Difference between Inducible and Constitutive Promoter

Inducible Promoter

It is a strong regulatory promoter that helps in the effective expression of the desired gene. The regulatory promoters are activated only when they receive a specific stimulus. Upon activation, they bind to the RNA polymerase and transcriptional factors. Thus, the transcription process is initiated.

Usually, chemical agents, temperature, mechanical injury and even light act as stimuli for the inducible promoter.

Constitutive Promoter

A constitutive promoter is seen active in a cell under all circumstances. It differs from the regulatory promoters which become activated on a stimulus. Thus, the constitutive promoters carry a continuous transcription process in the desired gene. These are not influenced by the transcriptional factors.

Difference between Inducible and Constitutive Promoter

Inducible Promoter

Constitutive Promoter

It is a regulated promoter that initiates transcription only when it receives a stimulus.

It is an unregulated promoter that continuously carries transcription in the desired gene.

Chemical agents, steroids, alcohol, temperature, mechanical injury, oxygen and light can act as stimuli.

It is active under all circumstances and does not need specific stimuli.

Also Refer: Gene Regulation

Frequently Asked Questions on Difference between Inducible and Constitutive Promoter

What is a promoter?

The promoter is a vital DNA sequence of a genome. Usually, proteins bind to this sequence to initiate transcription. It is seen upstream near the transcription initiation site. They can be approximately around 100 to 1000 bp (base pairs) long.

What are activators and enhancers in genetics?

Activators are a set of transcription factors that increase the rate of transcription. Most of them are DNA-binding proteins that cohere with enhancers. Enhancers are DNA sequences (50-1500 base pairs long) that amplify transcription along with activators. Thus, they both have a positive effect on gene expression.

What is an operon?

An operon is a functional unit of DNA where multiple genes come under the control of a single promoter. It is composed of three DNA components. Promoter, operator and structural genes are those basic DNA components. Usually, an operator is a segment to which a repressor adheres. Sometimes, the term promoter can also denote a combination of promoter and operator.

Also Read: Transcription of DNA and Central Dogma

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