Cloning and biochemical characterization of TAF-172, a human homolog of yeast Mot1.
The TATA binding protein (TBP) is a central component of the eukaryotic transcriptional machinery and is the target of positive and negative transcriptional regulators. Here we describe the cloning and biochemical characterization of an abundant human TBP-associated factor (TAF-172) which is homologous to the yeast Mot1 protein and a member of the larger Snf2/Swi2 family of DNA-targeted ATPases. Like Mot1, TAF-172 binds to the conserved core of TBP and uses the energy of ATP hydrolysis to dissociate TBP from DNA (ADI activity). Interestingly, ATP also causes TAF-172 to dissociate from TBP, which has not been previously observed with Mot1. Unlike Mot1, TAF-172 requires both TBP and DNA for maximal (approximately 100-fold) ATPase activation. TAF-172 inhibits TBP-driven RNA polymerase II and III transcription but does not appear to affect transcription driven by TBP-TAF complexes. As it does with Mot1, TFIIA reverses TAF-172-mediated repression of TBP. Together, these findings suggest that human TAF-172 is the functional homolog of yeast Mot1 and uses the energy of ATP hydrolysis to remove TBP (but apparently not TBP-TAF complexes) from DNA.
Pubmed ID: 9488487 RIS Download
Adenosine Triphosphatases | Adenosine Triphosphate | Amino Acid Sequence | Animals | Base Sequence | Cell Line | Cloning, Molecular | DNA Helicases | DNA, Complementary | DNA-Binding Proteins | Fungal Proteins | HeLa Cells | Humans | Molecular Sequence Data | Recombinant Fusion Proteins | Saccharomyces cerevisiae | Saccharomyces cerevisiae Proteins | Sequence Homology, Amino Acid | Spodoptera | TATA-Binding Protein Associated Factors | TATA-Box Binding Protein | Transcription Factor TFIID | Transcription Factors | Transcription, Genetic