Mitochondrial aggregation in close proximity to the nucleus facilitates murine erythroblast enucleation. (A) Confocal analysis of mitochondrial localization in orthochromatic erythroblasts (G3) treated with monastrol or ciliobrevin D (CBD) for 4 hours. Cells were stained with TOM20 (mitochondria, red) and DAPI (nucleus, blue; bar, 5 μm). Grayscale images are also shown. (B) Mitochondrial positioning relative to the nucleus was quantified by measuring mitochondrial localization plotted against nuclear size. R² values were calculated to test goodness of fit for correlation between maturation (nucleus size) and mitochondrial localization index. (C) Flow plots displaying proportion of enucleated erythroblasts (% of DRAQ5⁻ cells) 18 hours post-FACS sorting, treated with indicated compound vs dimethyl sulfoxide (DMSO) control (top). Quantification of enucleation and viability with indicated treatment (bottom). Mean ± standard error of the mean (n ≥ 3). **P < .01 by Student t test.