Project description:The genus Francisella includes several species that cause zoonotic diseases and that have evolved to develop different strategies for survival within the host cells. Despite the critical importance of the diseases caused by members of the genus Francisella, the DNA repair mechanisms of this pathogen remain understudied. In this work, the transcriptional response of Francisella hispaniensis to the DNA-damaging agent ciprofloxacin was studied using RNA sequencing. Among the differentially expressed genes, we identified a S24 family peptidase-encoding gene. Electrophoretic mobility shift assays demonstrated that the product of this gene specifically binds to the palindromic sequence GTG-N11-CAC present in its promoter region, resulting in autoregulation. In silico analyses revealed that this S24 peptidase, here termed FddR, is most likely a co-opted phage repressor that implements a DNA-damage response across the Francisella genus. Our results provide insights into the SOS repair system of Francisella spp. and suggest that the identified S24 family peptidase is a direct regulator of the DNA damage response in F. hispaniensis.
Project description:To understand differences of gene expression profiles between Francisella strains RNA profiles of Francisella strains were generated by deep sequencing, in triplicate, using NovaSeq6000. qRT–PCR validation was performed using SYBR Green assays. Our study represents the first detailed differential transcriptomic analysis of Francisella strains , with biologic replicates, generated by RNA-seq technology.
Project description:Francisella tularensis may enter the body thorugh the lungs and cause fatal infection. In this study the inflammatory response to the virulent strain of Francisella (Schu4) was mapped over a 96h time-course using a custom microarray.
Project description:The goal of this study is to determine the host response of human epithelial cells during infection with Francisella Tularensis. For this purpose, A549 human epithelial cell line was infected with Francisella tularensis spp. holarctica strain LVS for different times of infection, in duplicates. At different times post infection (0.5/1/3/6/12/24 hours post infection) cells were harvested and total RNA was extracted. RNA-seq libraries were constructed and sequencing of 100bp paired-end was performed on the Illumina NovaSeq 6000 system. Sequencing yielded about 22M reads per sample that were mapped to the human genome (Human: GRCh38) resulting with the identification of 21,066 transcripts. The expression of the infected samples was compared to mock sample, and RNA ratios were clustered using partitioning clustering. This approach allowed clustering of the cellular transcripts into 5 distinct classes based on similarities in temporal expression profiles. We next carried out GO term enrichment analysis for each of these five cluster. Our study represents the first detailed analysis of human epithelial response to Francisella tularensis infection, and provide a framework for comparative investigations of genes and mechanisms that may contribute to the infection.
