Fig. 6.

Further characterization of the snail2 morphant phenotype. (A-E) Xenopus C2/C3 blastomeres were injected with snail2 MO. Compared with uninjected embryos (A), snail2 morphants displayed a reduction in sox9 expression at stage 17/18 (B). This reduction was rescued by the injection of 25 pg/embryo bmp4 RNA (C), wnt8 RNA (D), or the two RNAs together (E). In the case of wnt8 RNA injection, there was often evidence of the formation of a secondary axis (D, line to the right). (F) The percentage of snail2 MO C2/C3 injected embryos rescued (red bar) using 25 pg/embryo fgf8, wnt8, bmp4 or wnt8 and bmp4 (25 pg each) RNAs is shown. (G) In a similar study, lower amounts (10 pg/embryo) of bmp4 and wnt8 RNAs were used. Rescue was observed only when bmp4 and wnt8 RNAs were injected together. (H,I) In situ analysis indicated that the levels and extent of chordin expression increased in stage 11 C2/C3 snail2 morphant embryos (I, versus control in H). (J) At stage 10.5-11, DLMZ from snail2, snail1 or twist1 morphant C2/C3 dorsolateral zones were dissected, RNA was isolated and subjected to qPCR analysis. This revealed reproducible increases in the levels of sizzled, cerberus and chordin RNAs and decreases in the levels of wnt8, bmp4 and frzb1 RNAs; distinct patterns of change were observed in snail1 and twist1 morphant DLMZ. Error bars indicate s.d.