Impairment of erythroid differentiation by GATA1 mutations. (A) Space-filling model of the GATA1 NF from PDB code 1Y0J with DNA-binding residues in red (based on PDB code 1GAT), FOG1-binding residues in cyan, and LMO2-interacting residues in blue. The locations of disease-associated mutations are noted. The middle structure has been rotated 120 degrees around a horizontal axis from the leftmost model, and the rightmost structure is rotated a further 80 degrees. (B) MGG and benzidine staining of G1E cells expressing wild-type or mutant GATA1 after 72 hours of E2 treatment. The percentage of hemoglobin-positive cells is indicated in the upper right corner of each benzidine panel. Scale bars, 20 μm (left panels) and 50 μm (right panels). (C-D) Expression of (C) GATA1-activated and (D) GATA1-repressed genes after 24 hours of E2 treatment as determined by RT-qPCR, normalized to β-actin and plotted as fold change from uninfected samples. (E-F) Average transcriptional profiles after 24 hours of E2 treatment of all activated (E, n = 24) and repressed (F, n = 6) genes examined. Note that the reduction in transcriptional repression by R216Q and D218G is not statistically significant. *P < .05. All error bars denote SEM (n = 3) unless otherwise noted. MGG, May-Grünwald-Giemsa; PDB, Protein Data Bank.