Fig. 7. Transgenic analysis of the role of the Tcf/Lef and Gli binding sites present in the epaxial enhancer of the Myf5 gene. (A-E) X-gal staining of whole-mount embryos at E9.5, with the following enhancer sequences upstream of the ß-globin promoter and the nlacZ reporter transgene: (A) the early epaxial enhancer (Ep), (B) the extended version of this enhancer (EpE), (C) the Ep enhancer with a 5' and 3' end deletion that removes the TBF4 and TBF5 Tcf/Lef binding sites (Ep), (D) the deleted Ep enhancer with the Gli site mutated (EpGm), and (E) the deleted Ep enhancer with the Gli and remaining non-consensus Tcf/Lef binding site mutated (EpGT/Lm). (F,H) Transverse sections of the embryo shown in A at two different levels in the interlimb region, showing extensive labelling of cells in the epithelial dermomyotome of somites. (G,I) Transverse sections of the embryo shown in B at two different levels in the interlimb region; labelled cells are restricted to the epaxial region of the dermomyotome, closest to the neural tube (NT). The number of somites (S) is indicated. (J) Schematic representation of the fragments of the epaxial enhancer used in the different transgenic constructs shown in A to I. EpE corresponds to the EpExt sequence and Ep to the 5 sequence presented in Fig. 6B. Red circles indicate the positions of the Tcf/Lef binding sites, the green rectangle indicates the position of the Gli binding site and the blue circle indicates the non-consensus Tcf/Lef binding site. White crosses indicate that the corresponding sites have been mutated.