Transcription Factor II D
D) is one of several general transcription factors
that make up the RNA polymerase II preinitiation complex
D is itself composed of several subunits
called TBP-associated factors (TAFs, of which there are 14) and the TATA Binding Protein
In a test tube, only TBP is necessary for transcription at promoters that contain a TATA box. TAFs, however, add promoter selectivity, especially if there is no TATA box sequence for TBP to bind to.
Subunits in the TFIID complex include: