[Show abstract][Hide abstract] ABSTRACT: Despite their enormous potential as novel research tools and therapeutic agents, artificial transcription factors (ATFs) that
up-regulate transcription robustly in vivo remain elusive. In investigating an ATF that does function exceptionally well in vivo, we uncovered an unexpected relationship between transcription function and a binding interaction between the activation
domain and an adjacent region of the DNA binding domain. Disruption of this interaction leads to complete loss of function
in vivo, even though the activation domain is still able to bind to its target in the transcriptional machinery. We propose that
this interaction parallels those between natural activation domains and their regulatory proteins, concealing the activation
domain from solvent and the cellular milieu until it binds to its transcriptional machinery target. Inclusion of this property
in the future design of ATFs should enhance their efficacy in vivo.
[Show abstract][Hide abstract] ABSTRACT: Programmable DNA-binding polyamides coupled to short peptides have led to the creation of synthetic artificial transcription factors. A hairpin polyamide-YPWM tetrapeptide conjugate facilitates the binding of a natural transcription factor Exd to an adjacent DNA site. Such small molecules function as protein-DNA dimerizers that stabilize complexes at composite DNA binding sites. Here we investigate the role of the linker that connects the polyamide to the peptide. We find that a substantial degree of variability in the linker length is tolerated at lower temperatures. At physiological temperatures, the longest linker tested confers a "switch"-like property on the protein-DNA dimerizer, in that it abolishes the ability of the YPWM moiety to recruit the natural transcription factor to DNA. These observations provide design principles for future artificial transcription factors that can be externally regulated and can function in concert with the cellular regulatory circuitry.
Preview · Article · May 2005 · Proceedings of the National Academy of Sciences