Inducer

Definition

An inducer is a molecule that initiates gene expression by inactivating a repressor, allowing transcription to proceed. Inducers play a crucial role in the regulation of operons, such as the lac operon in bacteria.

5 Must Know Facts For Your Next Test

1. Inducers bind to repressor proteins, causing them to change shape and release from the operator region of DNA.
2. In the lac operon, allolactose acts as an inducer by binding to the repressor and enabling transcription of genes involved in lactose metabolism.
3. Inducers can be naturally occurring molecules or synthetic compounds used in laboratory settings.
4. The presence of an inducer often signals that a substrate (e.g., lactose) is available and needs to be metabolized by specific enzymes.
5. Induction is a form of negative control where gene expression is turned on in response to an inducer molecule.

Review Questions

• What role does an inducer play in gene regulation?
• How does an inducer affect the repressor protein in an operon system?
• Give an example of a natural inducer and explain its function.

Related terms

Operon:

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

Repressor:

A protein that binds to the operator region of DNA and inhibits transcription.

Lac Operon:

A well-studied example of an inducible operon that controls the metabolism of lactose in bacteria.