(in protein synthesis) The region of a DNA molecule that signals the start of transcription. In eukaryote genes, the promoter typically has a core promoter very near to the transcription start site, often containing the base sequence TATA (hence it is called the TATA box). Other promoter elements are located ‘upstream’ of the core promoter and start site. Proteins called transcription factors bind to the promoter and ensure that the enzyme responsible for transcription, RNA polymerase, also binds correctly to the promoter with respect to the coding region of the gene. In prokaryotes and viruses, several genes can share the same promoter in units called operons. Prokaryote promoters have their own characteristic base sequence, the Pribnow box.