Fig. 1. A 560 bp fragment of the Msx2 promoter is sufficient for BMP responsiveness in 10T1/2 cells and murine embryonic limbs. (A) Genomic map showing fragments of murine Msx2 5' flanking sequence used in transgenic and transfection experiments. (B) Results of transient transfections of 10T1/2 cells with Msx2 promoter-TK-luciferase vectors bearing either the 1.8 kb or 560 bp fragment. (C-F) Comparisons of endogenous Msx2 expression by whole-mount in situ hybridization (C,F) and Msx2 promoter-hsplacZ transgene expression (D,E). (G) Limbs derived from E11.5 560bpMsx2-hsplacZ transgenic embryos implanted with Affigel agarose beads soaked in BMP4, TGFß1 or BSA. Limbs were stained for ß-galactosidase activity for the indicated times. Anterior towards the right. The beads are light blue; a positive response to ligand produces dark-blue staining around the bead.