Promoter

Definition

A promoter is a DNA sequence that initiates gene transcription by providing a binding site for RNA polymerase. It is essential for the regulation and expression of genes.

5 Must Know Facts For Your Next Test

1. Promoters are located upstream of the coding sequence of a gene.
2. The promoter region includes specific sequences like the TATA box in eukaryotes.
3. In prokaryotes, promoters often contain -10 and -35 consensus sequences recognized by sigma factors.
4. Promoter strength determines the frequency of transcription initiation.
5. Mutations in promoter regions can significantly affect gene expression levels.

Review Questions

• Where is the promoter located relative to the coding sequence of a gene?
• What specific sequences are commonly found within promoter regions in eukaryotes and prokaryotes?
• How can mutations within a promoter affect gene expression?

Related terms

RNA Polymerase:

An enzyme that binds to promoters and synthesizes RNA from a DNA template.

Operon:

A cluster of genes under the control of a single promoter, transcribed as a unit.

Sigma Factor: A protein needed for initiation of transcription in prokaryotes, facilitating RNA polymerase binding to promoters.