Figure 1.

mTORC1 Is Essential for Skeletal Development before and after Mesenchymal Condensation

(A–C) The whole and parts of skeleton of mutant embryos at E18.5. Embryos were double stained with alizarin red and Alcian blue (A). Scale bars, 5 mm (a and c) and 1 mm (e). Quantitative data of length of femur and tibia of (B) Prx1-Cre;Raptor^fl/fl embryos and (C) Col2a1-Cre;Raptor^fl/fl embryos at E18.5 (n = 4 independent samples).

(D–J) Histological analyses of the tibia at E18.5 (D). Scale bars, 500 μm (safranin O) or 100 μm (p-4EBP1). The whole and parts of skeleton of mutant embryos at (E) E16.5 and (F) E14.5. Embryos were double stained with alizarin red and Alcian blue. (E) Scale bars, 5 mm (a and c) and 1 mm (e). (F) Scale bars, 1 mm (a, c, and e). Quantitative data of length of femur and tibia of mutant embryos at (G and H) E16.5 and (I and J) E14.5 (n = 4 independent samples). Representative images of skeletal preparations and histological analyses derived from more than four embryos from different litters are shown.

^∗∗p < 0.01, significantly different from the value obtained in control embryos. Statistical significance was determined using the two-tailed, unpaired Student's t test. N.S., not significant.