Definition:

The TFIID basal transcription factor complex plays a major role in the initiation of RNA polymerase II (Pol II)-dependent transcription. TFIID recognizes and binds promoters with or without a TATA box via its subunit TBP, a TATA-box-binding protein, and promotes assembly of the pre-initiation complex (PIC). The TFIID complex consists of TBP and TBP-associated factors (TAFs), including TAF1, TAF2, TAF3, TAF4, TAF5, TAF6, TAF7, TAF8, TAF9, TAF10, TAF11, TAF12 and TAF13. The TFIID complex structure can be divided into 3 modules TFIID-A, TFIID-B, and TFIID-C. TAF3 forms the TFIID-A module together with TAF5 and TBP. Required in complex with TBPL2 for the differentiation of myoblasts into myocytes. The TAF3-TBPL2 complex replaces TFIID at specific promoters at an early stage in the differentiation process.