Fig. 5. vhnf1 functions as a repressor of anterior identity independently of Fgf and val functions. (A-H) Overexpression of vhnf1 marked by co-injected lacZ (light blue stain). Panels labeled lacZ have only lacZ RNA injected. Dorsal view, anterior to the top. (A-F) hoxb1a expression (purple) and krox20 expression (orange) at six-somite stage. (A-C) vhnf1 does not affect hoxb1a expression at 100% epiboly (A) but represses hoxb1a expression (B). krox20 expression marks future r3 and r5 domains (orange). (C) When lacZ alone is injected, no repression of hoxb1a is observed. (D) Injection of vhnf1 into valentino (val) mutant embryos results in repression of hoxb1a expression at the six-somite stage and repression of the anterior (r3) krox20 expression. (E) Co-injection of fgf3 and fgf8-targeted morpholino oligos with vhnf1 RNA results in repression of hoxb1a expression. (F) Coinjection of fgf3 and fgf8 MOs with lacZ RNA has no effect on hoxb1a expression. (G,H) Expression of fgf8 RNA at tailbud stage. Injection of vhnf1 represses the anterior hindbrain expression of fgf8 (G), whereas injection of lacZ alone has no effect on fgf8 expression (H).