ATP6AP2 bearing a deletion of the ER retrieval motif is expressed under the control of its own regulatory region.
ATP6AP2Δ1 homozygotes bearing ATP6AP2L98S display severe mortality during the pupal stage; the surviving adult display poor mobility, decreased or absent climbing capabilities, blistered wings, and reduced head size and die 3 to 4 days after eclosion, as compared to controls.