Effects of GATA1 mutations on megakaryocytic maturation. (A) MGG and AChE staining of G1ME cells 72 hours after infection with wild-type or mutant GATA1-expressing vector. Scale bars, 20 μm. (B-C) Expression of (C) GATA1-activated and (D) GATA1-repressed genes in FACS-purified CD42-positive megakaryocytes as determined by RT-qPCR, normalized to β-actin and plotted as fold change from uninfected samples. (D-E) Average transcriptional activities (72 hours following transduction) of all examined activated (D, n = 10) and repressed (E, n = 6) genes. *P < .05. All error bars denote SEM (n = 3) unless otherwise noted. AChE, acetylcholinesterase.