Self-organisation as the basis of bacterial chromosomal segregation
Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics
Metabolism, Biochemistry and Genetics of Microorganisms
Final Report Abstract
The project aimed to understand the mechanisms of DNA segregation, focusing on low-copy plasmids and the ParABS partitioning system. Using advanced microscopy and computational modelling, we revealed that F plasmid is regularly positioned along the length of the cell by an effective spring-like force. A new unifying model could explain this and other diverse plasmid behaviors, such as oscillation and diffusion motion, and predicted a transition to oscillatory dynamics at low plasmid concentrations, which was confirmed experimentally. The study also uncovered a partitioning mechanism where the DNA-binding protein ParA collectively migrates between the lobes of bilobed nucleoids, promoting equal plasmid distribution. This findings made use of a tool we developed for the accurate tracking of replicating DNA loci. This also provided new insights into plasmid copy number control and bacterial chromosome replication dynamics. Overall, these findings advance our understanding of DNA segregation and offer tools for broader applications in chromosome biology.
Publications
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High-throughput imaging and quantitative analysis uncovers the nature of plasmid positioning by ParABS. eLife, 11.
Köhler, Robin; Kaganovitch, Eugen & Murray, Seán M.
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★Track: Inferred counting and tracking of replicating DNA loci. Biophysical Journal, 122(9), 1577-1585.
Köhler, Robin; Sadhir, Ismath & Murray, Seán M.
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Plasmid partitioning driven by collective migration of ParA between nucleoid lobes. Proceedings of the National Academy of Sciences, 121(18).
Köhler, Robin & Murray, Seán M.
