Human GTFs ChIP-exo
The human genome is pervasively transcribed, yet only a small fraction contains genes. Here we address whether abundant noncoding transcription arises from specific promoters, and detail the fate of initiation factors once RNA polymerase (Pol) II initiates transcription. Using ChIP-exo applied to TBP, TFIIB, and Pol II, we identify ~160,000 promoter/transcription initiation complexes across the human genome, of which <5% are associated with mRNA genes. Nearly all contain the four core promoter elements: BREu, TATA, BREd, and INR, and have canonically positioned initiation factors. When Pol II moves into a transcriptionally paused state, TBP and TFIIB remain at promoters but appear to stay engaged with Pol II, possibly through interactions that differ from the pre-initiated state. The comprehensive and high resolution genome-wide detection of the initiation machinery produces a consolidated view of transcription initiation events from yeast to humans at Pol II/III TATA-containing/TATA-less coding and noncoding genes.