Non-random segregation of sister chromosomes by Escherichia coli MukBEF axial cores

Abstract

SummaryThe Escherichia coli structural maintenance of chromosomes complex, MukBEF, forms axial cores to chromosomes that determine their spatio-temporal organization. Here, we show that axial cores direct chromosome arms to opposite poles and generate the translational symmetry between newly replicated sister chromosomes. MatP, a replication terminus (ter) binding protein, prevents chromosome rotation in the longitudinal cell axis by displacing MukBEF from ter, thereby maintaining the linear shape of axial cores. During DNA replication, MukBEF-MatP action directs lagging strands towards the cell center, marked by accumulation of DNA-bound β2-clamps in the wake of the replisome, in a process necessary for translational symmetry. Finally, the ancestral template DNA strand, propagated from previous generations, is preferentially inherited by the cell forming at the old pole, dependent on MukBEF-MatP. The work demonstrates how chromosome organization-segregation fosters non-random inheritance of genetic material and provides a framework for understanding how chromosome conformation and dynamics shape subcellular organization.HighlightsLinear MukBEF axial cores are required for left-oriC-right chromosome organizationMatP prevents longitudinal nucleoid rotation by linearizing the axial coresMukBEF axial cores direct lagging strands towards the cell centerThe ancestral DNA strand is preferentially segregated to the older pole cell