Operator

Definition

An operator is a DNA sequence that acts as a regulatory element, controlling the transcription of adjacent genes. It is the binding site for repressor proteins which can inhibit gene expression by blocking RNA polymerase.

5 Must Know Facts For Your Next Test

1. Operators are typically found in prokaryotic organisms as part of operons.
2. The binding of a repressor to an operator prevents transcription of the downstream genes.
3. Lac operon in E. coli is a classic example where the operator regulates gene expression in response to lactose availability.
4. Mutations in the operator region can lead to constitutive expression or complete repression of the associated genes.
5. Operators work closely with promoters and repressors to finely tune gene expression based on environmental conditions.

Review Questions

• What role does an operator play in gene regulation?
• How does the binding of a repressor protein to an operator affect transcription?
• Can you describe how mutations in the operator sequence might impact gene expression?

Related terms

Promoter: A DNA sequence where RNA polymerase binds to initiate transcription.

Repressor: A protein that binds to an operator and inhibits the transcription of adjacent genes.

Operon: A cluster of genes under the control of a single promoter and regulated together, commonly found in prokaryotes.