IMR Press / FBL / Volume 12 / Issue 7 / DOI: 10.2741/2398

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on as a courtesy and upon agreement with Frontiers in Bioscience.

Supercoil-driven DNA structures regulate genetic transactions
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1 Laboratory of Pathology, National Cancer Institute, Bethesda, MD 20892-1500, USA
Academic Editor:Sergei Mirkin
Front. Biosci. (Landmark Ed) 2007, 12(7), 4409–4423;
Published: 1 May 2007
(This article belongs to the Special Issue DNA structures, genome instability and human disease)

DNA is a living molecule, writhing, twisting and bending in response to the physical forces applied to it by genetic processes. Twisting and untwisting of the double helix by powerful molecular motors generates, at least transiently, high levels of torques. Although under relaxed conditions the double helical B-form is the predominant conformation of DNA, in response to physical stress, B-DNA strains inhomogeneously, adopting a variety of alternative structures. These structures are the sites of genetic damage that increase the fragility of the genome, but they may also participate in physiological processes performing functions not achievable using conventional duplex. The dynamic response of DNA to supercoiling forces contributes to control of genes such as c-myc whose physiological levels must be precisely regulated.

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