Fig. 4

Differentiation in hab mutants after gastrulation. Embryos were genotyped after completion of photography as outlined in the Experimental Procedures section. A: Expression of hatching gland gene and Krox20, five-somite stage in wild-type (A) and hab^-/-(A′), dorsoanterior view. Note ectopic hatching gland cell (arrow) below pollster in the mutant. B: FoxD3/forkhead 6, 10-somite stage in zygotic maternal dominant hab^-/+ and hab^-/-. Side view except for B′, which is a dorsal view. Note weak expression in mutant tail bud. Dorsal view shows bilateral somites (indicated by asterisks) forming on either side of the germ ring. C: alpha-collagen2a, 14-somite stage in wild-type (side view) and hab^-/- (dorsal view of kinked notochord). C′: Higher magnification image of the boxed regions. D: delta A,18-somite stage in wild-type (dorsal view, D) and hab^-/- (dorsal view and side view, D′). E: Zn12 antibody, 24 hr in wild-type (E) and rare hab^-/- escaper (E′), dorsal view. Note bifurcation of axis in mutant. cg, cranial ganglia; fp, floor plate; hb, hindbrain; hcd, hypochord; llf, lateral longitudinal fascicle; mb, midbrain; ncd, notochord; ncr, neural crest; os, optic stalk; ov, otic vesicles; pol, polster; r3, rhombomere3; r5, rhombomere5; rb, Rohan-Beard cells; sc, spinal cord; tbm, tail bud mesenchyme; tg, trigeminal. Arrows indicate the width of the axis.