Imprecise excision of P{EP}Cad99CGE21034 results in a large deletion covering the 5'UTR and exons 1-5, stopping approximately mid-way through the intron between exons 7 and 8 of Cad99C.
microvillus & follicle cell (with Cad99C21-6)
Cad99C21-8 mutant females lay ~50% fewer eggs than wild-type females, with <2% of those eggs producing larvae. These larvae develop into flies that only display defects if they are homozygous mutants. The majority of eggs from Cad99C21-8 mutant females collapse soon after deposition and even non-collapsed eggs are penetrable to vital dyes (e.g. trypan blue), which do not stain wild-type eggs. These defects suggest that eggshells, which normally restrict permeability and prevent desiccation, are compromised. Eggs from mutant females are also highly intolerant to sodium hydrochlorite. Hydrochlorite treatment of wild-type eggs removes the outer eggshell, the chorion, but leaves the inner eggshell, the vitelline membrane, intact. Disintegration of eggs from Cad99C21-8 mutant females in hydrochlorite suggests that the vitelline membrane is non-functional.
The vitelline membrane of Cad99C21-8 mutant follicles varies in thickness and contains numerous holes. This variability in eggshell defects may explain why mutant females are not fully sterile, allow a few embryos to develop.
Egg chambers of Cad99C21-8 mutants have vitelline bodies that are irregular in shape, size, and distribution.
Cad99C21-8/Cad99C21-6 mutant follicles exhibit a range of defects of microvilli. Microvilli appear substantially shorter than in wild-type. In many cases, apical protrusions appear reduced in number, and they form an irregular, spiky pattern, suggesting that microvilli are abnormally shaped and may be clumped. In other cases, no obvious protrusions are detected or only few microvilli with an abnormal, wavy shape protruded from the apical surface.
