In eukaryotes, motifs such as silencers, enhancers and locus control regions act over thousands of base pairs to regulate adjacent genes; insulators limit such effects, and barriers confine repressive heterochromatin to particular chromosomal segments. Recent results show that many of these motifs are nongenic transcription units, and two of them directly contact their targets lying further dow...

Significance Positive and negative supercoiling refers to the overwinding or underwinding, respectively, of a DNA double helix. Supercoiling is important ubiquitous, as all cells, from bacterial human, deploy proteins keep their genome negatively supercoiled facilitate transcription replication. Additionally, polymerase transcribes gene, its action generates twin domains supercoils opposite sig...