Figure 3.

Overview of some of the main transcriptional mechanisms. The core promoter, localised around the transcription start site (TSS), contains binding sites for the basal transcription machinery. Specialised core transcription factors located close to the TATA box induce and stabilise pre-initiation complex (PIC) formation. In some cases, the core transcription factors promote the binding of Pol II and the initiation of transcription. Activation of a distal enhancer brings it into proximity of the core promoter, triggering transcription or elongation to synthesise full length mRNA.