Fig. 7.

Zipper/Myosin heavy chain accumulates at both A and P cell edges within denticle field cells. (A) A cartoon cross-section of the ventral epithelium, showing gene expression domains and the correspondence to the prospective smooth or denticle field. Black or white brackets A–C indicate one parasegmental unit. Denticle rows 1 through 7 are indicated as are Wingless-, Engrailed-, Rhomboid- and Serrate-expressing cells (W, E, R, S). The domain of expression of Ptc-GAL4 UAS-SlamHA (red) and En-GAL4 UAS-SlamHA (blue) is indicated by bars. (B) Ptc-GAL4 UAS-SlamHA embryo at stage 14 stained with anti-HA (green; Bʺ) and phalloidin (red; B′). The relevant interface to consider for this experiment is the one between row 2 cells, which express SlamHA (indicated by red asterisk), and the previous row 1 cells, which do not. It is unambiguous that Slam, and, thus, MyoII are enriched at the A edge of row 2 cells (Arrows). (C) En-GAL4 UAS-SlamHA embryo at stage 14 stained with anti-HA. It is obvious that Slam is enriched at cell interfaces. The relevant one to consider for this experiment is the one between row 1 cells (indicated by blue asterisk), which express SlamHA, and row 2 cells, which do not. It is unambiguous that Slam, and, thus, MyoII are enriched at the P edge of row 1 cells (Arrows). We conclude that MyoII accumulates in a bipolar manner on A and P cell edges within prospective denticle field cells. Scale bar = 20 μm.