Inhibition of Pax2 Transcription Activation with a Small Molecule that Targets the DNA Binding Domain

Grimley E, et al., 12(3):724-734, ACS Chem Biol, 2017

The Pax gene family represents crucial embryonic developmental control genes that encode DNA binding transcription factors. In vertebrates, Pax2 plays a key role in the development of the kidney and the reproductive systems. Authors hypothesize that Pax2 could be an excellent target in the development of therapeutics for renal diseases. Described herein is the use of a homology model of the Pax2 paired domain and a structure based virtual screening to identify small molecules that can inhibit Pax2 transcription activation by targeting the Pax2 DNA binding domain. The EG1 was identified as a compound that can effectively block Pax2 activity and the DNA binding. Binding affinity and kinetics of EG1 interacting with the Pax2 paired domain were studied using Bio-Layer Interferometry (BLI) with a Pall ForteBio Octet RED system. Biotinylated Pax2 protein was immobilized on to Streptavidin Biosensor probes. Subsequently, sensor tips were incubated in various concentrations of EGI. The binding buffer contained PBS with 0.1% DMSO. kon, koff, and KD values were determined by global fitting of the binding curves. A steady-state analysis of the binding curves (Req. vs. Concentration) provided an affinity constant consistent with that obtained from on- and off-rates. Overall results of this study suggest that the targeting of tissue-specific developmental control genes has a significant potential to minimize off-target activity and to be more effective in treatments.

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