Sommaire:

In spite of much effort, many aspects of chromosome segregation in bacteria remain unclear. Like many other bacteria, the chromosomal origin of replication in Escherichia coli is dynamically positioned throughout the cell cycle. Initially maintained at mid-cell, where replication occurs, origins are subsequently partitioned to opposite quarter positions. However the mechanism underlying this is unknown. Here, we provide an explanation based on the self-organisation of the Structural Maintenance of Chromosomes complex, MukBEF. We propose that a non-trivial feedback between the self-organising MukBEF gradient and the origins leads to accurate positioning and partitioning as an emergent property. We find excellent agreement with quantitative experimental measurements and confirm key predictions. In particular, we show that origins exhibit biased motion towards MukBEF, rather than mid-cell, consistent with the model. Overall, our findings suggest that MukBEF and origins act together as a self-organising system for chromosome segregation and introduces protein self-organisation as an important consideration for future studies of chromosome dynamics.

Pour plus d'informations, merci de contacter Walter J.-C.