Fig. 1. Contribution of Myf5-derived cells to different cell types of the paraxial mesoderm. (A-K) Expression of lacZ in E9.5 (A,B,E), E10.5 (C,D,F) and E15.5 (G-K) Rosa26lacZ embryos crossed either with myogenin-Cre (A,B,E) or with Myf5-Cre mice (C,D,F-K). lacZ staining (blue) reveals Myf5-derived cells in the sclerotome at E10.5 (F), in the rib cartilage (G,I), vertebrae (H) and skeletal muscles of the body wall (G) and of a limb (J). Arrows in G indicate the limited presence of Myf5-derived cells in the diaphragm of this embryo. Very few Myf5-derived cells are present in the neural tube and in the dorsal root ganglia (arrows in K). Arrowheads in K indicate lacZ-positive chondrocytes in a vertebra. Scale bars: 100 µm.