Together with the initiator motif (Inr), another core promoter element, the DPE is recognized by the transcription factor II D (TFIID) subunits TAF6 and TAF9.[2][4][5] It has been shown that DPE-dependent basal transcription depends highly on the Inr (and vice versa) and on correct spacing between the two elements.[2][4][6]
The DPE consensus sequence was originally thought to be RGWCGTG,[2] however more recent studies have suggested it to be the similar but more general sequence RGWYV(T).[a][1][3][7] It is located about 28–33 nucleotides downstream of the transcription start site.[3]
Occurrence
It has been shown that the DPE is about as widely used as the TATA box in D. melanogaster.[6] While a DPE was found in many promoters that do not contain a TATA box, there are also promoters that contain both a TATA box and a DPE.[6]
The promoters of nearly all Hox genes of D. melanogaster, with the exception of the evolutionarily most recent genes, Ubx and Abd-A, contain a DPE motif and lack a TATA box.[8]Drosophila promoters containing the DPE sequence include Abd-B, Antp P2, bride of sevenless, brown, caudal, E74, E75, engrailed, Gsα, labial, nmMHC, ras2, singed, stellate, and white.[2] In organisms other than D. melanogaster, the promoter of the human and mouse IRF1 gene has been found to contain a DPE consensus sequence at the appropriate distance from the transcription start site. This promoter, too, does not contain a TATA box.