Fig. 6. Expression of optix in mutations for exd and hth. Expression of optix (green) in exd (A,C) and hth (B,D) mutant embryos, and cuticle preparations (E,F). (A,B) Stage 12; (C,D) retracted germ band stage. Expression of optix is strongest in the maxillary (Mx), labial (Lb) and thoracic segments and weaker in A1-7. There is no significant expression of optix in the A8, where AbdB is detected (A,B), nor in A9 segments. There is a stronger segmentation defect in exd compared with hth embryos. In the thorax of exd and hth (E,F insets), crinkled head-like cuticle differentiates. A and B are lateral views, C-F are ventral views.