A common organization of sequences for the promoter of a eukaryotic structural gene

The core promoter is made up of a TATA box and a transcriptional start site. The TATA box sequence is 5?–TATAAAA–3?. The sequence of the transcriptional start site in the 5? to 3? direction is two pyrimidines (C or T), then CA, then five pyrimidines. The A marks the site of the first A in the RNA transcript. The sequences shown for the TATA box and transcriptional start site are those found in the coding strand. Py refers to pyrimidine, cytosine, or thymine. Regulatory elements, such as enhancers and silencers, are usually found upstream from the core promoter.