The connection between dynamic DNA supercoiling and transcription is not well understood. High-resolution mapping of in vivo DNA supercoiling at transcription start sites (TSSs) now reveals that supercoils spread about 1.5 kb upstream of the TSSs of active genes. Highly expressed genes rely on topoisomerase II to dissipate dynamic supercoiling, whereas moderately expressed genes depend on topoisomerase I.
- Fedor Kouzine
- Ashutosh Gupta
- David Levens