FIG. 3.

The dys gene is expressed in multiple cell types. Dys localization was analyzed by immunostaining whole-mount embryos with α-Dys antisera, followed by AP histochemistry. Visualization is by Nomarski optics. (A to C) The embryo is at stage 14; anterior is to the left. (A) Dorsal view. Dys protein is present in anterior cells corresponding to foregut atrial precursors (arrowhead A), nervous system cells in part of either the medial brain or the frontal ganglion (arrowhead NS), the leading edge of the dorsal epidermis (arrowhead LE), tracheal fusion cells of the dorsal branch (arrowhead DB), hindgut (arrowhead HG), and anal pad (arrowhead AP). (B) Sagittal view illustrating tracheal fusion cell staining of dorsal branch (arrowhead DB), dorsal trunk (arrowhead DT), lateral trunk (arrowhead LT), and ganglionic branch (arrowhead GB). Atrial cells and nervous system staining are indicated as in panel A. (C) Ventral view showing dys expression in the ganglionic branch fusion cells (arrowhead GB) that later fuse to form the ventral anastomoses, and lateral trunk fusion cells (arrowhead LT). The ventral midline is indicated by an asterisk. (D) Dorsal view of a stage 13 embryo hybridized in situ with dys antisense DIG RNA probe. Hybridization (arrowheads) was detected in the same cell types as observed in panel A for Dys antibody staining. (E) Sagittal view of a stage 13 embryo hybridized to a dys antisense probe showing hybridization to the same cell types that stained with anti-Dys in panel B. (F) Sagittal view of a stage 14 Df(3R)Espl3 homozygous mutant embryo stained with α-Dys. Df(3R)Espl3 is deleted of the dys gene. There is a complete absence of α-Dys staining in all cell types, which confirms the specificity of the α-Dys staining. The parental strain contained a Kr-Gal4 UAS-GFP balancer chromosome, and Df(3R)Espl3 homozygous mutants were selected based on their absence of GFP expression.