Fig. 1
dnrx-1 mutations disrupted Rh5 restriction in the retina. (A-C) Frozen sections of adult heads expressing UAS-n-Synaptobrevin-GFP (nSyb-GFP) under control of the R8p-specific driver Rh5-GAL4 (i.e. Rh5 > nSyb-GFP), were stained with anti-GFP (green) and MAb24B10 (magenta). MAb24B10 recognizes the cell adhesion molecule Chaoptin expressed in all R-cell axons [54]. (A and A’) In wild type (n = 8), R1-R6 axons terminate in the lamina (la), while R7 and R8 axons pass through the lamina and terminate at distinctive layers of the medulla (me), M6 and M3 respectively. Among R8 axons, about 30% and ~ 70% were GFP-positive R8p axons (arrowhead) and GFP-negative R8y axons (arrow), respectively. (B and B’) In nrx-1MI10278 homozygous mutants (n = 12), the number of R8p axons showed a dramatic increase. (C) The percentage of Rh5-positive axons were quantified. Compared to that in wild type, the percentage of Rh5-positive axons were increased significantly in nrx-1MI10278 homozygous mutants (***p < 0.001). Similar increase in the percentage of Rh5-positive axons was also observed in nrx-1MI10278/Df(3R)Exel6191 transheterozygotes (n = 12; ***p < 0.001). Total number of axons counted in wild-type flies: Rh5-positive axons, 447; all R8 axons, 1366, nrx-1MI10278 homozygous mutants: Rh5-positive axons, 1687; all R8 axons, 2639, and nrx-1MI10278/Df(3R)Exel6191 transheterozygotes: Rh5-positive axons, 1135; all R8 axons, 2415. (D-F) Frozen sections of adult heads expressing UAS-nSyb-GFP under control of the R8y-specific driver Rh6-GAL4 (i.e. Rh6 > nSyb-GFP), were stained with anti-GFP (green) and MAb24B10 (magenta). (D and D’) In wild type (n = 7), about 70% of R8 axons in the medulla were GFP-positive R8y axons. (E and E’) nrx-1MI10278 homozygous mutants (n = 8). (F) The percentage of Rh6-positive axons were quantified. Compared to that in wild type, no significant difference in the percentage of Rh6-positive axons was observed in nrx-1MI10278 homozygous mutants. ns, p > 0.05. Error bars indicate SD. Scale bar, 20 μm