Figure 3

Ectopic miR-34 overexpression in differentiated MB neurons disrupted γ axon pruning.

Confocal images show axon pruning of MB neurons in wild-type flies (a) and flies with ectopic miR-34 overexpression using the mosaic analysis with a repressible cell marker system (b,c). GAL4-201Y-driven mCD8::GFP (GFP) expression (green) reveals the morphology of γ lobes (arrowheads) and a subset of α and β lobes (arrows). In the lower panels, FasII staining (magenta) reveals the α and β lobes (strong magenta staining; arrows) and the medial γ lobes (faint magenta staining; arrowheads). A subset of the dorsal α lobe was observed on MB neurons in wild-type flies (upper arrow, a), whereas an aberrant axonal bundle (likely unpruned γ lobe) projected outside the MB α lobe (double arrowhead, b) and most of the γ lobes were intact in the sample with ectopic expression of one copy of mir-34 transgene (arrowhead, b). Defective γ lobe pruning was more severe in flies for ectopic overexpression of two copies of miR-34 transgenes in MB γ neurons (double arrowheads, c). Fly genotypes are listed in Supplemental Table 2. Scale bar: 10 μm for all panels.