The transcription factor IIB (TFIIB) is an essential factor for transcription by RNA polymerase II. TFIIB has been shown to be required for selective binding of RNA polymerase II, TFIIF and TFIID-DNA complex, and for specifying the start site of transcription. Human TFIIB is a single, 35 kDa polypeptide, homologous to yeast factor, the product of the SUA7 gene.
