New genes with old modus operandi. The connection between supercoiling and partitioning of DNA in Escherichia coli.
The process of partitioning bacterial sister chromosomes into daughter cells seems to be distinct from chromatid segregation during eukaryotic mitosis. In Escherichia coli, partitioning starts soon after initiation of replication, when the two newly replicated oriCs move from the cell centre to quarter positions within the cell. As replication proceeds, domains of the compact, supercoiled chromosome are locally decondensed ahead of the replication fork. The nascent daughter chromosomes are recondensed and moved apart through the concerted activities of topoisomerases and the SeqA (sequestration) and MukB (chromosome condensation) proteins, all of which modulate nucleoid superhelicity. Thus, genes involved in chromosome topology, once set aside as 'red herrings' in the search for 'true' partition functions, are again recognized as being important for chromosome partitioning in E. coli.
Dasgupta
S
S
Department of Cell and Molecular Biology, Uppsala University, Biomedical Centre, Sweden.
Maisnier-Patin
S
S
Nordström
K
K
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000235:genetics; D002868:Chromosomal Proteins, Non-Histone; D002876:Chromosomes, Bacterial / Q000502:physiology; D004261:DNA Replication / Q000502:physiology*; D004264:DNA Topoisomerases, Type I / Q000235:genetics; D004269:DNA, Bacterial / Q000502:physiology*; D004278:DNA, Superhelical / Q000502:physiology*; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D014157:Transcription Factors
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002868:Chromosomal Proteins, Non-Histone; D004269:DNA, Bacterial; D004278:DNA, Superhelical; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C067035:MukB protein, E coli; C089746:SeqA protein, E coli; D014157:Transcription Factors; D004264:DNA Topoisomerases, Type I