Characterization of GATA-1 and GATA-2 binding sites in megakaryocytic cells. (A) Schematic of the model system used in this study, the murine erythromegakaryocytic progenitor cell line, G1ME. Gene expression profiles from GATA-2 knockdown conditions were previously published.21 (B) Flow cytometric plots showing the erythroid (Ter119) and megakaryocytic (CD42) characteristics of G1ME cells 72 hours after infection with GATA1 virus or GFP alone. (C) Distribution of GATA factor binding sites relative to genes. Gold and tan represent the average results of similar analyses performed on 10 randomly generated background BED files (expected) with identical chromosomal distribution and binding site size as the foreground sets (observed). P values from χ2 tests against the background control were all significant at P < .004. More significant values are as follows: *P < 10−10; **P < 10−50; and ***P < 10−100. (D) Venn diagram showing the intersection of GATA-1 binding sites in GATA-1–restored G1ME cells with the GATA-1 binding sites in estradiol-induced G1E-ER4 cells. A total of 40% of G1ME sites and 36% of G1E sites are bound in the opposite cell type. (E) Venn diagram showing the intersection of GATA-1–bound genes in GATA-1–restored G1ME cells with the GATA-1–bound genes in estradiol-induced G1E-ER4 cells. A total of 62% of G1ME occupied genes and 67% of G1E-ER4 occupied genes are bound in the opposite cell type.
