Stage 17 wus^G0162 mutant embryos show defects in the transition from luminal liquid-clearance to air-filled airways. Tube size defects and defective airway protein clearance are also seen. No air-filling defects are observed in wus^G0162 heterozygotes.

Hemizygous stage 16 embryos show an increase in tracheal length and diameter compared to wild type, resulting in curved tracheal branches.

Secretion of extracellular matrix (ECM) into the lumen of the tracheal tubes occurs normally in mutant embryos, but its organisation into the central chitin cylinder and the gap region fails to occur (an accumulation of chitin fibres is seen in the mutant tube lumens). In contrast to wild type, lumen clearance (the degradation of chitinous ECM and removal of protein and liquid) does not occur in late stage 17 mutant embryos, and as a consequence, gas filling fails to occur. The mutant animals die as late embryos.

The apical cell membranes of tracheal cells are enlarged in mutant embryos, being disorganised and containing folds that are likely to be due to extra-membrane material.

Endocytosis is defective in mutant epidermal cells (as seen by a reduction in uptake of a biotin tracer).

pio^17C, wus^G0162 has embryonic/larval tracheal dorsal trunk | embryonic stage phenotype

pio^17C, wus^G0162 has tracheal lumen | embryonic stage phenotype

pio^17C, wus^G0162 has larval tracheal system | embryonic stage phenotype

crb^11A22/crb[+], wus^G0162 has larval tracheal system | embryonic stage 17 phenotype

crb^j1B5/crb[+], wus^G0162 has larval tracheal system | embryonic stage 17 phenotype