The ntl gene interacts with kny and ppt, but not slb. At 26 hpf, the tail extends beyond the yolk extension (ye) in wild-type embryos (A). Embryos with the slb mutation (B) have normal tails, whereas ppt (C), kny (D) and ntl (E) embryos have shorter tails (*). Embryos with the slb;ntl double mutation (F) have cyclopic eyes (ey) and tail defects like individual mutants, and slb;ppt (G) double mutants are shorter than individual mutants. The tail does not extend beyond the yolk tube in ppt;ntl (H) and kny;ntl (I) double-mutant embryos. At the ten-somite stage, slb/wnt11 is expressed in the notochord of wild-type (J) embryos but is absent in ntl mutants (K). Posterior ppt/wnt5 expression is mediolaterally broader in wild-type (L) but persists in ntl (M) embryos, and kny expression is comparable between the wild type (N) and ntl mutants (O). (A-I) Lateral views. (J-O) Dorsal posterior views. Scale bar=50 μm (A-I) and 100 μm (J-O).