cortical actin cytoskeleton & oocyte, with Scer\GAL4Myc-PG45
microvillus & follicle cell, with Scer\GAL4Myc-PG45
Expression of psddsRNA.Scer\UAS under the control of Scer\GAL4Act5C.PI results in only about 5% of embryos hatching.
Expression of psddsRNA.Scer\UAS under the control of Scer\GAL4dm-PG45 results in early embryonic arrest, with less than 1% of embryos hatching as larvae.
All eggs laid by females expressing psddsRNA.Scer\UAS under the control of Scer\GAL4dm-PG45 have grossly normal chorion morphology. However, up to 10% of laid eggs are collapsed at or soon after deposition (the remainder do not collapse over time). After dechorionation, most of the mutant eggs are permeable to neutral red dye and the vitelline membranes are difficult to remove with methanol, characteristics of defects in vitelline membrane integrity. The neutral red permeability of the eggs shows a strong preference for anterior staining near the micropyle. Fertilisation of the eggs does not appear to be compromised, however, the majority of the embryos arrest prior to cellularisation. Less than 10% of the embryos proceed to cellularisation, and all but rare escapers arrest at or before germband extension.
Most embryos derived from females expressing psddsRNA.Scer\UAS under the control of Scer\GAL4dm-PG45 have abnormally condensed chromatin, which is generally seen in all nuclei in the embryo. In some cases, individual chromosomes can be discerned at the periphery of the nucleus, but more commonly, the chromatin appears as a continuous ring around the periphery of the nucleus. There are also frequent empty spots and irregularities in the depth of cortical nuclei in syncytial blastoderm embryos, and chromatin strands occasionally extend between adjacent nuclei during the earlier cleavage divisions.
Embryos derived from females expressing psddsRNA.Scer\UAS under the control of Scer\GAL4dm-PG45 do not show apoptosis, except for TUNEL labeling of many nuclei in a few late-arresting embryos.
Defects are seen in the initial organisation of the vitelline bodies in egg chambers expressing psddsRNA.Scer\UAS under the control of Scer\GAL4dm-PG45; the mutant vitelline bodes are irregular in size, sometimes very large or small, and unevenly spaced, giving rise to a "boulders and gaps" appearance in stage 10A. These structures coalesce with approximately normal timing, giving rise to a continuous vitelline membrane that ranges in thickness from normal to about half wild-type thickness. Small holes can be seen in the mutant vitelline membrane at stage 11, but no full thickness gaps are seen. The development of the inner chorionic layer and endochorion appears normal in the mutant egg chambers.
The follicle cells of stage 10A egg chambers expressing psddsRNA.Scer\UAS under the control of Scer\GAL4dm-PG45 show grossly disorganised microvilli. There is a widening of the perivitelline space between the oocyte and the follicle cell epithelium compared to in wild type. The cortical F-actin cytoskeleton of the oocyte shows irregularities and a scalloped appearance.