Chromosome condensation in the absence of the non-SMC subunits of MukBEF.
MukBEF is a bacterial SMC (structural maintenance of chromosome) complex required for chromosome partitioning in Escherichia coli. We report that overproduction of MukBEF results in marked chromosome condensation. This condensation is rapid and precedes the effects of overproduction on macromolecular synthesis. Condensed nucleoids are often mispositioned; however, cell viability is only mildly affected. The overproduction of MukB leads to a similar chromosome condensation, even in the absence of MukE and MukF. Thus, the non-SMC subunits of MukBEF play only an auxiliary role in chromosome condensation. MukBEF, however, was often a better condensin than MukB. Furthermore, the chromosome condensation by MukB did not rescue the temperature sensitivity of MukEF-deficient cells, nor did it suppress the high frequency of anucleate cell formation. We infer that the role of MukBEF in stabilizing chromatin architecture is more versatile than its role in controlling chromosome size. We further propose that MukBEF could be directly involved in chromosome segregation.
Wang
Qinhong
Q
University of Oklahoma, Department of Chemistry and Biochemistry, 620 Parrington Oval, Norman, OK 73019, USA.
Mordukhova
Elena A
EA
Edwards
Andrea L
AL
Rybenkov
Valentin V
VV
D002868:Chromosomal Proteins, Non-Histone / Q000502:physiology*; D002876:Chromosomes, Bacterial / Q000235:genetics*; D004261:DNA Replication; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000502:physiology*; D011500:Protein Synthesis Inhibitors; D012097:Repressor Proteins / Q000502:physiology*
D002868:Chromosomal Proteins, Non-Histone; D029968:Escherichia coli Proteins; C067035:MukB protein, E coli; D011500:Protein Synthesis Inhibitors; D012097:Repressor Proteins; C087115:mukE protein, E coli; C087116:mukF protein, E coli