Promoters/Overview
The registry has a large collection of Promoters available. We categorize promoters in two ways. First, most promoters are designed for a particular RNA polymerase (RNAP) holoenzyme, e.g E. coli RNAP bound to a particular σ factor (a σ factor is a protein that confers specificity on E. coli RNAP for particular promoter sequences), or the RNAP from the T7 bacteriophage. Second, promoters are categorized by the manner in which they are regulated. For example a promoter may be unregulated (constitutive), positively regulated (activatable) or negatively regulated (repressible). Regulated promoters allow you to "program" biological systems. For example, you can perform logic (e.g. "If protein X is present, promoter Y is off") or ensure that a particular gene is only expressed when a particular small molecule is present in the media.