#1
| |||
| |||
![]() |
#3
| |||
| |||
![]()
The downstream core element is a transcription core promoter sequence that is within the transcribed portion of a gene. The consensus sequence for the DCE is CTTC...CTGT...AGC. These three consensus elements are referred to as subelements: "SI is CTTC, SII is CTGT, and SIII is AGC." A core promoter that contains all three sub elements may be much less common than one containing only one or two. The differences between core promoters with downstream elements may be explained by "TATA- and DPE-dependent promoters are specific for particular enhancers", "preferences of activators for specific core promoter architectures", and "the presence of a DCE or [downstream core promoter element (DPE)] might be indicative of an architecture designed for specific regulatory networks, such as the regulation of housekeeping promoters versus tissue-specific promoters (or other highly regulated promoters) or the regulation of subsets of viral promoters." DCE SIII can function independently of SI and SII. Transcription factor II D (TFIID), a transcription factor that is part of the RNA polymerase II holoenzyme, interacts with promoters containing only SIII of the DCE suggesting a critical spacing parameter between SIII and the TATA box, initiator element, or some combination of the two. TFIID probably serves as a core promoter recognition complex. TAF1 interacts with the DCE in a sequence-dependent manner. |