Tmod3^−/−embryos are defective in definitive erythropoiesis with reduced progenitors, impaired terminal differentiation, and enucleation. (A) BFU-E per fetal liver. (B) CFU-E per fetal liver. Values in both are means ± SD of at least 3 independent embryos. (C) Representative flow cytometry profiles of R1-R5 erythroblast populations labeled with CD71/Ter119 in fetal livers from Tmod3^+/+ mice at E14.5. The percentage of cells in each R population with respect to total PI-negative cells is indicated for a representative Tmod3^+/+ fetal liver. (D) Percentage of cells in each R population, normalized to the number of total viable fetal liver cells from each embryo (Tmod3^+/+, n = 6; Tmod3^+/−, n = 19; Tmod3^−/−, n = 8). (E) Representative CD71/FSC profile of Tmod3^+/+ Ter119^hi cells sorted into 3 populations (S1, S2, and S3) according to cell size. The percentage of cells in each S population with respect to total Ter119^hi cells is indicated for a representative Tmod3^+/+ fetal liver. (F) Percentage of cells in each S population, normalized to the number of total Ter119^hi fetal liver cells from each embryo. (G) Representative flow cytometry of enucleated cells in the S3 population of Tmod3^+/+ fetal livers, using Syto-16 for nuclei and SytoX for cell viability. The percentage of enucleated and nucleated cells with respect to total S3 cells is indicated for a representative Tmod3^+/+ fetal liver. (H) Percentages of enucleated cells in S1, S2, and S3 populations. All values are means ± SD with at least 3 replicates. *P < .05, **P < .005; ***P < .001 for Tmod3^−/− vs Tmod3^+/+.