Fetal Nfe2^−/− Mks fail to produce plasma membrane buds. (Ai) E14.5 Nfe2^+/+ (n = 8 mice) and Nfe2^−/− (n = 7 mice) circulating Plt counts. (Aii and Aiii) In situ Plt-forming morphologies in the E10.5 YS (ii, Nfe2^+/+, n = 7 mice; Nfe2^−/−, n = 8 mice) and E13.5 FL (iii, Nfe2^+/+, n = 4 mice; Nfe2^−/−, n = 4 mice). (B and C) Representative 3D z-projections of Mks in Nfe2^+/+ (B, n = 4 mice) and Nfe2^−/− (C, n = 4 mice) E13.5 FLs (CD41, gray). Scale bars, 100 µm. (D) Representative examples of Nfe2^−/− sessile, budding, and proPlt forming Mks in z-projection and optical section. Arrow indicates a membrane bud. Scale bars, 20 µm.