Difference Between Enhancer and Promoter

Main Difference

The main difference between Enhancer and Promoter is that Enhancer is a short region of DNA that can bound by proteins (activators) to increase the possibility of transcription of a particular gene whereas promoter is a region of DNA that initiates transcription of a specific gene.

Enhancer vs. Promoter

The enhancer is a short region of DNA that can bound by proteins (activators) to increase the chance of transcription of a particular gene but the promoter is a section of DNA that initiates transcription of a particular gene. An enhancer is a sequence of DNA works to enhance transcription whereas promoter is a series of DNA that initiates transcription. An enhancer can upstream or downstream from the site where transcription is initiating while promoters are situated near the transcription start sites of genes, on the same strand and upstream on the DNA. An enhancer does not need to close to the gene of interest, but the promoter is close to the gene that is replicating. An enhancer binds with transcription factors, but a promoter binds with transcription factors and an RNA polymerase enzyme. Enhancers are supposed to be associated with diseases such as type 2 diabetes, colorectal cancer, and cardiovascular disease conversely Promoters are supposed to associate with diseases such as asthma and beta-thalassemia. Both enhancer and promoter help to regulate genetic transcription.

Comparison Chart

EnhancerPromoter
Enhances transcriptionInitiate transcription
Binds with
Transcription factorTranscription factor as well as an RNA polymerase enzyme
Location
Can upstream or downstream from the transcription initiation siteUpstream from the transcription initiation site
Distance
No need to close the transcription initiation siteNeed to close to the transcription initiation site
Role
Increase the level of transcriptionControl the transcription start
Importance
It is associated with diseases such as type 2 diabetes, cardiovascular disease, and colorectal cancerAssociate with diseases such as asthma and beta- thalassemia
Function
Increase the rate of transcriptionDetermines where transcription occur

What is an Enhancer?

An enhancer is a short piece of DNA that works to speed up the rate of genetic transcription. An enhancer is between 20 to 400 base pairs of DNA in size also called a cis-regulatory element. An enhancer can localize either upstream or downstream of a particular gene either on the same or a different location associated with the gene to transcribe. An enhancer does not need to close to the initiation site of transcription to function. Enhancers are present and function in both prokaryotic and eukaryotic cells. A transcription factor attaches to the enhancer to stimulate the transcription of the gene. Enhancers are present on introns and exons and can act on the genes of a different chromosome. Enhancers are thousands of bases away from a transcription initiation site. Enhancers speed up the rate of transcription by bringing transcription factors near to the promoter. Enhancers also regulate more than one gene regardless of their location comparative to the genes. The rivals of the enhancers are the silencers, which can bind to the transcription factors called suppressors. Enhancers are an important genetic element in development to enhance the activation of transcription in cells. Enhancers play a major role in human disease by increasing the risk of diseases such as type 2 diabetes, colorectal cancer, and cardiovascular disease.

Examples

  • HACNS1, which has a role in the evolution of the human thumb.
  • Proximal epiblast enhancer (PEE), which is important during the development of the vertebrate body.

What is a Promoter?

The promoter is a piece of DNA sequences that specify where transcription of DNA by RNA polymerase starts. Promoters are involved in initiating genetic transcription and determine which DNA strand will transcribe, in which direction the transcription will occur — the size of the promoter is100-1000 bp. Promoters are typically found upstream from the start of transcription at the 5’end where transcription starts. Promoters are in a 5’position near to the gene to transcribe. Promoters are present in both prokaryotic cells and eukaryotic cells. The promoters bind to RNA polymerase enzyme and transcription factor. The promoter initiates transcription process by interacting with RNA polymerase and transcription factors. The RNA polymerase enzyme softly binds to a DNA sequence and moves beside the strand until it meets a promoter. It then forms a close promoter complex with the promoter. The RNA polymerase then continues to unwind the DNA at the transcription starting site to form an open promoter complex and Transcription is initiating. Many eukaryotic cells are an important part of the promoter known as the TATA box, which can found from 25 to 35 bases upstream from the starting point of transcription. Variations in promoter may be associated with certain diseases such as beta-thalassemia and asthma.

Examples

  • PEG-3 Promoter
  • Human Telomerase Reverse Transcriptase (hTERT)

Key Differences

  1. An enhancer is a part of DNA that enhances genetic transcription conversely a promoter is a part of DNA which initiate or start gene transcription.
  2. An enhancer can upstream or downstream from the site where transcription is initiating whereas promoter is always upstream from the region where transcription is initiating.
  3. An enhancer binds with transcription factors; on the contrary, a promoter binds with transcription factors and an RNA polymerase enzyme.
  4. An enhancer does not need to close to the site where transcription is initiating while a promoter is close to the site where transcription is initiating.
  5. An enhancer works to increase transcription, but a promoter works to initiate the transcription process.
  6. Enhancers are supposed to associate with diseases such as type 2 diabetes, cardiovascular disease, and colorectal cancer on the flip side promoters are thought to associate with diseases such as asthma and beta-thalassemia
  7. Examples of enhancer include HACNS1 and PEE while examples of the promoter are the PEG-3 promoter and human telomerase reverse transcriptase.

Conclusion

Above this discussion, it concludes that Enhancer is a short region of DNA that can bound by proteins to increase the possibility of transcription of a particular gene whereas promoter is an area of DNA that initiates the transcription of a particular gene. Both enhancer and promoter play an important role to regulate genetic transcription.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White

View all posts by Janet White