Investigation of MKL1 domains needed for polyploidization. (A) Schematic of domain deletion constructs (empty vector [EV] not shown): full-length (FL) MKL1, ΔRPEL, ΔBasic, ΔSAP, ΔLZ, and ΔTAD. (B) Mean fluorescence intensity (MFI) of propidium iodide for Mkl1 knockout (KO) murine bone marrow-derived megakaryocytes transduced with each deletion construct (see Figure 2A), normalized to the EV value for each experiment. Individual experiments are indicated by data point colors (FL: P=0.007, n=6; ΔRPEL: P=0.037, n=4; ΔSAP: P=0.014, n=5). (C) MFI of propidium iodide for double knockout (dKO) murine bone marrow-derived megakaryocytes transduced with each deletion construct, normalized to the EV value for each trial. Individual trials are indicated by data point colors (FL: P=0.028, n=4; ΔRPEL: P=0.0004, n=4; ΔSAP: P=0.017, n=4). (D) Summary of data, showing mean fold-change in ploidy driven by each construct relative to EV.