Related Experiment Video
Updated: Sep 15, 2026

CRISPR-Mediated Reorganization of Chromatin Loop Structure
Published on: September 14, 2018
Transcription regulation by inflexibility of promoter DNA in a looped complex
Abstract:
The gal operon of Escherichia coli is negatively regulated by repressor binding to bipartite operators separated by 11 helical turns of DNA. Synergistic binding of repressor to separate sites on DNA results in looping, with the intervening DNA as a topologically closed domain containing the two promoters. A closed DNA loop of 11 helical turns, which is in-flexible to torsional changes, disables the promoters either by resisting DNA unwinding needed for open complex formation or by impeding the processive DNA contacts by an RNA polymerase in flux during transcription initiation. Interaction between two proteins bound to different sites on DNA modulating the activity of the intervening segment toward other proteins by allostery may be a common mechanism of regulation in DNA-multiprotein complexes.
Related Concept Videos
RNA Polymerase II Accessory Proteins
Cooperative Binding of Transcription Regulators
The Eukaryotic Promoter Region
Bacterial Transcription
Transcription can be divided into three main stages, each involving distinct DNA sequences to guide the polymerase. These are:
Cooperative Binding of Transcription Regulators
The Eukaryotic Promoter Region

