Mutant embryos have elongated trachea.
pckG0012 mutant embryos are characterised by an elongated and tortuous dorsal trunk, the main trachea, and by irregular and stretched dorsal trunk cells.
The dorsal trunk of pckG0012 homozygous embryos exhibits an elongated and convoluted lumen. The tracheal pericellular-diffusion barrier is compromised in pckG0012 mutants.
In pckG0012 mutants, the lumenal chitin in the developing dorsal trunk of the tracheal system fails to form a filamentous cable running along the tube length, as in wild-type, but instead is amorphous and fills the lumen.
Elongated and tortuous tracheal branches, most prominantly in the dorsal trunk. Pleated septate junctions are absent from tracheal cells; intercellular cleft is instead filled with unstructured electron-dense material. Germline clone analysis revealed that embryos lacking maternal pck function form a normal tracheal system and develop into fertile adults. Zygotic mutant phenotype is indistinguishable from that of embryos lacking both maternal and zygotic component pck. Transepithelial barrier function is affected - rhodamine labelled dextran diffuses across the epithelial sheet.