DNA sequence that binds activators to increase the likelihood of gene transcription
Seen here is a four step diagram depicting the usage of an enhancer. Within this DNA sequence, protein(s) known as transcription factor(s) bind to the enhancer and increase the activity of the promoter.
DNA
Enhancer
Promoter
Gene
Transcription Activator Protein
Mediator Protein
RNA Polymerase
In genetics, an enhancer is a short (50–1500 bp) region of DNA that can be bound by proteins (activators) 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, upstream or downstream from the start site.[2][3] There are hundreds of thousands of enhancers in the human genome.[2] They are found in both prokaryotes and eukaryotes.[4] Active enhancers typically get transcribed as enhancer or regulatory non-coding RNA, whose expression levels correlate with mRNA levels of target genes.[5]
The first discovery of a eukaryotic enhancer was in the immunoglobulin heavy chain gene in 1983.[6][7][8] This enhancer, located in the large intron, provided an explanation for the transcriptional activation of rearranged Vh gene promoters while unrearranged Vh promoters remained inactive.[9] Lately, enhancers have been shown to be involved in certain medical conditions, for example, myelosuppression.[10] Since 2022, scientists have used artificial intelligence to design synthetic enhancers and applied them in animal systems, first in a cell line,[11] and one year later also in vivo.[12][13]
^Banerji J, Olson L, Schaffner W (July 1983). "A lymphocyte-specific cellular enhancer is located downstream of the joining region in immunoglobulin heavy chain genes". Cell. 33 (3): 729–740. doi:10.1016/0092-8674(83)90015-6. PMID6409418. S2CID23981549.
^Gillies SD, Morrison SL, Oi VT, Tonegawa S (July 1983). "A tissue-specific transcription enhancer element is located in the major intron of a rearranged immunoglobulin heavy chain gene". Cell. 33 (3): 717–728. doi:10.1016/0092-8674(83)90014-4. PMID6409417. S2CID40313833.
^de Almeida BP, Reiter F, Pagani M, Stark A (May 2022). "DeepSTARR predicts enhancer activity from DNA sequence and enables the de novo design of synthetic enhancers". Nature Genetics. 54 (5): 613–624. doi:10.1038/s41588-022-01048-5. PMID35551305.