Fig. 2. The -53.3/-48 region drives Myf5-nlacZ expression mainly in cervical somites and the hindlimb bud. X-gal staining at E12, with a -53.3/-48 Myf5-nlacZ transgene (A), and at E11.0, with a -56.4/-48 Myf5-nlacZ transgene (B). Black arrows indicate X-gal staining in fore- and hind-limbs. ß-galactosidase-positive cells are detected in the brain in prosomeres p1 and p4 (white arrowheads). The embryo shown in B was sectioned at the level of the cervical somites (white line) and the corresponding transverse cryostat section is shown under phase contrast (C) or fluorescence (D), after immunoreaction with an antibody against muscle myosin heavy chain (red labelling) to show differentiated muscle cells in the myotome, the extent of which is indicated by white arrows. Black arrowhead in C indicates ß-galactosidase-positive neurones within the ventral neural tube (NT). DRG, dorsal root ganglia.