P{PZ} insertion in the first intron, 232bp upstream of the translation start site.
2% of homozygous embryos show misguided and stalled terminal tracheal branches at 25oC. Females containing homozygous germline clones have normal egg chamber morphology but show reduced egg production. 82% of eggs derived from these females are abnormal; 64% have expanded dorsal appendages, 12% have a single fused or circumferential dorsal appendage, 5% have multiple dorsal appendages and 1% have no dorsal appendage.
A. Spradling.
Excision of the P{PZ} element can revert lethality.