Fig. 5. Symmetrical division of GMC-1 in sli mutants is caused by the up regulation of Nub. Anterior end is up, only half segments are shown in these panels. Embryos in panels A-H are double stained for Nub (red) and Eve (green; Eve only panels are not shown). GMC-1 is marked by arrow; U and aCC/pCC neurons are marked by arrowheads. Scale bars, 10 µm. A,C,E and G show Nub staining; B,D,F and H show Eve, Nub merged images. (A,B) Wild-type embryo; note the high levels of Nub in GMC-1 (arrow). (C,D) sli mutant embryo. (E,F) Wild-type embryo; note the down regulation of Nub in GMC-1. (G,H) sli mutant embryo; note that the level of Nub in GMC-1 is not down regulated. Similar results were also observed with Miti. (I,J) Eve-stained hs-miti embryos, the GMC-1 symmetrically divides to generate two RP2s. (K) Eve and Zfh-1 stained wild-type embryo, the asymmetric division of GMC-1 has generated an Eve-positive but Zfh-1-negative smaller sib and a larger Eve- and Zfh-1-positive RP2. (L) Eve and Zfh-1 stained hs-miti embryo. In the upper right hemisegment, the GMC-1 has generated two RP2s whereas in the lower right hemisegment, the GMC-1 has divided normally to generate RP2 and sib. (M) Eve (green) and Insc (red) stained hs-miti embryo where miti is ectopically expressed before GMC-1 division. Note that Insc expression is non-asymmetric. Similar results were also observed with over-expression of nub.