TFIIH pol II promoter:TFIID:TFIIA:TFIIB:Pol II:TFIIF:TFIIE complex pol II closed pre-initiation complex Formation of the closed pre-initiation complex Authored: Reinberg, D, 2003-09-11 07:42:30 Edited: Joshi-Tope, G, 0000-00-00 00:00:00 Pubmed8946909 Reactome Database ID Release 43109639 Reactome, http://www.reactome.org ReactomeREACT_632 The binding of TFIIH completes the assembly of the preinitiation complex (PIC) for RNA Polymerase II transcription. Although RNA polymerase binds the TATA box on the promoter DNA, no initiation of transcription occurs until TFIIH is bound to the PIC. TFIIH is the only factor with known enzymatic activities.