Fig. 4
Neuronal activity requires Fmi to instruct C4da topography. a, b Representative images of the dorsal-ventral view of single C4da terminals (green) and the C4da neuropil marked by ppk-tdTomato (red). c, d are statistic results of the axon terminals index of three neurons of C4da. a, c Inhibition of neuronal activity by overexpressing Kir2.1. b, d Inhibition of the neuronal activity of C4da neurons by overexpressing ORK△NC as WT and ORK△C. Both c, d showed that in the fmi mutant neurons, the regulation of neuronal activity on topography disappeared. c WT: D, n = 22; M, n = 18; V, n = 23; OE Kir2.1: D, n = 23; M, n = 20; V, n = 24; fmiE59 + OE Kir2.1: D, n = 16; M, n = 19; V, n = 24. d WT: D, n = 22; M, n = 23; V, n = 23; OE ORK△C: D, n = 28; M, n = 30; V, n = 28; fmiE59 + OE ORK△C: D, n = 26; M, n = 24; V, n = 27. e Inhibition of neuronal activity does not affect the axonal shortening caused by loss of fmi. f Inhibition of neuronal activity can rescue the increased branch’s number of axon terminals caused by fmi mutations. D, ddaC; M, v’ada; V, vdaB. *P < 0.05; **P < 0.01; ***P < 0.001; N.S., no significant difference. Scale bar, 2 μm. Error bars indicate mean ± SEM. WT: n = 22; OE Kir2.1: n = 20; fmiE59 + OE Kir2.1: n = 17