Formation of the open complex exposes the template strand to the catalytic center of the RNA polymerase II enzyme. This facilitates formation of the first phosphodiester bond, which marks transcription initiation. As a result of this, the TFIIB basal transcription factor dissociates from the initiation complex.
The open transcription initiation complex is unstable and can revert to the closed state. Initiation at this stage requires continued (d)ATP-hydrolysis by TFIIH. Dinucleotide transcripts are not stably associated with the transcription complex. Upon dissociation they form abortive products. The transcription complex is also sensitive to inhibition by small oligo-nucleotides.
Dinucleotides complementary to position -1 and +1 in the template can also direct first phosphodiester bond formation. This reaction is independent on the basal transcription factors TFIIE and TFIIH and does not involve open complex formation. This reaction is sensitive to inhibition by single-stranded oligonucleotides.
|GO Biological Process||transcription initiation from RNA polymerase II promoter (0006367)|
|8612591||Opening of an RNA polymerase II promoter occurs in two distinct steps and requires the basal transcription factors IIE and IIH.||EMBO J||1996|
|3667620||Abortive initiation by RNA polymerase II in vitro at the adenovirus 2 major late promoter.||J Biol Chem||1987|
|9405375||Three transitions in the RNA polymerase II transcription complex during initiation.||EMBO J||1998|
|7601352||Recycling of the general transcription factors during RNA polymerase II transcription.||Genes Dev||1995|
|11784853||Translocation after synthesis of a four-nucleotide RNA commits RNA polymerase II to promoter escape.||Mol Cell Biol||2002|