Fig. 1. The DM sheet gives rise to derivatives that colonize both the dermis and the myotome. (A) Five hours after electroporation, GFP-expressing cells (green) are located in the epithelial DM sheet. (B,C) At E5, GFP-labeled cells are present in the desmin-positive myotome (red) intermingled among desmin+ fibers. Labeled cells are also present in the dermis. At this stage, the dermo-1 mRNA signal (blue reaction product) is predominantly expressed in the superficial domain of the young dermis close to the ectoderm, whereas GFP-expressing cells are widespread throughout the entire dermis. (C) High magnification of the insert in B. Note that the GFP-labeled cells in myotome and dermis are located at corresponding mediolateral regions, further substantiating the proposed coherent mode of DM development (Ben-Yair et al., 2003). D, dermis; DM, dermomyotome; M, myotome; NT, neural tube. Scale bar: 20 µm in A; 180 µm in B; 50 µm in C.