TATA box binding protein associated factor (TAF) histone-like fold (IPR004823) TATA box binding protein associated factor (TAF) is a component of the transcription initiation factor TFIID multimeric protein complex. TFIID plays a central role in mediating the promoter's response to a variety of activators and inhibitors. It interacts directly with TAFII-40 and binds securely to TAFII-250. It is a general transcription factor complex that binds to DNA. TFIID is essential for the initiation of DNA-dependent RNA polymerase II transcription. TFIID is the sole universal transcription initiation factor that binds to the TATA box. The initial step in the formation of a complex that can initiate transcription is the binding of TFIID to the TATA-box. The TATA box is characterized by a consistent sequence of TATA(A/T)A(A/T) (non-template chain sequence). It is primarily composed of A-T base pairs and is situated approximately -30bp (-25~-32bp) upstream of the transcription start site of most eukaryotic transcripts. It is one of the RNA polymerase's binding sites and determines the choice of gene transcription initiation. The transcription process can only commence once the RNA polymerase has established a strong bond with the TATA box.