What are enhancers and silencers in transcription?
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 are silencers and enhancers and what is their function?
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.
Is enhancer the same as activator?
Enhancers do not act on the promoter region itself, but are bound by activator proteins. These activator proteins interact with the mediator complex, which recruits polymerase II and the general transcription factors which then begin transcribing the genes.
How are enhancers activated?
Enhancers are activated after binding of activator proteins to their specific binding sites localised within the enhancers. Enhancers activate their targets (promoters) over variable distances. An enhancer can work on multiple promoters and a promoter can be activated by multiple enhancers.
How do activators and repressors work?
When an activator or inducer binds to an operon, the transcription process either increases in rate or is allowed to continue. When a repressor binds to an operon, the transcription process is slowed or halted.
What are enhancers and silencers and how do they influence whether or not a gene is transcribed?
Repressors decrease transcription. Groups of transcription factor binding sites called enhancers and silencers can turn a gene on/off in specific parts of the body. Transcription factors allow cells to perform logic operations and combine different sources of information to “decide” whether to express a gene.
Where do activators and repressors bind?
Activators bind to the enhancer regions in the DNA and facilitate the binding of RNA polymerase to the promoter. Repressors bind to the silencer regions and prevent the binding of RNA polymerase to the promoter.
How do repressors assist in regulation?
How do repressors assist in regulation? They block of slow down transcription. They can bind to an enhancer site or bind to an activator protein to block it.
What is the function of enhancer?
Enhancers are short regulatory elements of accessible DNA that help establish the transcriptional program of cells by increasing transcription of target genes. They are bound by transcription factors, co-regulators, and RNA polymerase II (RNAP II).
What is the role of an activator?
Activators are considered to have positive control over gene expression, as they function to promote gene transcription and, in some cases, are required for the transcription of genes to occur. Most activators are DNA-binding proteins that bind to enhancers or promoter-proximal elements.
How do activators and repressors affect transcription quizlet?
How do activators and repressors affect transcription? They regulate transcription. Activators increase transcription and repressors decrease it.