The genetics of TBP and TBP-related factors

The TATA-binding protein (TBP) has been considered a universal transcription factor that is required for initiation by all three nuclear RNA polymerases. The discovery of TBP-related factors in many metazoan organisms and a mammalian complex that can mediate RNA polymerase II transcription independently of TBP in vitro suggest that TBP might not have such a universal role as previously imagined. Recent genetic and functional analyses reveal that TBP and the TBP-related factors have specific and distinct functions in vivo.