Peter L. Graumann
from: Bacillus: Cellular and Molecular Biology (Edited by: Peter Graumann). Caister Academic Press, U.K. (2007)
The Bacillus subtilis chromosome with its 2 mm contour length is compacted into a 1 µm large nucleoid, and sister chromosomes are separated into opposite cell poles during ongoing replication through an active intracellular machinery. The machinery consists of several elements that have a defined subcelluar localization, and appear to work hand in hand. Replication occurs in the centrally located replication apparatus that optimally positions duplicated chromosome regions to be moved towards opposite cell poles, through an as yet unknown motor that may involve bacterial actin-like filaments. Separated regions appear to be compacted within each cell half by the SMC condensation complex, which forms subcellular assemblies within each cell half. Dedicated recombination enzymes, topoisomerases and a DNA pump ensure complete separation of occurring chromosome dimers, chromosome termini that are intertwined or chromosomes that may be trapped within the division septum, respectively read more ...