Fig. 5. Inhibition of XNF-ATc3 signaling does not inhibit CE in the mesoderm. Animal caps were treated as follows: (A) uninjected control, (B) uninjected control treated with activin, (C) injected with 250 pg CA XNF-ATc3 (CA) and treated with activin, (D) injected with 500 pg CA XNF-ATc3 and treated with activin, (E) injected with 1 ng DN XNF-ATc3 (DN) treated with activin, and (F) treated with 400 nM CsA and activin. Injection of DN XNF-ATc3 did not inhibit CE even at concentrations of 4 ng DN XNF-ATc3. The same was seen in animal caps treated with 4 mM CsA or 400 nM CsA plus FK506, a calcineurin inhibitor that is know to show synergistic effects with CsA (Flanagan et al., 1991; Liu et al., 1991). (G,H) DN XNF-ATc3 also failed to inhibit CE in Keller explants overexpressing 2 ng DN XNF-ATc3 and 200 pg GFP. All seven explants from two experiments elongated. (G) Bright-field of an elongating Keller explant. (H) GFP fluorescence of G.