(A) Western blot analysis of individually isolated ESC clones. antiWDR5 blotting reveals the total expression level of WDR5 in mock, FH-WDR5 wild type, and FH-WDR5 F266A mutant ESCs. The FH tag adds ∼8 kDa to WDR5, resulting in the observed shift, where as the F266A sees no shift because the construct is N-terminally shorter. Orange boxes are draw around clones that were isolated and used in the RIPiT experiments due to their near endogenous expression level. (B) FPLC analysis of the selected wild type and F266A FH-WDR5 clones. Each fraction was subjected to western blot analysis for HA (tagged protein), WDR5, Ash2L, and RbBP5. Orange boxes appear around the endogenous large molecular weight MLL complex, where the majority of the tagged FH-WDR5 constructs elute.