Chromosome organization in shape-manipulated E. Coli cells

The bacterial chromosome is spatially organized under the combined influence of protein-mediated condensation, supercoiling, and the cell-boundary confinement, but their roles have not been resolved independently in vivo.

In our lab, we study the intrinsic structure of E.Coli chromosome through cell shape manipulation, quantitative imaging and numerical simulations,. We are interested in understanding the spatial and dynamic organization of DNA in live cells. We use drugs and molecular genetics tools to disrupt the cytoskeleton of bacteria, leading to cell sizes far larger than the rod-like wild type cells. We controllably modify the cell boundary and let the nucleoids expand (Figure 1). This enables us to quantitatively study the structure and dynamics of the heterogeneous chromosome in vivo

Figure 1: Fluorescent image of E.coli cells. By relaxing the cell shape, we obtain non-rod-shape bacteria, cf. the outer cell membrane confinement (white line). Here we can resolve the E.coli nucleoid (gray) as it shows its intrinsic donut topology.

Figure 1: Fluorescent image of E.coli cells. By relaxing the cell shape, we obtain non-rod-shape bacteria, cf. the outer cell membrane confinement (white line). Here we can resolve the E.coli nucleoid (gray) as it shows its intrinsic donut topology.