GATA1 colocalizes with partner proteins in L8057 cells and primary megakaryocytes. Degree of colocalization (shown on the y-axis) is revealed by antibody blocking in L8057 (A) and primary megakaryocyte nuclei (B). αFOG1, -GFI1B, -ETO2, and -ZFP143 antibodies, but not αSC35 antibody, block access to αGATA1 antibody (A,B). Conversely, αGATA1 antibody blocks access of αFOG1, -GFI1B, -ETO2, and -ZFP143 antibodies, to their respective epitopes (B).