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Project #12833
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#12833 : Training project for bacterial ChIP-seq Analysis on Streptococcus agalactiae
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Name of Applicant : Maria vittoria Mazzuoli
Date of application : 14-01-2019
Unit : Biology of Gram-Positive Pathogens
Location : Duclaux aile Fourneau 1ere etage piƩce 27
Phone : 0644844280
@ Mail : mariavittoria.mazzuoli@pasteur.fr
@ PI-Mail : arnaud.firon@pasteur.fr

Project context and summary :

Streptococcus agalactiae (GBS) is a commensal gram-positive bacteria which asymptomatically colonize the genital and intestinal tract of healthy women. However, GBS is 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 relies on a highly dynamic regulation of colonization and virulence related genes. The major regulator identified to date is the two-component system CovSR (Control of Virulence Sensor and Regulator). The transcription of almost 15% of the genome is dependent on CovR, but the genes directly regulated by CovR and the regulation of CovR-DNA binding by CovR-phosphorylation are ill-defined. To characterize the genome-wide CovR binding sites, we performed chromatin immunoprecipitation and sequencing (ChIP-Seq). Technically, we developed an epitope-tagged and functional form of CovR expressed under an inducible promoter. Quantitative PCR on ChIP samples (ChIP-qPCR) and small-scale footprint experiments revealed an enrichment of binding regions on specific promoters whose transcription are CovR-dependent. Sequencing (ChIP-seq) has been done to 1) characterize the landscape of CovR binding sites along the chromosome and to reveal the function of genes directly regulated by CovR; 2) to decipher the mechanism of regulation by performing the same experiment in strains with different level of CovR phosphorylation; and 3) to unravel an evolutionary strategy of genetic rewiring leading to the emergence of hypervirulent GBS strain by comparing the CovR direct regulon and the evolution of promoter sequences in different clinical stains.


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Service Delivery
Project Manager : claudia.chica@pasteur.fr
Project Type : Coaching
Status : Closed


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