Fig. 2. SEM and marker analysis of limb bud development in ß-cat^Prx1/- embryos. A-B') Scanning electron microscopy (SEM) images of wild-type (WT, A,B) and ß-cat^Prx1/- (A',B') forelimbs at E9.5 (A,A') and E10.5 (B,B'). (C-E') Analysis of Fgf8 expression in somite staged embryos. Fgf8 expression (arrow) in a narrow stripe along the body wall at 17 somites in wild type (C) and ß-cat^Prx1/- (C'). Fgf8 expression domain at 20 somites in wild type (D) and ß-cat^Prx1/- (D'). Extensive Fgf8 expression in wild type (E) at 25 somites, which is reduced in ß-cat^Prx1/- forelimbs (arrows in E'). (F,F') At E10.5, Fgf8 expression in wild type becomes refined to the AER (F); a dashed expression domain is observed in ß-cat^Prx1/- forelimbs, corresponding to notches in the AER (F'). (G,G') At 19-20 somites, similar Fgf10 expression is seen in wild type (G) and ß-cat^Prx1/- (G') forelimbs. (H,H') At E10.75, Fgf10 expression in the distal mesenchyme is reduced in ß-cat^Prx1/- forelimbs (arrow, H') compared with wild type (H). (I-J') Tbx5 expression at 19-20 somites and at E10.75, comparing wild-type (I,J) and ß-cat^Prx1/- (I',J') forelimbs. Embryos are oriented anterior to the right.