Promoter

Promoter is a region of DNA that initiates transcription of a particular gene. Promoters are located near the transcription start sites of genes, on the same strand and upstream on the DNA (towards the 5' region of the sense strand). Promoters can be about 100–1000 base pairs long.

Structure

Promoters contain specific DNA sequences that provide a secure initial binding site for RNA polymerase and for proteins called transcription factors that recruit RNA polymerase. These transcription factors have specific activator or repressor sequences of corresponding nucleotides that attach to specific areas of the promoter region and upstream promoter element (UPE).

Function

In bacteria, the promoter provides a binding site for the RNA polymerase. In both bacteria and eukaryotes, the promoter functions as a regulatory sequence that enables a gene to be transcribed.

Types of Promoters

Promoters can be classified into two types based on their association with the gene that they regulate.

• Proximal Promoters are the ones located very close to the gene they regulate.
• Distal Promoters are the ones located far away from the gene they regulate.

See also

• Gene expression
• Operon
• Regulation of gene expression
• Transcription (genetics)