Fig. 2. Effects of xTsg and xTsg^W67G on neural patterning and dorsal development. (A-D) Expression of Sox-2 at stage 12 in embryos either uninjected (A), or microinjected in the animal pole at the four-cell stage with a total of 1 ng xTsg mRNA (B), 4 ng xTsg mRNA (C) or 1 ng xTsg^W67G mRNA (D). (E,F) Expression of N-tubulin at stage 14 in wild-type embryos (E), or embryos microinjected at the two to four cell stage with 1 ng of xTsg (F), Xolloid (G) or xTsg^W67G (H) mRNA. At least 10 embryos per sample were stained in each of two independent experiments. (I) Embryo injected four times into the marginal region at the two to four cell stage with 250 pg xTsg^W67G mRNA. (J) Embryo co-injected with 250 pg Tsg^W67G and 250 pg dominant-negative BMP receptor (tBR) mRNA. (K,L) Sox-2 in situ hybridization of stage 42 embryos. (M-O) Histological sections of control, xTsg and xTsg^W67G injected embryos. sc, spinal cord; so, somites; no, notochord; pn, pronephros.