The DNA-binding subunit of human transcription factor IID can interact with the TATA box as a multimer

Transcription initiation from eukaryotic protein-coding genes is a complex process that minimally requires RNA polymerase (pol) II (B) and at least seven general transcription factors. The 38-kDa subunit (TBP) of the human general transcription factor TFIID recognizes the TATA sequence element and initiates the assembly of the other general transcription factors and RNA pol II. It is believed, based on experiments with yeast recombinant protein, that TBP binds as a monomer to DNA. Using purified recombinant human TBP protein we find that TBP interacts with the TATA element as both a monomer and a dimer. The multimeric binding of TBP to DNA revealed by this study has important implications for the role of TBP in transcription initiation and suggests novel mechanisms whereby other transcription factors may interact with a RNA pol II preinitiation complex.