TFIIB (also known as GTF2B, TF2B and general transcription factor IIB) is a ubiquitously expressed transcription factor that plays a central role in the assembly of the transcription pre-initiation complex through direct recruitment of RNA polymerase II. The protein localizes to the nucleus where it forms a complex (the DAB complex) with transcription factors IID and IIA. TFIIB serves as a bridge between IID, the factor which initially recognizes the promoter sequence, and RNA polymerase II.
