Operator

Definition

An operator is a DNA sequence that serves as a binding site for regulatory proteins to control gene expression. It is typically located between the promoter and the genes of an operon.

5 Must Know Facts For Your Next Test

1. Operators are involved in the regulation of gene expression by interacting with repressor or activator proteins.
2. In the lac operon, the operator binds to the Lac repressor protein, inhibiting transcription when lactose is absent.
3. Mutations in the operator region can lead to constitutive expression or permanent repression of genes.
4. The operator functions within an operon, which is a cluster of genes under the control of a single promoter and operator sequence.
5. Operators can be negatively regulated by repressors or positively regulated by activators.

Review Questions

• What role does the operator play in gene regulation?
• How does a mutation in the operator region affect gene expression?
• Can you describe how the lac operon utilizes its operator to regulate lactose metabolism?

Related terms

Promoter:

A DNA sequence where RNA polymerase binds to initiate transcription.

Repressor:

A protein that binds to an operator to inhibit transcription.

Operon:

A cluster of genes under the control of a single promoter and operator.