Tmod3^−/−mice are embryonic lethal with anemia. (A) Viability of Tmod3^−/− embryos. Timed matings of Tmod3^+/− intercrosses were performed and embryos were harvested at stages E13.5 up to E18.5. The percentages reflect the numbers of live Tmod3^−/− embryos with respect to all embryos harvested in litters at each gestational stage. (B) Gross morphology of Tmod3^+/+ and Tmod3^−/− embryos at E14.5. Scale bar, 1 mm. (C) Wright-Giemsa staining of peripheral blood cytospins from Tmod3^+/+ and Tmod3^−/− embryos at E14.5. Large primitive enucleated RBC (arrowhead); smaller definitive enucleated RBC (arrow). Note that sizes of enucleated cells from Tmod3^−/− embryos are variable and do not fall into clear size categories. Scale bar, 20 µm. (D) The percentage of enucleated RBCs in peripheral blood cytospins from Tmod3^+/+ and Tmod3^−/− embryos at E13.5, E14.5, and E15.5. At least 300 cells were counted for each sample. Values are means ± SD (n = 5 to 13). ***P < .001. (E) Gross morphology of representative fetal livers from Tmod3^+/+ and Tmod3^−/− embryos at E15.5. (F) Total number of fetal liver cells from Tmod3^+/+ (n = 7), Tmod3^+/− (n = 18), and Tmod3^−/− (n = 5) embryos at E14.5. Values are means ± SD. ***P < .001. (G) Hematoxylin and eosin staining of paraffin sections from Tmod3^+/+ and Tmod3^−/− fetal livers fixed in Bouin’s solution. Normal orthochromatic erythroblast nuclei in Tmod3^+/+ fetal liver (arrowheads). Abnormal multilobular orthochromatic erythroblast nuclei in Tmod3^−/− fetal liver (arrows). Scale bar, 10 µm (i-ii); 5 µm (iii-iv). Panels C and G were acquired with a Zeiss Axioskop microscope with AxioCam ICc3 color camera using a ×20 objective (N.A. 0.5) at a zoom of 2 (Gi-ii) or a ×100 oil-immersion objective (N.A. 1.3) at a zoom of 1 (C and Giii-iv).