The expression of smt3dsRNA.Scer\UAS under the control of Scer\GAL4salm.EPv leads to a small but significant decrease in the total wing area, coupled with a severe area decrease of the intervein region between L2 and L3, as compared to controls; expression under the control of Scer\GAL4phm.PO leads to a complete development arrest at the larval stage.
The follicle cells in flies expressing smt3dsRNA.Scer\UAS under the control of Scer\GAL4T155 show a strong reduction in the number of lipid droplets. Egg fertility is only slightly affected and viable embryos are obtained.
The prothoracic gland cells in larvae expressing smt3dsRNA.Scer\UAS under the control of Scer\GAL4phm.PO have a reduced lipid content.
Expression of smt3dsRNA.Scer\UAS under the control of Scer\GAL4GMR.PF does not result in a mutant phenotype in the eye.
Expression of smt3dsRNA.Scer\UAS under the control of Scer\GAL4ey.PU results in a dramatic reduction in the size of the eye disc and severely reduced adult eyes. In many cases, head formation is abolished and the animals do not eclose.
Animals expressing smt3dsRNA.Scer\UAS under the control of Scer\GAL4phm.PO arrest their development at the third larval instar just before pupariation and survive to an additional 3 weeks. During this time, the larvae continue feeding and gain weight. Mutant third instar larvae fed with medium containing 20-hydroxyecdysone pupariate within 24 hours, but do not develop further.
At 120-144 hours after egg laying (AEL), some prothoracic gland cells in larvae expressing smt3dsRNA.Scer\UAS under the control of Scer\GAL4phm.PO are increased in size. The nuclei of these cells are enlarged and show abnormal morphology. From 7 to 22 days AEL in the mutant larvae, the prothoracic gland cells and their nuclei continue to grow in size, and at the same time, the number of prothoracic gland cells progressively decreases. Massive cell death or degeneration are not seen in the mutant prothoracic glands. The cells show a decrease in the number of lipid droplets per cell compared to wild type.
Ultrastructurally, the prothoracic gland cells of larvae expressing smt3dsRNA.Scer\UAS under the control of Scer\GAL4phm.PO show a clear reduction in the number and length of invaginations of the plasma membrane compared to wild-type cells. The number, size and morphology of the mitochondria appear normal. The nuclear lamina appears thickened, but nuclear pores appear not to be affected.