Fig. 5.

TAK1 is required for normal skeletal development and joint morphogenesis. (A) Alcian blue and alizarin red staining of E18.5 wild-type, Tak1^Col2, and Tak1^Prx embryos. Black arrow (A11, A12) indicates deltoid tuberosity and fusion of the patella (A13, A14) and humerus (H), radius (R), and ulna (U) at the elbow (A7, A8, A15, A16). Red arrows (A7, A8, A15, A16) indicate fusion of humerus and radius. (A15, A16) Yellow arrows indicate lateral fusion of the humerus (H) and ulna (U). (B) H&E staining of E18.5 wild-type and Tak1^Prx embryos at the lateral humeroulnar joint (B1, B2), the femorpatellar joint (B3, B4), and the lateral aspect of the knee joint (B5, B6). (B7–B10) Alcian blue, hematoxylin, and orange G staining of carpals (C5, C6) and tarsals (C7, C8) at E18.5 in wild-type and Tak1^Prx embryos. (C) H&E staining of the humeroradial joint of wild-type (C1, C3, C5, C7), Tak1^Col2 (C2, C4), and Tak1^Prx (C6, C8) embryos at E14.5 (×20 magnification) and E18.5 (×10 magnification).