Fig. 7. Shoulder girdle defects in ß-catenin loss- and gain-of mutants. (A-A'') Alcian Blue/Alizarin Red stained forelimbs from E18.5 wild-type (A), ß-cat^Prx1/- (A') and ß-cat^ex3Prx1/+ (A'') embryos (n=6), shown at different magnification. (B-C) In situ hybridisation for the chondrocyte marker Col2a1 on E12.5 wild-type (B) and ß-cat^Prx1/- (B') and E14.5 ß-cat^Prx1/- (C) forelimbs, showing partial loss of the scapula anlage (arrowhead in B') and the presence of a small element (black arrow) separated from the distal element by a zone of low Col2a1 expression (red arrows, C). (D-E) In situ hybridisation for the joint marker Gdf5 on E12.5 wild-type (D) and ß-cat^Prx1/- (D'), and E14.5 ß-cat^Prx1/- (E) forelimbs, showing that Gdf5 is still expressed (green arrows, D',E). (F-K'') Whole-mount in situ hybridisation for Hoxc6 (F-F''), Hoxa9 (G-G''), Hoxa10 (H-H''), Meis1 (I-I''), Pax1 (J-J'') and Emx2 (K-K'') on E10.5 embryos. ß-cat^Prx1/- embryos show downregulation of Pax1 (J') and Emx2 (K'; n=5). ß-cat^ex3Prx1/+ embryos show reduced Pax1 (J'') and expanded Emx2 expression (K''). Embryos are orientated anterior to the top, distal to the right. (L) Semi-quantitative RT-PCR from ß-cat ex3fl/ex3fl Adeno-Cre- and Adeno-GFP (control)-infected micromass cultures showing upregulation of Emx2 and no upregulation of Lmx1b 14 hours after infection.