(Downloading may take up to 30 seconds.
If the slide opens in your browser, select File -> Save As to save it.)
Click on image to view larger version.

Fig. 6. Wnt signaling regulates Sp8 expression. (A) Implantation of a
control cell pellet had no effect on Sp8 expression in the chick limb
bud. (B) Implantation of a Wnt3a-expressing cell pellet induced
Sp8 expression in the ectoderm (arrowheads). Asterisks indicate
pellets. (C) Injection of RCAS dominant-active ß-catenin induced
Sp8 expression in the wide region of ectoderm. (D) Electron
microscopic analysis of RCAS dominant-active ß-catenin-injected limb.
ß-Catenin activity induced ectopic ridge-like spikes. The inset in D is a
closer view of the ectoderm. (E,F) Sp8 expression in the forelimb bud
in wild-type (E) and Lrp6/ (F) embryos at
E10.5. The Sp8 expression domain in E and F are labeled with black
and red arrowheads, respectively. (G,H) Sp8 expression in the
forelimb bud in wild-type (G) and Dkk1/ (H)
embryos at E12.5. In Dkk1/ embryos, the
Sp8 expression is stronger in the AER (blue arrow) and ectopically
induced outside the AER (blue arrowhead).