Pre-synaptic sites in R7 axons redirected to ectopic layers.

<p>(A-D) R7 and R8 axon terminals are stained with mAb24B10 (red), and presynaptic active zones in R7 axons are visualized by Brp-short^cherry fluorescence (green). R7 axons target the M6 layer in the wild type (A), whereas the R7 axons (marked by two white arrowheads) that overexpressed Caps (B) or Gogo and Fmi (C) were redirected to the M3 layer. Overexpression of Unc5 misdirected R7 to the more superficial layer M0-1 (D). Scale bars represent 10μm. (E) Quantification of Brp-short^cherry puncta per R7 axon terminal. The number of the puncta was reduced in Unc5-overexpressing R7s. (F) Brp-short^cherry distribution in R7 photoreceptor axons. In Caps-overexpressing R7s, the synaptic markers are essentially shifted from the M6 to the M3 layer. In contrast, Brp-short^cherry distribution in R7s overexpressing Gogo and Fmi was similar to that of R8 photoreceptors. * p<0.05, ** p<0.01, ***p<0.001 (t test) (GMR>caps VS GMR>gogo, <i>fmi</i>). Error bars represent s.d.