TATA Binding Protein Associated Factor 172 (BTAF1)

Initiation of transcription by RNA polymerase II requires the assistance of TATA box-binding protein (TBP) and TBP-associated factors, or TAFs, in 2 distinct complexes, TFIID and B-TFIID. The TFIID complex is composed of TBP and more than 8 TAFs. However, the majority of TBP is present in the B-TFIID complex, which is composed of TBP and TAFII170, also called TAF172, and has DNA-dependent ATPase activity.Cofractionation and coprecipitation experiments showed that the protein encoded by the TAFII170 cDNA is the TAF subunit of B-TFIID. Sequence analysis predicted that the 1,849-amino acid TAFII170 protein harbors the 7 motifs characteristic for proteins with ATPase activity. The ATPase region of TAFII170 shares 62% amino acid identity with yeast Mot1.