Increased coimmunoprecipitation (co-IP) of endogenous corepressor (Eto2, Sin3A, and Hdac2) with Pu.1 in Runx1-deficient cells. (A) Increased co-IP of endogenous corepressor with Pu.1 from PUER shRunx1 compared with PUER empty vector (control) cells. Input indicates nonimmunoprecipitated cell lysate; IgG, control IP with isotype antibody; C, PUER control; and shR, PUER shRunx1. Cells were lysed 4 hours after addition of OHT. (B) Runx1 protein expression is decreased in primary Runx1 haploinsufficient (Runx1^+/−) compared with wild-type littermate control (WT) bone marrow cells. Mice were genotyped as previously described.²⁸  (C) Co-IP of endogenous corepressor with endogenous Pu.1 from Runx1^+/− compared with WT bone marrow. Lysates were generated from freshly harvested bone marrow.