Mutants show defects in destruction of the larval salivary glands, having persistant larval salivary glands at the pupal stage.
At the onset of pupation, as staged by head eversion, Eip74EFneo24
mutant animals exhibit the following phenotypes: 1. Mutant larval midguts are extremely condensed and the adult and larval epithelia have separated such that a defined adult lumen exists. These mutants also form an adult midgut epithelium, and the larval proventriculus and gastric caeca are destroyed. Thus, Eip74EFneo24
larval midguts appear to be arrested at a stage of destruction that is similar to the midgut of wild-type animals 6-12 h following puparium formation. 2. DNA fragmentation is detected in all larval midgut cells of mutant animals 3. Mutant larval midgut cells appear to die normally and have numerous autophagic structures, including mitochondria in vacuoles, crystalline inclusions, and myelin-like membrane swirls. Between the white prepua stage and head eversion, Eip74EFneo24
mutant midguts decrease in length by an average of 81% in length compared to 85% in the wild-type.
mutant pupae exhibit DNA fragmentation in the salivary gland as normal.
Mutant salivary gland cells lack large eosin positive vacuoles and plasma membranes and show variable chromosome banding - phenotypes associated with autophagy initiating in salivary gland cells but not progressing. Salivary gland cells contain nascent autophagic vacuoles composed of rough endoplasmic reticulum enclosing cytoplasmic components including mitochondria and smaller vacuoles.
Approximately 20% of Eip74EFneo24
animals have salivary glands at 24 hours after puparium formation, in contrast to wild-type pupae where they are completely destroyed by 16 hours after puparium formation.
Homozygous mutant γ neurons (generated in the brain as somatic clones) exhibit no detectable abnormalities in larval or adult stages.
Head eversion is not affected in mutants.
Development of hemizygous pupae progresses normally but tanning is delayed by several hours. Some fail to form a gas bubble or undergo pupation. Homozygous and hemizygous pharate adults dissected from the pupal case display leg twitches and abdominal contractions and are inviable.