hrp48 is required to prevent overextension of MB dorsal axonal branches.

(A, B) Axonal projections of wild-type (A) or hrp48^7E7-18 (B) neuroblast (Nb) clones labelled by mCD8-GFP and generated using the MARCM technique. Arrow in B points to ectopically projecting axonal branches. Scale bar: 20μm. (C) Percentages of Nb clones exhibiting « normal » projections (ie dorsal branches stopping at the end of the dorsal lobe), or ectopic projections. Numbers represent numbers of scored Nb clones. Re-expression of a wild-type copy of Hrp48 (Flag-Hrp48) rescues the MARCM mutant phenotypes (***, p<0.001 in a χ² test). Precise genotypes: hsp-flp, UAS-mCD8-GFP/+; FRT40A/FRT40A tub-Gal80;;OK107-Gal4/+ (A); hsp-flp, UAS-mCD8-GFP/+; FRT40A, hrp48^7E7-18/ FRT40A tub-Gal80;;OK107-Gal4/+ (B).