 DNA
supercoiling by gyrase is linked to nucleoid compactionRogier Stuger, Conrad L. Woldringh, Coen C. van der Weijden, Norbert O.E. Vischer, Barbara M. Bakker, Rob J.M. van Spanning, Jacky L. Snoep, Hans V. Westerhoff Mol Biol Rep 29 (2002) 79-82 erratum in Mol Biol Rep 30 (2003) 133 Molecular Cell Physiology, Free University, Amsterdam, The Netherlands. Abstract The genes of E. coli are located on a circular chromosome of 4.6 million basepairs. This 1.6 mm long molecule is compressed into a nucleoid to fit inside the 1-2 μm cell in a functional format. To examine the role of DNA supercoiling as nucleoid compaction force we modulated the activity of DNA gyrase by electronic, genetic, and chemical means. A model based on physical properties of DNA and other cell components predicts that relaxation of supercoiling expands the nucleoid. Nucleoid size did not increase after reduction of DNA gyrase levels by genetic or chemical means, but nucleoids expanded upon chemical inhibition of gyrase in chloramphenicol-treated cells, indicating that supercoiling may help to compress the genome. [full-text pdf] [erratum pdf] more nucleoidology on our department website |