egl1/egl4 zygotic mutant larvae display normal neuromuscular junction (NMJ) morphology and muscle size, and their locomotion appears normal.
egl1/egl4 third instar larvae have no defects in the localisation of nuclei in the optic stalk or retina.
Embryos derived from egl3e/egl1 mothers mated to egl4/+ fathers often show a disrupted epidermis. At stage 13, the salivary gland placode area is often disrupted. Salivary gland morphogenesis is disrupted in that cells of the placode often do not change their apices in a coordinated way; the invagination hole appears too large and extended; and the invaginated portion of the glands often has an irregular shape.
All 16 cells of developing egl1/egl4 mutant ovaries initially enter mitosis and form a synaptonemal complex. The synaptonemal complex dissolves in later egg chambers and all 16 cells become polyploid nurse cells.
16 cell vitellarial cysts cease to enlarge partway down the vitellarium and are eventually phagocytosed. Cyst production dynamics are normal. All 16 nuclei in a cyst enter meiosis; the chromatin condenses and synaptonemal complex is present. Later all 16 lose the synaptonemal complex and assume nurse cell characteristics. Cell shape changes within the cyst are normal as the cysts pass down the germarium. Synaptonemal complex is of normal width and is apparently normal in substructure, but throughout pachytene it maintains the extreme thinness typical of wild-type synaptonemal complex during zygotene. Most "pachytene" nuclei in egl mutant cysts have zygotene numbers of synaptonemal complex segments as well as zygotene thinness. The nuclei do mount both early and late recombination nodules, at normal positions within the germarium. Number of recombination nodules per nucleus is comparable to that in wild type pro-oocyte. The onset of cytoplasmic flow is delayed. In mid-vitellarium the 16 cells remain the same size. Ring canals frequently do not enlarge as much as they should, and are more likely to be lacking their inner lining than in wild type. The fusome is apparently normal. Centrioles and mitochondria orient normally. Centriole replication continues. Mitochondria indicate that the ring canals may be unusually difficult to pass through.
Egg chambers contain 16 nurse cells and no oocyte, many egg chambers are degenerating.