Fig. 5

Horseradish peroxidase staining of H. limbata embryos using the Ubx/Abd-A (FP6.87) antibody (a–c, e, g, i), with corresponding DAPI stains (d, f, h). Early in embryogenesis, expression was not visible (a, b). The first apparent expression was observed in post-segmentation embryos as small posteriolateral patches in the T2 and T3 segments (arrows in c). Abdominal expression was stronger and extended through all abdominal segments until A10, with the strongest staining found in the A1 segment (c). Weak thoracic staining continued to appear in older embryos at the posteriolateral edges of T2 and T3 (arrowheads in e), with stronger expression in the lateral regions as compared to the midline. In addition, expression was strong at the posterior edge of T3 and the anterior edge of A1 (e, arrow). In the oldest embryos imaged, expression was present along the posterior boundaries of T2 and T3 (g), strongest at the posterior of T3 and anterior of A1, and remained through the abdomen, reducing in intensity toward the posterior segments (g). The posteriorolateral thoracic staining observed in segmented stages appears to extend close to the developing limbs, and possibly into the proximal limb structure (i, arrow). Staining is entirely absent from the distal tips of thoracic limbs (i, asterisk). T1–T3, thoracic segments; A1–A10, abdominal segments. Ventral view, anterior to the top for images a–h; lateral view, anterior to top in image i. Scale bars 0.10 mm. Magnifications are 200X for all images