Information About

Enhancer




An enhancer does not need to bind close to the Transcription initiation site to affect its transcription, as some have been found to bind several hundred thousand Base Pairs upstream or downstream of the start site. Enhancers can also be found within Intron s. An enhancer's orientation may even be reversed without affecting its function. Furthermore, an enhancer may be excised and inserted elsewhere in the chromosome, and still affect gene transcription.That is the reason that intron polymorphisms are checked though they are not transcribed and translated.

Currently, there are two different theories on the information processing that occurs on enhancers:
  • Enhanceosomes - rely on highly cooperative, coordinated action and can be disabled by single point mutations that move or remove the binding sites of individual proteins

  • Flexible billboards - less integrative, multiple proteins independently regulate gene expression and their sum is read in by the basal transcriptional machinery



REFERENCES

  • Arnosti, David N. and Kulkarni, Meghana M. (2005). Transcriptional enhancers: intelligent enhanceosomes or flexible billboards? ''Journal of Cellular Biochemistry'' 94 890–898.