title: Shape and compaction of Escherichia coli nucleoids.
abstract: The genomic DNA in cells of Escherichia coli is localized in one or two compact, phase-like regions with characteristic shapes. Nucleoids undergo progressive changes in shape and compaction in the presence of drugs such as chloramphenicol or puromycin. Forces which influence nucleoid shape and compaction are reviewed, with particular emphasis on crowding effects of the cytoplasm and confinement effects of the cell envelope. Based in part on the theory of Kornyshev and Leikin for interaction between DNA duplexes, the folding of DNA caused by binding of DNA-associated proteins is suggested to antagonize DNA condensation and, thereby, increase access to DNA sequences. These views are incorporated into a working model for nucleoid organization.
authors.affiliation: Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0560, USA.
authors.forename: Steven B
authors.initials: SB
authors.lastname: Zimmerman
mesh_terms: D002876:Chromosomes, Bacterial / Q000648:ultrastructure; D042003:DNA Packaging / Q000502:physiology; D004269:DNA, Bacterial / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics* / Q000648:ultrastructure*; D008954:Models, Biological; D008958:Models, Molecular
chemical_list: D004269:DNA, Bacterial