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Project #11793
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#11793 : ChIP-seq analysis of the majour regulator of GBS virulence
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Name of Applicant : maria vittoria mazzuoli
Date of application : 29-05-2018
Unit : Biology of Gram-Positive Pathogens
Location : Duclaux aile Fourneau 1ere etage piéce 27
Phone : +6644844280
@ Mail : mariavittoria.mazzuoli@pasteur.fr
@ PI-Mail : arnaud.firon@pasteur.fr

Project context and summary :

Streptococcus agalactiae (GBS) is a gram positive-bacteria which asymptomatically colonize the genital and intestinal tract of healthy women, although the leading cause of bacterial invasive infections in newborns in developed countries. The ability of GBS to succeed both as a commensal and a pathogen can be linked to its capacity to efficiently colonize the host, while still retaining its toxic capacities for the invasive phase of the infectious process. This highly dynamic regulation relies on the major regulator of virulence gene expression, the two-component system CovSR (Control of Virulence Sensor and Regulator). The transcription of almost 15% of the genome is dependent on CovR but up to now only three genes or operons have been identified as directly CovR-regulated by a DNAse I footprint low throughput approach. To characterize the genome-wide CovR binding site, we performed chromatin immunoprecipitation and sequencing (ChIP-Seq) with an epitope-tagged and functional form of CovR expressed in a ∆covR mutant. Quantitative PCR on ChIP samples (ChIP-qPCR) revealed an enrichment of binding regions on the promoters of known target genes. Sequencing of enriched regions has been done to characterize the landscape of CovR binding sites along the chromosome and to reveal the mechanism of regulation and the function of genes directly regulated by CovR. Since CovR phosphorylation state has an important role on DNA binding affinity, defined levels of CovR expression and phosphorylation will be tested to point out low and high affinity targets and the study of different GBS genetic backgrounds will help us elucidate strain-specificities associated with bacterial meningitides in neonates.


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Project Manager : claudia.chica@pasteur.fr
Project Type : Short
Status : In Progress


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