After lactose is removed from the environment, the repressor can once again bind to the operator/promoter, quickly turning off expression of the operon, returning expression to basal levels.

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.

lad (lac repressor) which contains its own promoter and terminator sequences; lacP (promoter) which can simply be described as the RNA polymerase-binding site; and lacO (operator) which is the ...

The Methyl-CpG binding protein 2 (MeCP2) has long been considered a transcriptional repressor, given its penchant for binding ... immunoprecipitation experiments to see if MeCP2 binds to the promoter ...