FIGURE 2:

Onset of dlg-1 RNA and protein expression in epithelia. dlg-1 RNA is pseudocolored magenta (top); DLG-1 protein is labeled in white (bottom). RNA and protein data are from different embryos. Nuclei of the epidermis (A–F) and 4E midgut (G) are visualized by DAPI (blue). PHA-4::GFP (green) marks the midgut (H–L), foregut (M–R), and arcade cells (white bars in Q and R). (A–F) dlg-1 RNA is first detected in the 4E epidermis (A), whereas the onset of protein expression is at the 8E stage (B). RNA and protein are continuously expressed throughout the 16E and morphogenetic stages (C–F). Note that the protein first forms spot junctions (B, C), which resolve into continuous bands (D–F). (G–L) The midgut first expresses RNA at the 8E stage and protein at the early 16E. The protein first forms spot junctions (I), which quickly resolve into continuous bands (J). The RNA and protein are also detected during morphogenesis (K, L). (M–R) Like the midgut, RNA expression in the foregut begins at the 8E stage (N). Unlike the midgut, protein expression is first visible as spots by the mid rather than the early 16E stage (compare I vs. O and P). Foregut cells have formed continuous junctions by the comma stage (Q). The arcade cells (between the white bars) have RNA but no protein at the comma stage (Q), and between the comma and 1.5-fold, the arcade cells express protein and form continuous junctions (R). All images are maximum intensity projections. Anterior is to the left. Scale bars, 5 μm. Embryos were fixed and either hybridized with probes to detect RNA expression or stained with antibodies to detect protein. The midgut and foregut/arcade cell images are from the same embryo; the epidermis images at the same stage are from different embryos. smFISH data were imported into Imaris 3D software (Materials and Methods).