogenous Hfq3xFlag in exponential, stationary, non-induced and virulence induced conditions, followed by RNA-sequencing, revealed 1697 mRNAs and 208 ncRNAs associated with Hfq. We identified 56 new ncRNAs and validated 3 Hfq-dependent trans sRNAs on by Northern blot analysis. Interestingly, 55% of the ncRNAs were encoded antisense to a protein coding sequence. Abundance of 4 asRNAs and their corresponding target mRNAs was altered upon hfq, indicating a substantial influence of Hfq on asRNA-target interactions.
Project description:Pseudomonas chlororaphis strain 30-84 is an effective biological control agent against take-all disease of wheat. In this study, we conducted an RNA-seq analysis by comparing the wild type strain with a Hfe deficient mutant. RNA-seq analysis identified over 900 genes differentially regulated by Hfq. A total of 4 samples were analyzed in AB medium + 2% casamino acids, Pseudomonas chlororaphis wild type strain (2 replicates); Pseudomonas chlororaphis ZN mutant (2 replicates).
Project description:Co-immunoprecipitation with endogenous Hfq3xFlag in exponential, stationary, non-induced and virulence induced conditions, followed by RNA-sequencing, revealed 1697 mRNAs and 208 ncRNAs associated with Hfq. We identified 56 new ncRNAs and validated 3 Hfq-dependent trans sRNAs on by Northern blot analysis. Interestingly, 55% of the ncRNAs were encoded antisense to a protein coding sequence. Abundance of 4 asRNAs and their corresponding target mRNAs was altered upon hfq, indicating a substantial influence of Hfq on asRNA-target interactions. 8 cDNA libraries were sequenced. A. tumefaciens hfq3xFlag and hfqWT (control) strains were grown to stationary and exponential growth phase and under non-induced and virulence induced conditions.
Project description:In this study, we used gel-free nanoLC-MS/MS-based proteomics to compare the protein profile of B. pertussis wild type and an isogenic hfq defective mutant strain under control an iron limited conditions. We found that Hfq affects the abundance of 302 proteins, which represents 8% of the total B. pertussis coding sequence. The absence of Hfq induced changes in the abundance of proteins involved in metabolic pathways, stress response and virulence. Hfq was also found involved in B. pertussis adaptation to iron starvation, one of the main stresses this pathogen faces inside the host. Altogether, these results indicate that B. pertussis Hfq is involved in bacterial physiological processes as well as bacterial pathogenesis.
