Figure 1. E-lineage reporter expression and intestine development.

In each panel, two groups of identically-staged wildtype and mutant embryos (left and right, respectively; divided by solid white line) expressing the same E-specific reporter were mounted together on a slide at around the 8-cell stage. Embryos were imaged for DIC and GFP fluorescence at the 2E stage (left 2 panels), and then imaged again 13 hours later for DIC and birefringent gut granules (right two panels). The mutation scored for each row is indicated on the left. The E-lineage reporter is indicated above the GFP fluorescence panels. Note that all mom-4(or39) mutant embryos express the Pend-1:gfp::h2b reporter, albeit at lower levels than in wildtype embryos. Solid outline: examples of embryos that are GFP positive at the 2E stage but do not develop gut granules. Dashed outline: examples of embryos that did not express the reporter at the 2E stage but nonetheless went on to generate gut granules. Gut granule birefringence can appear stronger in mutants because of failed morphogenesis leading to compaction of intestinal cells, compared to the fully elongated intestine in wildtype embryos. Bar: 50 µm.