Figure 3. Transcription factor Fos specifically mediates axonal overgrowth induced by Wnd.

(A) Loss of the Drosophila fos, kay, blocks axonal overgrowth caused by Wnd overexpression. Shown are representative axon terminals of ddaC MARCM clones of following genotypes: (1) wt; (2) overexpressing Wnd with MARCM (OE Wnd); (3) kay¹; (4) overexpressing Wnd in kay¹ genetic background with MARCM (OE Wnd+kay¹). Scale bar, 10 µm. (B–B′) kay¹ impairs dendritic growth in wt genetic background and exacerbates the dendritic reduction caused by Wnd overexpression. Shown are representative dendrites (B) and tracings (B′) of ddaC MARCM clones of indicated genotypes. Scale bar, 50 µm. (C) Bar charts showing the quantification of axon terminal length (left), total dendrite length (middle), and number of dendrite termini (right).