Ad
related to: what are enhancers in transcription
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 ...
The transcription of enhancers generally preceded transcription of transcription factors which, in turn, generally preceded messenger RNA(mRNA) transcription of genes. Carullo et al. [ 13 ] examined one particular cell type, neurons (from primary neuron cultures).
Multiple enhancers can act in a coordinated fashion to regulate transcription of one gene. [7] A number of genome-wide sequencing projects have revealed that enhancers are often transcribed to long non-coding RNA (lncRNA) or enhancer RNA (eRNA), whose changes in levels frequently correlate with those of the target gene mRNA. [8]
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.
An inactive enhancer may be bound by an inactive transcription factor. Phosphorylation of the transcription factor may activate it and that activated transcription factor may then activate the enhancer to which it is bound (see small red star representing phosphorylation of a transcription factor bound to an enhancer in the illustration). [12]
Transcription initiation is regulated by cis-acting elements (enhancers, silencers, isolators) within the regulatory regions of the DNA, and sequence-specific trans-acting factors that act as activators or repressors. [1] Gene transcription can also be regulated post-initiation by targeting the movement of the elongating polymerase. [40]
Enhancers are bound by transcription activator proteins and transcriptional regulation is typically controlled by more than one activator. Enhanceosomes are formed in special cases when these activators cooperatively bind together along the enhancer sequence to create a distinct three-dimensional structure.
It is likely that CTCF helps to bridge the transcription factor-bound enhancers to transcription start site-proximal regulatory elements and to initiate transcription by interacting with Pol II, thus supporting a role of CTCF in facilitating contacts between transcription regulatory sequences.