Linda Delimi will present her PhD thesis entitled: Biophysical modeling of the auto-assembly of DNA-protein complexes driving bacterial DNA segregation

In bacteria, DNA segregation mainly relies on ParABS systems to faithfully partition DNA molecules during cell division. Our objective is to achieve a holistic, quantitative and molecular understanding of the mechanism driving the main bacterial DNA segregation system by using integrative and multidisciplinary approaches. We will perform biophysical modeling using the tools of theoretical physics. Our collaborators in the team of Jean-Yves BOUET (CBI, Toulouse) will perform experiments in genetics and genomics, cell biology and biochemistry to test our predictions. Built on an established collaboration, we aim to decipher the mechanisms that (i) drive the auto-assembly of the nucleoprotein complexes (ParB proteins) involved in the partition of the archetypical ParABS system of the plasmid F in Escherichia coli. This part involves a liquid-liquid phase separation of proteins on a polymer, and (ii) the subsequent splitting and positioning of complexes on either side of the division plane (through the action of ParA proteins). This part involves the coupled dynamics of different protein species. We will investigate both the interplay between the two dynamic auto-assemblies, ParA and ParB, that ensures DNA segregation, and the formation and inheritance of membrane-less organelles.

Thesis co-supervised by Jean-Charles Walter et Jean-Yves BOUET