Mutant tracheal terminal cells show a gas-filling defect at the stalk cell to terminal cell connection - most gaps are present in heterozygous stalk cell tubes adjacent to Vha13cnj-356 mutant cell clones. The defects are 100% penetrant with late onset (third larval instar). The stalk cell-terminal cell interface is also affected: 25% of Vha13cnj-356 cells exhibit stalk cells aberrantly forming two or more connections to a neighbouring terminal cell, and 8% of Vha13cnj-356 cells show a more severe defect in which long, branched autocellular, seamed tubes extend well beyond the terminal cell nucleus. These ectopic, seamed tubes derive from the adjacent stalk cell.
Vha13cnj-356 dorsal trunk clones are not fully integrated into the epithelium - cells are oval (not hexagonal) in shape and have a significant decrease in the amount of apical membrane. Vha13cnj-356 stalk cell clones have abnormal autocellular and intercellular junctions - these cells are detached from the epithelium or contribute a very short segment of autocellular tube.
Tubulogenesis in Vha13cnj-356 embryos is intact, and tube defects are only observed in clones later in larval development - ie. tube architecture only becomes disrupted over time as the the tracheal system increases in size.
conjoined356 mutants exhibit thick and severely pruned tracheal terminal cells. There is also defective intercalation/auto-cellular tube formation. They also exhibit an auto-/sub-cellular tube gas-filling defect. Dorsal trunk cells are rounded and contribute minimally to multicellular lumen.