Transcription from a TATA-less promoter requires a multisubunit TFIID complex

In eukaryotes, the TATA box-binding protein (TBP) is responsible for nucleating assembly of the transcription initiation machinery. Here, we report that a TFIID complex containing TBP is essential for transcription even at a promoter that lacks a TATA box. Immunopurification of TFIID reveals that the active species in reconstituting TATA-less transcription is a multisubunit complex consisting of TBP and many TBP-associated factors (TAFs).