Fig. 5. Expression patterns of Wnt and FGF target genes correlate with cell behaviors in mouse limb buds. (A-C) Expression of Axin2^lacZ/+ reporter, (D-F) BrdU labeling, (G-I) Sox9 immunostaining, (J-L) Nmyc in situ hybridization, (M) Sdc1 fluorescent immunostaining. Sections through E10.5 forelimb buds (A,D,G,J), through the level of the central metacarpal in E11.5 forelimb buds (B,E,H,K,M), through E11.5 hind limb buds (C,F,I,L). Note co-localization of proliferation (BrdU labeling, D-F) with the Axin2^lacZ/+ reporter (A-C) and Nmyc expression (J-L), whereas chondrogenic differentiation (Sox9 expression, G-I) is mutually exclusive with proliferation and reporter expression. Dorsal is upwards, distal is rightwards. Scale bars: 100 µm.