Fig. 2. Phenotype of the C4st1^gt mutation at E19.5 of embryogenesis. (A) Gross morphology of wild-type (part i, +/+) and C4st1^gt/gt embryos (ii, part gt/gt). (B-H) Alcian blue/Alizarin Red skeletal stains. (B) Multiple skeletal abnormalities are evident in mutant embryos. (C) Higher magnification of hind limbs, showing the severely shortened and thickened iliac bone (i), femur (f) and tibia and fibula (ti). Arrowhead indicates Alcian Blue staining of cartilage. (D) Vertebrae in the mutant display misshapen dorsal arches (arrowhead). (E) Reduced size of scapula (double-headed while arrow) in mutant embryos. (F) Phalanges 2 and 3, and the talus bone (arrow) fail to ossify in mutant hindlimbs (m, metatarsal bones). (G) Lateral view and (H) dorsal view of skull, showing normal size of frontal (a), parietal (b), interparietal (c) and supraoccipital (d) bones in mutant embryos, but smaller maxilla (arrowhead), mandible (arrow) and nasal bones in mutant embryos.