Enhancers, enhancers – from their discovery to today’s universe of transcription enhancers

Abstract

Abstract Transcriptional enhancers are short (200–1500 base pairs) DNA segments that are able to dramatically boost transcription from the promoter of a target gene. Originally discovered in simian virus 40 (SV40), a small DNA virus, transcription enhancers were soon also found in immunoglobulin genes and other cellular genes as key determinants of cell-type-specific gene expression. Enhancers can exert their effect over long distances of thousands, even hundreds of thousands of base pairs, either from upstream, downstream, or from within a transcription unit. The number of enhancers in eukaryotic genomes correlates with the complexity of the organism; a typical mammalian gene is likely controlled by several enhancers to fine-tune its expression at different developmental stages, in different cell types and in response to different signaling cues. Here, I provide a personal account of how enhancers were discovered more than 30 years ago, and also address the amazing development of the field since then.