[1] In bacteria and eukaryotes, proteins TFIIB and sigma factor are involved in the initiation of transcription, where they facilitate preinitiation complex formation and specific RNA Polymerase-DNA binding.

[3] In respect to its eukaryotic equivalent, TFB shows "high levels of structural and functional conservation.

[3] Crosslinking experiments have shown this domain is located close to the transcription start site.

[7] TFB is recruited by another translation factor, TBP, after it recognizes the TATA box and bends the DNA so transcription can initiate.

TFB stabilizes the TBP-DNA complex so that the proteins can recruit RNA Polymerase and melt the DNA via a yet-unknown mechanism.