K. Ohsumi et al., Different localization of SeqA-bound nascent DNA clusters and MukF-MukE-MukB complex in Escherichia coli cells, MOL MICROB, 40(4), 2001, pp. 835-845
MukF, MukE and MukB proteins form a complex that may participate in the org
anization of folded sister chromosomes in Escherichia coli, We have found t
hat a MukB-GFPuv4 fusion protein is observed as discrete fluorescent foci,
which are localized within cellular spaces occupied by nucleoids, but not a
t the constriction site of cell division in living cells. In contrast, MukB
-GFPuv4 is distributed throughout the whole cell when either MukF or MukE i
s absent. Statistical analysis revealed that most newborn cells have two fo
ci of mukB-gfpUV4 at one-quarter and three-quarter positions in the cell le
ngth and one focus of SeqA-bound nascent DNA at or near the middle of the c
ell. Subsequently, the single SeqA focus divides into two foci, and then th
ese migrate to the one-quarter and three-quarter positions. Before cell div
ision, most long cells have two SeqA foci and four MukB-GFPuv4 foci, In ear
ly stationary phase, SeqA foci disappear, but one or two foci of MukB-GFPuv
4 remain. We discuss the reorganization and proper arrangement of folded si
ster chromosome in the cell quarter positions, which are performed after re
lease from the long-time cohesion of sister chromosomes.