DNA supercoiling allows enhancer action over a large distance.
Enhancers are regulatory DNA elements that can activate their genomic targets over a large distance. The mechanism of enhancer action over large distance is unknown. Activation of the glnAp2 promoter by NtrC-dependent enhancer in Escherichia coli was analyzed by using a purified system supporting multiple-round transcription in vitro. The data suggest that DNA supercoiling is an essential requirement for enhancer action over a large distance (2,500 bp) but not over a short distance (110 bp). DNA supercoiling facilitates functional enhancer-promoter communication over a large distance, probably by bringing the enhancer and promoter into close proximity.
Liu
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Y
Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, 540 East Canfield Avenue, Room 5123, Detroit, MI 48201, USA.
Bondarenko
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V
Ninfa
A
A
Studitsky
V M
VM
D001483:Base Sequence; D017931:DNA Primers; D004278:DNA, Superhelical / Q000502:physiology*; D004742:Enhancer Elements, Genetic; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
D017931:DNA Primers; D004278:DNA, Superhelical