What is the Difference Between Inducible and Constitutive Promoter?

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The main difference between inducible and constitutive promoters lies in their regulation and activity. Here is a comparison of the two types of promoters:

Inducible Promoter:

  • Regulated promoter that initiates transcription only when it receives a stimulus.
  • Activated by various stimuli, such as chemical agents, temperature, mechanical injury, and light.
  • Examples include promoters activated by heat shock, chemical compounds, or specific hormones.
  • Used for dynamic studies of gene expression in vivo, timed expression of tagged protein fusions, and depletion assays.

Constitutive Promoter:

  • Unregulated promoter that continuously carries transcription in the desired gene.
  • Active under all circumstances and does not need specific stimuli.
  • Continuous transcription process within the target gene, not affected by transcription factors.
  • Wide range of applications, from expressing selective marker genes to consistent overexpression of proteins.

In summary, inducible promoters are regulated and initiate transcription only in response to specific stimuli, while constitutive promoters are unregulated and continuously transcribe the associated genes regardless of the prevailing circumstances.

Comparative Table: Inducible vs Constitutive Promoter

Inducible and constitutive promoters are two different types of promoters that regulate the transcription of genes. Here is a table comparing their characteristics:

Feature Inducible Promoter Constitutive Promoter
Definition A regulated promoter that initiates transcription only when it receives a stimulus. An unregulated promoter that continuously carries transcription in the desired gene without needing specific stimuli.
Stimuli Activated by specific stimuli such as chemical agents, temperature, mechanical injury, or light. Active under all circumstances and does not need specific stimuli.
Transcription Initiates transcription only when activated by a stimulus, binding to RNA polymerase and transcriptional factors. Continuous transcription process in the desired gene, not influenced by transcriptional factors.
Examples Examples include opine promoter and CaMV 35S promoter. Examples include plant ubiquitin promoter, rice actin 1 promoter, and maize alcohol dehydrogenase promoter.

Inducible promoters are useful for studying gene expression in vivo, timed expression of tagged protein fusions, and depletion assays. Constitutive promoters, on the other hand, are used for the expression of transgenes and have a wide range of applications, from expressing selective marker genes to consistent overexpression of proteins.