Fig. 4. Over-expression of Xnr3 induces convergent extension movement and the expression of Xbra, eFGF, MyoD and NCAM in animal caps. (A) Morphology of animal cap explants injected at the 2-cell stage with a dose response of Xnr3 mRNA (125 pg-1 ng), dissected at late blastula (stage 9) and photographed at the late neurula stage (stage 20). Elongation is dose responsive. Convergent extension occurs during the neurula stages. (B) Xbra, eFGF, eomesodermin, MyoD and NCAM expression is induced in animal caps injected with Xnr3 mRNA. 250 or 500 pg Xnr3 RNA was injected at the animal pole into two cells of the 2-cell-stage embryo. Animal caps were dissected at stage 9. Gene expressions were analyzed by real-time RT-PCR at stage 11 (for eomesodermin, Xbra and eFGF), and stage 28 (for NCAM and MyoD). In each case, ornithine decarboxylase (ODC) was used as a loading control (data not shown), and each bar was normalized to the level of ODC expression. ND, not done.