Modulation of FOXO3 and TP53 expression in p21^−/−/Hbb^th3/+ erythroid cells. (Ai) FOXO3 nuclear localization in erythroid progenitors from WT, p21^−/−, Hbb^th3/+, and p21^−/−/Hbb^th3/+ mice using confocal microscopy; analyses of at least 40 cells (quantification, right graph). Scale bar: 5 μm. (Aii) TP53 nuclear localization in erythroid progenitors from WT, p21^−/−, Hbb^th3/+, and p21^−/−/Hbb^th3/+ mice using confocal microscopy; analyses of at least 40 cells (quantification, right graph). Scale bar: 5 μm. (B) Histograms of Mitotracker Green staining of TER119⁺ cells in different gates (left) and quantification (right). (C) Mitochondrial morphology in erythroid progenitors from WT, p21^−/−, Hbb^th3/+, and p21^−/−/Hbb^th3/+ mice using confocal microscopy; analyses of at least 30 cells. Scale bar: 5 μm. Quantification of mitochondrial area (top). Results are shown as mean ± standard error of the mean; ∗P < .05; ∗∗P < .01; ∗∗∗P < .001; ∗∗∗∗P < .0001; and n.s., not significant.