Fig. 4. The overexpression of dizzy in macrophages changes their cell shape. Macrophages overexpressing dizzy from a single copy of the allele dizzy^EP under the control of srph-gal4 (A,C,E,G,I; hereafter named dizzy^h.EP) have a significantly different cell shape from macrophages of wild-type embryos (B,D,F,H,J). (A,B) At stage 11, dizzy^h.EP macrophages migrate in a similar way to wild-type cells. (C) During and after migration through the embryo, dizzy^h.EP macrophages form long protrusions that contact each other and the substrate. These protrusions span dorsoventrally through the entire VNC (arrowhead). (D) In wild-type embryos, the protrusions are much smaller. (E) The change in cell form is maintained also in late embryos affecting the clearance of the VNC from macrophages (arrowhead). (F) In a wild-type embryo, macrophages have left the inner region of the VNC at stage 16. (G) In dorsolateral positions, the dizzy^h.EP macrophages form a network with their large cellular extensions. (H) In wild-type embryos, the cells are smaller and do not touch each other. (I,J) Magnifications of areas indicated in G and H. (K) Expression of dizzy from two copies of dizzy^EP also affects migration of macrophages, most strongly at stage 14.