Repressor

The presence of tryptophan directly affects the activity of the genes—tryptophan molecules bind to the tryptophan repressor (a transcription factor), changing the repressor's structure such that the repressor binds to the genes.

OR1 repression increases binding affinity to OR2 due to repressor-repressor interaction.

Simultaneously, a repressor molecule is sent to surrounding cells to prevent them from producing the red pigment.

DNA damage induces the SOS gene repressor LexA to undergo autoproteolytic activity.

Eventually, the lactase will digest all of the lactose, until there is none to bind to the repressor.

Gene expression can also be controlled by repressor proteins that attach to silencer regions of the DNA and prevent that region of the DNA code from being expressed.

Gene expression can be controlled through the action of repressor proteins that attach to silencer regions of the DNA.

Lactose is inhibiting the repressor, allowing the RNA polymerase to bind with the promoter, and express the genes, which synthesize lactase.

Operators main An operator is a segment of DNA to which a repressor binds.

Protein cl turned ON, with repressor bound to OR2 polymerase binding is increased and turn OFF OR1.

Simultaneously, the Shh signaling network is controlled by a negative feedback loop wherein the Gli transcription factors activate the enhanced transcription of a repressor (Ptc).

The N-terminal DNA binding domain (labeled) of the lac repressor binds its target DNA sequence (gold) in the major groove using a helix-turn-helix motif.

The repressor will then bind to the operator, stopping the manufacture of lactase.

The tryptophan repressor blocks the transcription and expression of the genes, thereby creating negative feedback regulation of the tryptophan synthesis process.

This autonegative regulation ensures a stable minimum concentration of the repressor molecule and, should SOS signals arise, allows for more efficient prophage induction.