gene regulatory element enhancer a set of short sequence elements which stimulate transcription of a gene and whose function is not critically dependent on their precise position or orientation. An enhancer is a short region of DNA that can be bound with proteins (namely, the trans-acting factors, much like a set of transcription factors) to enhance transcription levels of genes (hence the name) in a gene cluster. While enhancers are usually cis-acting, an enhancer does not need to be particularly close to the genes it acts on, and sometimes need not be located on the same chromosome. (http://en.wikipedia.org/wiki/Enhancer_(genetics))