Homozygous pio2R-16 embryos have a tracheal disintegration phenotype similar to Df(2R)Px2 homozygotes. All tracheal branches except the dorsal trunk and the dorsal branch of the first tracheal metamere undergo disintegration. The branches that undergo disintegration include the cerebral branch, ventral cephalic, pharyngeal branch, dorsal branch, visceral branch, transverse connective, lateral trunk anterior, lateral trunk posterior and ganglionic branch. Instead of fine tracheal tubes, in homozygous pio2R-16 embryos these are transformed into hollow cysts. However, the dorsal trunk is not affected, indicating that pio2R-16 embryos exhibit an absence of tubes with autocellular adherens junctions. The subsequent differentiation of the dorsal branches does not seem to be affected in pio2R-16 homozygous embryos. Terminal branch formation or integrity is not detectably affected in pio2R-16 homozygous embryos. In addition, the formation of fusion tubes between the bilateral dorsal branches along the dorsal midline occurs normally in pio2R-16 homozygous embryos. prevented by a pim+ transgene.
Homozygous clones in the wing produce large blisters that lack sharp boundaries. Wings are sometimes rumpled. Homozygous embryos show excessive contractions of the segmental muscles just before hatching. The posterior segments are compacted and the muscles appear shorter than normal.
Homozygous clones in the wing produce a blistered phenotype.