WDR5 Differential Scanning Fluorimetry (DSF) Assay. The compound was dissolved in DMSO at a concentration of 10 mM before mixing with WDR5. 2 µM full-length WDR5 protein was mixed with 5x SYPRO Orange (Thermo Fisher Scientific, S6650) in DSF assay buffer (20 mM HEPES pH = 8.0, 150 mM NaCl) and then mixed with 200 µM compound in a 384-well PCR plate. The mixture solution was then incubated with shaking for 5 min before running the thermal melting experiments on the CFX384 Touch™ Real-Time PCR detection system (Bio-Rad). The samples were heated from 20 to 95 °C at a rate of 0.5 °C/30 s. The melting curve and peak data was analyzed by a modified Boltzmann equation using a Novartis in-house program. The reported Tm (melting temperature) values are based on the mean values from two independent experiments in triplicates.