Dg is present at the membranes of all visceral myotubes, but concentrates at the edges of the visceral bands that completely extend over the midgut endoderm.

Dg protein is also expressed in three symmetric clusters on the lateral sides of the neuropil in thoracic segements of the larval ventral nerve cord.

An antibody specific to the Dg-PC isoform shows Dg protein present in cells posterior to the morphogenetic furrow. Staining is present before cells are positive for the neuronal marker 24B10 indicating that Dg expression precedes commitment to a neuronal fate. In additon to localization on photoreceptor cells, Dg expression is observed at the basal surface of the eye disc in the anterior region prior to and at the morphogenetic furrow. In early pupae (40% pupal development) Dg staining is found at the apical suface of neurons with less intense staining at the lateral surfaces of photoreceptor cells. Antibodies that recognize all Dg isoforms give similar results.

A longer isoform of the Dg protein (Dg-PC) is expressed between 2.5 and 20 hours of embryogenesis. A shorter form of the protein (predominantly Dg-PB) is produced after 6 hours of embryogenesis and is the predominant form in later stages. An antibody directed against the longer alternative exon detects Dg protein (reported to be Dg-PC) throughout embryogenesis. Expression is observed at the syncytial blastoderm stage in the plasma membrane. During cellularization, expression splits into two domains and is observed at the future apical cell membrane and basally in the furrow canal. During gastrulation, Dg-PC protein is concentrated at the apical side of cells that form the cephalic furrow, the amnioproctodeal invagination, and the ventral furrow. Weaker staining is observed at the basal side of the blastoderm embryo. At stages 9-10, protein is highly concentrated at the interface between ectoderm and mesoderm. After segregation of neuroblasts, expression is detected between the neuroblasts and the visceral mesoderm as well as weaker expression in the anterior and posterior midguts, the mesoderm, and the pole cells. Epidermal expression persists throughout embryogenesis. Dg-PC protein is also expressed in gonads, on axons of the CNS, and in a punctate pattern between the neuronal cell bodies of the ventral nerve cord that may represent cortex glia. Expression is also observed in the hindgut, in the gastric cecae, at the interface between visceral mesoderm and anterior midgut rudiment, in the PNS, in midgut constrictions, and in an unidentified group of segmentally repeating cells in the developing epidermis, close to the amnioserosa. Staining with antibodies directed agains Dg exon 8, the cytoplasmic domain, or the C-terminus give different staining results. Anti-exon-8 detects expression from around embryonic stage 5 while the C-term antibody detects expression from stage 14. The anti-cyto and C-term antibodies detect expression in the dorsal median cells. The anti C-term antibody was used to describe the expression of the shorter isofrom, Dg-PB. Expression of Dg-PB is first observed at embryonic stage 14 in the dorsal median cells. At stage 16, expression is observed in the pharynx, gastric cecae, hindgut, Malpighian tubules, and midgut constrictions. At stage 17, expression is found in the dorsal vessel, the cap cells of the chordotonal organs, and the gonads. Expression is observed in perineural cells that ensheath the peripheral nerves and the ventral nerve cord. The main Dg protein isoforms detected, Dg-PB and Dg-PC exhibit developmentally regulated and tissue-specific expression patterns. Both forms are expressed in some tissues including hindgut, midgut constrictions, gastric cecae, and gonads. Other tissues express one of the other (Dg-PC in blastoderm, visceral mesoderm, epidermis, tracheal pits and Dg-PB in dorsal vessel, chordotonal organs, dorsal median cells, and perineurial cells). In the nervous system, one isoform is found predominantly on axons while the other is on cells ensheathing the nervous system.

Dg protein is expressed in the adult eye, brain, and the developing larval brain and visual system, especially in optic lobes and photoreceptors. In the larval optic lobe, Dg protein is present both on photoreceptor axons in the optic stalk, lamina plexus and medulla neuropil, and in the repo‐expressing brain glial cells.