In
genetics, an
enhancer is a short (50-1500 bp) region of
DNA that can be bound with
proteins (
activators) to activate
transcription of a
gene. These proteins are usually referred to as
transcription factors. Enhancers are generally
cis-acting, located up to 1 Mbp (1,000,000 bp) away from the gene and can be upstream or downstream from the start site, and either in the forward or backward direction. There are hundreds of thousands of enhancers in the human genome.