The coiled-coil domain of PML and C-terminal zinc finger of GATA-1 mediate the PML:GATA-1 interaction. (A) Structure of full-length and truncated GATA-1 fragments used in B. GATA-1–expressing plasmids were sequentially truncated to produce the GATA1-(84-413), GATA1-(233-413), GATA1-(286-413), or GATA1-(84-245) or mutated to produce GATA1-(ΔC-ZF) that specifically deleted the C-terminal zinc finger for subsequent analysis of the critical domains for the GATA1:PML4 interaction. (B) Co-IP assay of differentially truncated/mutated GATA-1 fragments and full-length PML4. All GATA-1 truncates/mutates without the C-terminal zinc finger lost the ability to interact with PML4, indicating that the C-terminal zinc finger is essential for interaction with PML4. (C) Structure of full-length and truncated PML4 fragments used in D. PML4-expressing plasmids were sequentially truncated from the N-terminal to produce the PML4-(Δ100), PML4-(Δ200), and PML4-(Δ400) that lost the first 100, 200, and 400 aa or the PML4-(1-400) that deleted the C-terminal domain. (D) Co-IP assay of different PML4 truncates and full-length GATA-1. Deletion of the N-terminal 400 aa, as in PML4-(Δ400), impairs GATA-1–interacting ability of PML4, while truncation of the first 100 or 200 aa, as in PML4-(Δ100) or PML4-(Δ200), shows nonaffected or even increased GATA-1 interaction, indicating that the coiled-coil domain located in the 200 to 400 aa of PML is indispensable for the interaction with GATA-1. (E) The structure of 2 chimeric molecules generated by fusing C-terminal domain of PML1 (621-882 aa) to full-length PML4 (produces the PML1+4L) or to the 1 to 620 aa of PML4 (produces the PML1+4S). (F) Co-IP assay of the interaction between GATA-1 and the chimeric molecules PML1+4L and PML1+4S, showing that C-terminal PML1 partially disrupts the PML4:GATA-1 interaction, whereas the 13 aa at C-terminal PML4 (621-633 aa) is important for maintaining the GATA-1 interaction.