The TBP-like factor: an alternative transcription factor in Metazoa?

Protein sequence analysis has revealed a family of TATA-binding-protein (TB P)-like factors (TLFs) in metazoan organisms. Modelling of the three-dimens ional structure of these TLFs suggests that they form an asymmetric saddle- like structure and that, unlike TBP, TLFs might bind to DNA sequences other than classical TATA boxes. Thus, the existence of TLFs presents a challeng e to the doctrine that TBP is a universal regulator of transcription in met azoans.