InterPro

In eukaryotes, transcription initiation by polymerase II is modulated by both general and specific transcription factors. The general factors (which include TFIIA, TFIIB, TFIID, TFIIE, TFIIF, TFIIG and TFIIH) operate through common promoter elements, such as the TATA box. Transcription factor IIB (TFIIB) is of central importance in transcription of class II genes. It associates with TFIID-TFIIA bound to DNA (the DA complex) to form a ternary TFIID-IIA-IBB (DAB) complex, which is recognised by RNA polymerase II [PMID: 1876184, PMID: 1949150]. TFIIB comprises ~315-340 residues and contains an imperfect C-terminal repeat of a 75-residue domain that may contribute to the symmetry of the folded protein.

Proteins in this entry also include transcription factor IIIB subunit Brf1, which shares protein sequence similarity with TFIIB. In budding yeast, Brf1 interacts with several initiation-specific subunits of the pol III machinery, TBP, beta", TFC4p and the pol III subunits C34 and C17 [PMID: 11433012].