Fig. 4. Extension of dendritic arborization of the larval LNs, caused by Kir2.1 expression in the visual system, and in a wild-type prepupa. (A,B) Whole-mount of a doubly stained CNS of w; GMR-gal4 UAS-gfp/+; UAS-Kir2.1/+ third instar larval brain. (A) Anti-PDF staining of the LNs. Arrowheads indicate the long PDF-immunoreactive extension (seen in 9/10 hemispheres, versus 0/6 for the third instar controls in the same experiment, not shown). Similar alterations were already detectable in the first larval stage (not shown). (B) GFP staining of the visual system. The BN ending is much thinner than normal (compare with Fig. 1C). (C,D) Whole-mount of a doubly stained CNS of control w; UAS-cd8-gfp; gal1118 at 4 hours after puparium formation (APF). CD8-GFP is used instead of GFP to label the processes of the LNs better. (C) CD8-GFP staining of LNs. The same kind of extension has been seen in about 10% of hemispheres from three independent experiments (also with pdf-gal4 driven UAS-gfp expression in the LNs) performed within approximately 6 hours around puparium formation. (D) Anti-chaoptin staining of the visual system. No morphological alterations were observed. APP, adult photoreceptors projections; BN, Bolwig nerve; DA, dendritic arborization of LNs; DP, dorsal projections of LNs; LNs, lateral neurons. Scale bar: 10 µm.