Expositor: Baptiste Guilhas (Center for Structural Biochemistry – CNRS/INSERM/UM, Montpellier, France.)
Fecha: Martes 22/08/2017 – 11.30 hs.
Besides their single chromosome, bacteria carry plasmids that are small DNA molecules replicating autonomously. For high-copy number plasmids, random diffusion is sufficient to ensure both daughter cells inherit at least one plasmid copy following cell division, while low-copy number plasmids (i.e typically one or two copies per cells) encode dedicated partition (Par) systems to actively segregate DNA and therefore to ensure their faithful transmission. F-plasmids regulate their positions using the highly conserved ParABS system which encodes only two proteins, ParA and ParB, and a parS partition site. Together they must precisely position newly replicated plasmids before the creation of the division septum at the middle of the cell. Despite extensive studies, we still lack an understanding of the coordination between the bacterial cell cycle and the low-copy number plasmids segregation. Here, we investigate their spatial and temporal regulation using fluorescence microscopies and stochastic simulations.