Definition

Noun: A gene that controls the activity of one or more adjacent structural genes by regulating the production of messenger RNA (mRNA). It is a component of an operon, a genetic regulatory system.

Usage

The term "operator gene" is used in molecular biology and genetics to describe a specific regulatory DNA sequence. It does not code for a protein itself but serves as a binding site for a repressor protein, which can block transcription. When the repressor is not bound, RNA polymerase can transcribe the adjacent structural genes into mRNA.

Examples

• In the classic operon model, the operator gene is the site where the lac repressor protein binds to inhibit transcription of the genes for lactose metabolism.
• A mutation in the operator gene can prevent repressor binding, leading to the constitutive (constant) expression of the structural genes.
• The operator gene works in conjunction with a promoter gene to control the rate of transcription for a cluster of functionally related genes.

Advanced Usage

• Constitutive operator mutant: An operator gene with a mutation that prevents repressor binding, resulting in continuous transcription of the operon's genes.
• Cis-dominant effect: A mutation in an operator gene typically affects only the structural genes on the same DNA molecule (in ), not those on a separate chromosome.

Variants and Related Words

• Operon: A unit of genetic function consisting of a promoter, operator, and one or more structural genes.
• Regulatory gene: A gene (often elsewhere on the chromosome) that codes for a repressor or activator protein that interacts with the operator.
• Structural gene: A gene that codes for any RNA or protein product other than a regulatory factor (e.g., an enzyme).

Synonyms

• Operator (in the context of an operon)
• Operator sequence
• Regulatory element (specific type)

Related Phrases / Concepts

• Operator-repressor interaction: The binding event between the repressor protein and the operator DNA sequence that regulates gene expression.
• Negative control: A regulatory system where a repressor protein bound to the operator gene turns transcription . The operon is an example of negative control.

Noun

1. a gene that activates the production of messenger RNA by adjacent structural genes