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Accueil > Séminaires

Département Biologie des Génomes

par Clubs génome, EQYY - publié le , mis à jour le


  • Vendredi 18 octobre 11:00-12:00 - Heath MURRAY - Newcastle University, Royaume Uni

    Identification of a basal system for bacterial chromosome origin unwinding

    Résumé : Genome duplication is essential for cell proliferation and DNA synthesis is generally initiated by dedicated replication proteins at specific loci termed origins. In bacteria the master initiator DnaA binds the chromosome origin (oriC) and unwinds the DNA duplex to permit helicase loading. However, despite decades of research it remained unclear how the information encoded within oriC guides DnaA-dependent strand separation. To address this fundamental question, we took a systematic genetic approach in vivo and identified the core set of essential sequence elements within the Bacillus subtilis chromosome origin unwinding region. Using this information we then show in vitro that the minimal replication origin sequence elements are necessary and sufficient to promote the mechanical functions of DNA duplex unwinding by DnaA. Because the basal DNA unwinding system characterized here appears to be conserved throughout the bacterial domain, this discovery provides a framework for understanding oriC architecture, activity, regulation and diversity.

    Contact : Jean-Luc FERAT (jean-luc.ferat

    Lieu : Salle des séminaires - bâtiment 26 - Campus de Gif-sur-Yvette

  • Vendredi 15 novembre 11:00-12:00 - David LALAOUNA - Institut de Biologie Moléculaire et Cellulaire, Strasbourg

    The double life of bacterial RNA transcripts

    Résumé : Discovered in the early 80’s, small regulatory RNAs (sRNAs) are depicted as key actors in virtually all aspect of bacterial physiology (e.g. primary or secondary metabolism, cell division, virulence) [1-2]. These 50 to 500 nt-long RNA fragments are mostly involved in the post-transcriptional regulation of a subset of messenger RNAs forming their interactomes.
    Bacterial regulatory RNAs have first been characterized as exclusively originating from intergenic regions. However, recent high-throughput screenings revealed that other loci, such as untranslated regions of mRNAs [3] or transcribed spacers of tRNA transcripts [4], also serve as a source of functional regulatory RNAs.
    [1] Carrier et al., 2018. Annu Rev Microbiol. 72:141-161
    [2] Wagner and Romby, 2015. Adv Genet. 90:133-208
    [3] Lalaouna et al., 2019. NAR 47:9871-9887
    [4] Lalaouna et al., 2015. Mol Cell 58:393-405

    Contact : Philippe BOULOC (philippe.bouloc

    Lieu : Salle A. Kalogeropoulos - bâtiment 400 - Campus d'Orsay

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