Project description:Swarming motility by the urinary tract pathogen Proteus mirabilis has been a long-studied, but little understood phenomenon. On agar, a P. mirabilis colony grows outward in a bullseye pattern formed by consecutive waves of rapid swarming followed by consolidation into shorter cells. To examine differential gene expression in these growth phases, a microarray, constructed based on the completed genome sequence and annotation, was undertaken. RNA from 1) broth-cultured, or 2) swarming cells was extracted to assess transcription during each of these growth states. Overall design: Five independent arrays (biological replicates) were analyzed for broth-cultured versus swarming P. mirabilis HI4320.
Project description:Swarming motility by the urinary tract pathogen Proteus mirabilis has been a long-studied, but little understood phenomenon. On agar, a P. mirabilis colony grows outward in a bullseye pattern formed by consecutive waves of rapid swarming followed by consolidation into shorter cells. To examine differential gene expression in these growth phases, a microarray, constructed based on the completed genome sequence and annotation, was undertaken. RNA from 1) broth-cultured, or 2) consolidation-phase cells was extracted to assess transcription during each of these growth states. Overall design: Five independent arrays (biological replicates) were each analyzed for broth-cultured vs consolidation-phase P. mirabilis.
Project description:This series of microarrays compares gene expression by the bacterial pathogen Proteus mirabilis when the transcriptional regulator mrpJ is deleted or induced to levels found during experimental urinary tract infection. The enteric bacterium Proteus mirabilis is associated with a significant number of catheter-associated urinary tract infections. Strict regulation of the antagonistic processes of adhesion and motility, mediated by fimbriae and flagella, respectively, is essential for successful disease progression. Previously, the transcriptional regulator MrpJ, which is encoded by the mrp fimbrial operon, has been shown to repress both swimming and swarming motility. Here we show that MrpJ affects a wide array of cellular processes beyond adherence and motility. Microarray analysis found that expression of mrpJ mimicking expression levels that occur during UTI leads to differential expression of 217 genes related to, among others, bacterial virulence, type VI secretion and metabolism. We probed the molecular mechanism of transcriptional regulation through MrpJ using reporter assays and chromatin immunoprecipitation (ChIP). Two virulence-associated target genes, the flagellar master regulator flhDC and mrp itself, appear to be regulated through a binding site proximal to the transcriptional start, complemented by a more distantly situated enhancer site. Furthermore, an mrpJ deletion mutant colonized the bladders of mice at significantly lower levels in a transurethral model of infection. Additionally, we observe that mrpJ is widely conserved in a collection of recent clinical isolates, leading us to conclude that our results elucidate an unanticipated role of MrpJ as a global regulator of P. mirabilis virulence. Four biological replicates were analyzed for each set of arrays (P. mirabilis HI4320 wild type vs. ΔmrpJ, and vector pLX3607 vs. mrpJ plasmid pLX3805).
Project description:We identified genome-wide binding regions of NdgR in Streptomyces coelicolor using chromatin immunoprecipitation sequencing (ChIP-seq). We constructed 6×myc-tagged NdgR strain using homologous recombination with myc-tagging vector. Analysis of the sequencing data aligned to Streptomyces coelicolor genome database (NC_003888). Overall design: 6x-myc tagged Streptomyces coelicolor M145 was cultured on solid minimal media supplemented with N-acetylglucosamine and asparagine during 36hrs. Anti-myc antibody (9E10) was used for immunoprecipitation (IP). IP-DNA was sequenced using Illumina Genome Analyzer Ⅱx
Project description:The enteric bacterium Proteus mirabilis is a common cause of complicated urinary tract infections. In the study, microrarrays were used to analyze P. mirabilis gene expression in vivo from experimentally infected mice. Urine was collected at 1, 3, and 7d postinfection, and RNA was isolated from bacteria in the urine for transcriptional analysis. Across 9 microarrays, 471 genes were upregulated and 82 were downregulated in vivo compared to in vitro broth culture. Genes upregulated in vivo encoded MR/P fimbriae, urease, iron uptake systems, amino acid and peptide transporters, pyruvate metabolism, and portions of the TCA cycle. Flagella were downregulated. Ammonia assimilation gene glnA (glutamine synthetase) was repressed in vivo while gdhA (glutamate dehydrogenase) was upregulated in vivo. Contrary to our expectations, ammonia availability due to urease activity in P. mirabilis did not drive this gene expression. A gdhA mutant was growth-deficient in minimal medium with citrate as the sole carbon source, and loss of gdhA resulted in a significant fitness defect in the mouse model of urinary tract infection. Unlike Escherichia coli, which represses gdhA and upregulates glnA in vivo and cannot utilize citrate, the data suggest that P. mirabilis uses glutamate dehydrogenase to monitor carbon-nitrogen balance, and this ability contributes to the pathogenic potential of P. mirabilis in the urinary tract. Voided urine from female CBA/J mice infected with Proteus mirabilis was collected and pooled in RNA stabilizing reagent (RNAprotect). Urine was collected at 1, 3, and 7 d postinfection. RNA was isolated from urine and log-phase LB cultures, converted to cDNA, and labeled with CyDye. Three arrays were completed per time point (9 arrays total). Slides were scanned with a ScanArray Express microarray scanner (Perkin Elmer) at 10 μm resolution and quantified using ScanArray Express software. Resulting data were normalized by total intensity and median spot intensities were identified using MIDAS (v. 2.22) software.