Project description:The enterococci comprise a genus of 49 low-GC content Gram-positive commensal species within the Firmicutes phylum that are known to occupy diverse habitats, notably the gastrointestinal core microbiota of nearly every phylum, including human. Of particular clinical relevance are two rogue species of enterococci, Enterococcus faecalis and the distantly related Enterococcus faecium, standing among the nefarious multi-drug resistant and hospital-acquired pathogens. Despite increasing evidence for RNA-based regulation in the enterococci, including regulation of virulence factors, their transcriptome structure and arsenal of regulatory small sRNAs (sRNAs) are not thoroughly understood. Using dRNA-seq, we have mapped at single-nucleotide resolution the primary transcriptomes of E. faecalis V583 and E. faecium AUS0004. We identified 2517 and 2771 transcription start sites (TSS) in E. faecalis and E. faecium, respectively. Based on the identified TSS, we created a global map of s70 promoter motifs. We also revealed features of 5’ and 3’UTRs across the genomes. The transcriptome maps also predicted 150 and 128 sRNA candidates in E. faecalis and E. faecium, respectively, some of which have been identified in previous studies and many of which are new. Finally, we validated several of the predicted sRNAs by Northern Blot in biologically relevant conditions. Comprehensive TSS mapping of two representative strains will provide a valuable resource for the continued development of RNA biology in the Enterococci.
Project description:Analysis of changes in gene expression in Enterococcus faecalis OG1 delta-EF2638 mutant compared to wild-type OG1 strain. The deletion mutant has a growth defect when grown with aeration The mutant presented in this study is described and characterized in Vesic, D. and Kristich, C.J. 2012. A Rex-family transcriptional repressor influnces H2O2 accumulation by Enterococcus faecalis. (submitted for publication)
Project description:To investigate the transcriptional changes that Enterococcus faecalis undergoes during agar surface-penetration, which promote cell envelope remodeling and tolerance to stress.
Project description:This study was undertaken to identify how gene expression of the urothelial cells respond to Enterococcus infection over the course of infection. 239 hypervariable (HV) genes were found to vary significantly over the time points, indicating a biological role in infection. Correlational clustering showed these HV genes fell into distinct families indicating a defined sequence of events following infection. Early events (0-1.5 hours post infection) were associated with upregulation of not well-known but bladder-associated genes which represented early immune response, cytoskeleton remodeling and cell cycle. Up- and downregulated genes at the middle time period (1.5-8 hours post infection) represented a variety of processes, from immune response/suppression, cell cycle/apoptosis to metabolism and cytoskeleton remodeling. Several transcription factors point to multiple pathways activation. At the late time points (8-10 hours post infection) downregulated genes represented major events of cell death, matrix degradation and immune response decline. Confocal microscopy confirms major cell death at these time points. Several events and pathways, like immune response suppression or cytoskeleton remodeling via Wnt/β-catenin and/or Rho/Rac pathway, were identified throughout the time course of HUC infection by Enterococcus. Those may be new targets for preventing and/or cure Enterococcus caused pathology. Keywords: Enterococcus, time course, microarray, infection, gene expression
Project description:To further investigate the homeostatic response of E. faecalis to Fe exposure, we examine the whole-genome transcriptional response of wild-type (WT) exposed to non toxic Fe excess. This experiment correspond the work titled Transcriptomic response of Enterococcus faecalis to iron excess (work in preparation) A four chip study using total RNA recovered from four separate wild-type cultures of Enterococcus faecalis OG1RF, two controls samples (N medium growth) and two iron samples (N medium gowth with 0.5 mM Fe-NTA). Each chip measures the expression level of 3,114 genome genes from Enterococcus faecalis strain V583 (A7980-00-01).