Gross midgut morphogenesis during embryonic development is not impaired in Df(3L)Ssk animals.
Only a small number of Df(3L)Ssk embryos hatch to first instar larvae, and those that do are sluggish in their movements and do not survive to the second instar stage.
The anterior midgut epithelial cells of late stage 17 Df(3L)Ssk embryos are more elongated in the apical-basal direction than those of wild type. While the wild type cells are cuboidal with a slightly rounded apical surface composed of microvilli, Df(3L)Ssk anterior midgut cells have apical membranes with microvilli often protruding into the lumen, though these cells do retain their apicobasal polarity.
In the midgut of late stage 17 Df(3L)Ssk embryos, parallel plasma membranes between cells are markedly reduced and intercellular spaces of irregular width are often observed. The intercellular space lacks electron-dense material and septa are observed at a much lower frequency than in wild type. The characteristic septa of smooth septate junctions is barely detectable.
The morphology of pleated septate junctions in the hindgut of late stage 17 Df(3L)Ssk embryos is normal, with parallel plasma membranes containing clear septa.
