Search results
Results from the WOW.Com Content Network
In genetics, an enhancer is a short (50–1500 bp) region of DNA that can be bound by proteins to increase the likelihood that transcription of a particular gene will occur. [1] [2] These proteins are usually referred to as transcription factors. Enhancers are cis-acting. They can be located up to 1 Mbp (1,000,000 bp) away from the gene ...
An enhancer localized in a DNA region distant from the promoter of a gene can have a very large effect on gene transcription, with some genes undergoing up to 100-fold increased transcription due to an activated enhancer. [10] Enhancers are regions of the genome that are major gene-regulatory elements.
Transcription factors can be divided in two main categories: activators and repressors. While activators can interact directly or indirectly with the core machinery of transcription through enhancer binding, repressors predominantly recruit co-repressor complexes leading to transcriptional repression by chromatin condensation of enhancer regions.
The active enhancer is transcribed on each strand of DNA in opposite directions by bound RNAP IIs. Mediator (a complex consisting of about 26 proteins in an interacting structure) communicates regulatory signals from the enhancer DNA-bound transcription factors to the promoter. NELF, in complex with DSIF and RNAP II, can pause transcription.
Enhancers and their associated transcription factors have a leading role in the regulation of gene expression. [65] Enhancers are genome regions that regulate genes. Enhancers control cell-type-specific gene expression programs, most often by looping through long distances to come in physical proximity with the promoters of their target genes. [66]
The activator contains a DNA binding domain that binds either to a DNA promoter site or a specific DNA regulatory sequence called an enhancer. [2] [3] Binding of the activator-coactivator complex increases the speed of transcription by recruiting general transcription machinery to the promoter, therefore increasing gene expression.
Several cell function specific transcription factors (there are about 1,600 transcription factors in a human cell [31]) generally bind to specific motifs on an enhancer [32] and a small combination of these enhancer-bound transcription factors, when brought close to a promoter by a DNA loop, govern the level of transcription of the target gene.
A transcriptional activator is a protein (transcription factor) that increases transcription of a gene or set of genes. [1] 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.