Laboratoire de Chimie Bactérienne UMR 7283

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MicAtAGlance

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7 février 2019: 1 événement

séminaire

  • Séminaire LCB

    Jeudi 7 février 14:00-15:00 - Emanuele Biondi

    Séminaire LCB : A new bacterial regulator controlling cell cycle and division in Sinorhizobium meliloti

    Résumé :

    Sinorhizobium meliloti is a gram-negative bacterium able to fix nitrogen in symbiosis with plants. It belongs to the class Alphaproteobacteria showing asymmetrical cell division at every cell cycle. In S. meliloti cell cycle and cell division are controlled by a complex regulatory network, in which, at the center, the master regulator CtrA plays a crucial role activating cell division, motility and repressing the replication of DNA. Among many regulators, the kinase DivJ acts as a repressor of CtrA activity.
    By a genetic screening, selecting for Tn mutations able to rescue the growth defect of delta-divJ, we identified an insertion in the C-terminal region of the gene we named DivJ growth suppressor (digS). We showed that complete deletion of digS is lethal in S. meliloti and cells depleted of DigS showed a dramatic “mini cells” phenotype, suggesting a clear cell division defect. In this seminar we propose that DigS controls negatively DNA replication and Cell division by interacting with CtrA and the division ring formation factor FtsZ2.
    In conclusion a new regulator, DigS, plays a crucial role in coordination of cell cycle and cell division in S. meliloti and possibly in other members of the class Alphaproteobacteria, including Brucella and Agrobacterium.

    Lieu : Salle Georges Morin

    En savoir plus : Séminaire LCB

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