Figure 3

Col11a1a expression was required for Meckel’s chondrocyte organization, extension, and mineralization. The Fli1a:EGFP expressing cells in the Meckel’s cartilage formed an organized stack of chondrocytes that allowed the arch-like structure of Meckel’s cartilage to form (A) Alizarin Red staining indicated that the perichondraal cells produced a mineralized structure immediately adjacent to the Meckel’s cartilage ((C), white asterisk) and initiated mineralization at the central distal tip (B,C). In contrast, the cells of the morphant were not flattened, nor were they organized into a stack of cells as observed in the control ((D) compared to (A)). Lateral mineralization of the bilateral rods in the morphant was not detected ((F), white asterisk). Mineralization was detected by Alizarin Red staining at the central distal tip (F). Scale bars 20 μm.