#supercoiling

Twists and turns of life: Patterns of DNA supercoiling

"A bend and a twist, then stretch and turn, now relax". What sounds like a series of exercise instructions, are also words that describe the various shapes a piece of DNA can assume. The classic double helix structure that one associates with DNA is but an extremely limited view of its physical 'shape'. The molecule that holds the codes of life is capable of further winding itself into myriad complex shapes called 'supercoils' that are capable of affecting gene expression patterns. Now, researchers from the National Centre for Biological Sciences (NCBS), Bangalore, and the National Institutes of Health (NIH), USA, have elucidated this pattern of supercoiling across the genome of the much studied bacterium E. coli.

"We have measured DNA supercoiling at a fine-scale resolution in bacteria for the first time. This study provides proof-of-concept that the supercoiling of a genome is not uniform and that it varies locally across genes. It also provides evidence to support the hypothesis that bacterial cells could be regulating gene expression and their own physiologies by altering the structure of their genomes," says Avantika Lal, the first author of the publication in the journal Nature Communications that details these findings.