Skip to Main content Skip to Navigation

Réseaux de régulation et éléments intégratifs et conjugatifs de la famille TnGBS dans l'adaptation de Streptococcus agalactiae

Abstract : S. agalactiae (GBS) was initially described as responsible for bovine mastitis, but is now recognized as a leading cause of infections in neonates causing pneumonia, septicemia, and meningitidis. However, this bacterium is primarily a commensal of the human digestive and genitourinary tracts. To colonize and to adapt to this broad range of environments, GBS utilizes transcriptional regulators. Using transcriptomic approaches, we have characterized some of these regulatory systems. In particular, we have demonstrated that the D-alanylation of the LTA is under the control of a dual feedback loop involving the two TCS DltRS and CiaRH. This dual regulation ensure a fine-turning of the expression of the dlt operon expression and consequently of the net charge of the bacterial cell surface. We have also shown that the loci encoding the virulence factors Srr and PI-2a are regulated by two transcription factors of RofA-like family, and also regulated by CovRS regulatory system belonging to the core genome. The EGMs are the major contributor of genome evolution by lateral gene transfer. We have characterized a new family of ICEs ,the TnGBS, corresponding to the first family of ICEs whose excision/integration is mediated by a DDE transposase. Another characteristic of this family is their insertion specificity upstream promoters sequences. The characterization and the comparative analysis of TnGBS related elements led to define the proteins implicated in the different steps of the conjugation process. The TnGBS related elements can be classified in subgroups sharing the tranposase but associated with two different conjugation machineries
Document type :
Complete list of metadatas
Contributor : Theses Bupmc <>
Submitted on : Thursday, May 30, 2013 - 2:48:02 PM
Last modification on : Thursday, December 10, 2020 - 10:52:45 AM
Long-term archiving on: : Saturday, August 31, 2013 - 6:15:12 AM


  • HAL Id : tel-00828193, version 1


Violette da Cunha. Réseaux de régulation et éléments intégratifs et conjugatifs de la famille TnGBS dans l'adaptation de Streptococcus agalactiae. Biologie cellulaire. Université Pierre et Marie Curie - Paris VI, 2012. Français. ⟨NNT : 2012PA066014⟩. ⟨tel-00828193⟩



Record views


Files downloads