This active repressor can bind to a region near the promoter called an operator (yellow) and thus interfere with RNA polymerase binding to the promoter, effectively preventing transcription.

A typical footprinting experiment involves radioactive labeling of the DNA region of interest—usually a larger chunk of DNA suspected to contain one or more transcription factor binding sites.

"This surprising discovery points to a small but crucial feature of the transcription factors: their START domain," a lipid-binding region within the TFs, which the researchers liken to a foreman ...

This precise transcribing of genes is handled by proteins known as transcription factors, which bind to the regulatory DNA, thereby generating instructions for the coding region. A fly's body has ...