What is the difference between enhancers and silencers?
A cis-regulatory sequence that increases the activity of a gene when bound by transcription factors is called an enhancer, while a sequence that causes a decrease in gene activity is called a silencer.
What do enhancers and silencers do?
Enhancers function as a “turn on” switch in gene expression and will activate the promoter region of a particular gene while silencers act as the “turn off” switch. Though these two regulatory elements work against each other, both sequence types affect the promoter region in very similar ways.
What is a promoter vs enhancer?
An enhancer is a sequence of DNA that functions to enhance transcription. A promoter is a sequence of DNA that initiates the process of transcription. A promoter has to be close to the gene that is being transcribed while an enhancer does not need to be close to the gene of interest.
What are silencers in transcription?
Silencers are regulatory DNA elements that reduce transcription from their target promoters; they are the repressive counterparts of enhancers. Although discovered decades ago, and despite evidence of their importance in development and disease, silencers have been much less studied than enhancers.
Do activators bind to promoters?
Most activators are DNA-binding proteins that bind to enhancers or promoter-proximal elements. The DNA site bound by the activator is referred to as an “activator-binding site”.
How does enhancer stimulate transcription?
Enhancer sequences are regulatory DNA sequences that, when bound by specific proteins called transcription factors, enhance the transcription of an associated gene. Because DNA is folded and coiled in the nucleus, the enhancer may actually be located near the transcription start site in the folded state.
How do you detect enhancers?
Gene reporter assays in cultured cells is generally employed to identify if a selected sequence can act as an enhancer, but in vivo testing of the reporter or in vivo editing of the enhancer in transgenic animals are considered the definitive proof [37].