FLP-mediated recombination has resulted in the deletion of the entire EMC3 coding region.
Approximate boundaries of a deletion of the entire EMC3 coding region generated by FLP-mediated recombination. Uncertainty in boundaries due to uncertaintly in progenitor insertion location.
EMC3Δ4 mutant photoreceptors in late pupal flies exhibit massive amplification of the endoplasmic reticulum. The sheet structure is no longer maintained and the cytoplasmic space is filled with ER membrane with a larger luminal space. Golgi bodies are also swollen and dilated, and sometimes vesiculated. The rhabdomeres in EMC3Δ4 mutant photoreceptors are quite small and thin but the adherens junctions and basolateral membrane exhibit normal morphology.
Ommatidial formation appears unaffected in EMC3Δ4 mutant photoreceptor clones but electron microscopy shows that rhabdomeres are shorter in EMC3Δ4 mutant pupal photoreceptors than in wild type and their microvilli are shorter.
Three day old EMC3Δ4 mutant photoreceptor clones reared in 12 hour light: 12 hour dark conditions exhibit retinal degeneration in a light-dependent manner, with the rhabdomeres invaginating into the cytoplasm. No microvilli defects or invaginations are observed at 17 days. This phenotype is seen in R1-6 and R7 photoreceptors.
