Book of Abstracts: Albany 2003
June 17-21 2003
The Effect of the Sequences Flanking the TATA Box on TBP/TATA Box Interaction
The TATA binding protein (TBP) is one of the most important proteins involved in transcriptional regulation in all eukariotes. TBP binds to an eight base-pair segment of DNA called TATA box (consensus T·A·T·A·A/T·A·A/T·A/T/G, 1). The recognition of TATA boxes by TBP involves indirect reading of the DNA sequence, which means recognition of the intrinsic structure of the DNA target or its deformation upon complex formation. Previous studies from our laboratory (2) revealed a significant effect of the flanking sequences on the dissociation kinetics of TBP/TATA box complex, even though they are not being directly contacted by TBP in the equilibrium complex on the TATA box. Moreover, we observed a differential effect of the sequences flanking the TATA box on the kinetic stability of the binding of TBP to its target sites, as a function of the TATA box identity.
We have now systematically extended these studies, using sequence motifs of known structural properties in the regions flanking the TATA box. The results showed that the effect of the flanking sequence is structural in nature, and can be attributed to the structural properties of both the TATA box, and those of the flanking sequences. Furthermore, we have done in vitro selection experiments to uncover the identity of the sequences flanking the TATA box, which confer on the TBP/TATA box complex maximum kinetic stability. The results of these experiments will be presented.