Figure 3.

Genetic mapping of tubule cell types. (A) Lines c324 and c374 distinguish subsets of morphologically indistinguishable principal epithelial cells in the main segment. (B) Lines c710 and c724 are expressed uniquely in the stellate cells of adults and larvae. (C) Lines c710 and c724 also mark bar-shaped cells in the initial segment of anterior tubules. (D) Type II cell morphology switches from bar-shaped to stellate at the transitional–main tubule boundary (arrow). The tip of the tubule is to the left. (E) Line c649 marks only the bar-shaped type II cells of anterior tubule initial and transitional segments. (F) Line c325 demonstrates the presence of a small, previously unreported cell type in the lower tubules and ureter and of homologues in the posterior midgut.