Figure 3.

The activin dominant negative receptor (Act DN) down-regulates the expression of Siamois in whole embryos. (A) Act DN mRNA (500 pg) was injected into either the ventral (V) or dorsal (D) sub-equatorial region of four-cell stage embryos. Whole embryos were cultured to stage 10, and expression of Siamois as well as the SMAD2 responsive genes Xgsc, and Chd and the β-catenin responsive gene Xnr3 was analyzed by RNase protection assays. (B) The levels of expression of these genes has been quantitated relative to expression of the FGF-R loading control. This experiment was repeated twice and achieved the same result both times.