Fig. 3. Expression of Xgly4 is induced by dorsalizing signals during gastrulation. Injections of ß-gal (100 pg; red) mRNA alone into ventral (A) or dorsal (E) regions did not affect Xgly4 expression pattern. However, expression of Xgly4 (purple) was detected by whole-mount in situ hybridization in the ventral side of embryos dorsalized with mRNA injection of Xnr1 (100 pg; B), ß-catenin (100 pg; C) or the dominant-negative BMP receptor ALK3 (100 pg; D) with ß-gal mRNA into the ventral region. Expression of Xgly4 was suppressed in embryo ventralized with Bmp4 mRNA (100 pg; F) and ß-gal mRNA injected into the dorsal region. Arrows indicate the injection sites.