Analysis of the time intervals between nucleoid partitioning, Z-ring formation and morphological cell division in Escherichia coli

The cell division process in Escherichia coli relies on the timely execution of nucleoid partitioning and Z-ring formation. From multi-modal time-lapse microscopy images of cells with FtsZ-GFP proteins and expressing HupA-mCherry, a fluorescent variant of a nucleoid-associated protein, we studied the mean and cell-to-cell variability of the time lag between the partitioning of the nucleoid and the formation of the Z-ring. We find that these variables are affected by the size of the nucleoid(s) relative to the cell size. Our results are in agreement with recent research that shows that the nucleoid plays a role in the location of the point of cell division, by showing that the nucleoid morphology also affects when the Z-ring forms, following nucleoid partitioning. We conclude that, in E. coli, the morphology of the nucleoid(s) plays a key role in the proper functioning of the process of cell division, both spatially and temporally.