Fig. 1. The Tube localization gradient is enhanced in tub² mutant embryos. (A,B) Paired images from a wild-type embryo, showing a longitudinal optical section in the plane of the dorsoventral axis. The embryo is stained with fluorescein-conjugated antibodies to Dorsal (A) and with antibodies to Tube detected with a Cy3-conjugated secondary antibody (B). (C,D) Surface images of (C) a wild-type embryo and (D) a tub² embryo, stained with antibodies to Tube, ventrolateral aspect. In each image, an arrow indicates the approximate position of the ventral midline.