Self-organised segregation of bacterial chromosomal origins.

The chromosomal replication origin region () of characterised bacteria is dynamically positioned throughout the cell cycle. In slowly growing , is maintained at mid-cell from birth until its replication, after which newly replicated sister s move to opposite quarter positions. Here, we provide an explanation for positioning based on the self-organisation of the Structural Maintenance of Chromosomes complex, MukBEF, which forms dynamically positioned clusters on the chromosome. We propose that a non-trivial feedback between the self-organising gradient of MukBEF complexes and the s leads to accurate positioning. We find excellent agreement with quantitative experimental measurements and confirm key predictions. Specifically, we show that s exhibit biased motion towards MukBEF clusters, rather than mid-cell. Our findings suggest that MukBEF and s act together as a self-organising system in chromosome organisation-segregation and introduces protein self-organisation as an important consideration for future studies of chromosome dynamics.