Repressor: meaning, definitions and examples

genetics

A repressor is a DNA- or RNA-binding protein that inhibits the expression of one or more genes by binding to the operator or associated silencer region.

blocker, inhibitor, suppressor

Examples of usage

• The lac repressor binds to the operator in the absence of lactose.

• When the repressor is bound to the operator, RNA polymerase is blocked from transcribing the genes.

• The trp repressor prevents the transcription of the tryptophan biosynthesis genes.

• The binding of the repressor to the operator is sensitive to the concentration of the specific metabolite.

• In the presence of the inducer, the repressor undergoes a conformational change and releases the operator.