Deletions from the cytoplasmic domain of Mpl.

(A) Schematic representation of the full-length c-mpl(flmpl) and 2 deletion mutants (Δ3mpl, Δ34mpl). The intracellular domain of flmpl contains 121 amino acids, including conserved box1 and box2 motifs (black area) and 5 tyrosine residues. Deleted regions are shown in gray. TM, transmembrane domain. The flmpl and the mutants have the Flag epitope tag sequence at the N-terminus. (B) Flow cytometry analysis of the expression of Flag-Mpl or Flag-mutants in undifferentiated ES cells and during their differentiation. Cells were stained with the M1 anti-Flag antibody (gray peak) or isotype control antibody (open peak). Second-step antibody was FITC-conjugated goat F(ab′)2 antimouse immunoglobulins.