Loss of sf3b1 triggers a G0/G1 cell-cycle arrest in erythroid progenitors. (A-B) Graph quantifying gata1:eGFP⁺ cells in sf3b1-mutant and wild-type siblings at 24, 36, and 48 hpf. (A) Percentage of gata1:eGFP⁺ cells. (B) Absolute number of gata1:eGFP⁺ cells per embryos. (C) Representative flow cytometry plots for panels A and B. (D) Graph quantifying the percentage of gata1:eGFP⁺ erythrocytes in G0/G1, S, or G2/M phases of the cell cycle at 24 hpf. Representative flow cytometry histograms of erythrocyte DNA content as measured by DAPI fluorescence intensity on sf3b1 mutants and siblings. All experiments were done in biological triplicates. Statistical significance calculated by an ANOVA with a Bonferroni FDR multitesting correction. **P < .01, ***P < .001, ****P < .0001. FSC, forward scatter; n.s., not significant.