Fig. 5.

Targeting of Shaker clusters to Type I synapses is altered in dlg mutants containing only PDZ1–2 but can be rescued by postsynaptic dlg targeting. A, Anti-Shaker immunoreactivity indlg^m52. In these mutants Shaker clusters (arrow) are formed at ectopic muscle regions.B, High-magnification view of ectopic clusters in muscles 12 and 13 of a dlg^m52sample.  Arrows indicate the localization of synaptic boutons determined by double labeling with anti-HRP antibodies (data not shown). C, Anti-Shaker immunoreactivity in adlg^m52 strain carrying the P[Gal-4] element BG487, which expresses Gal-4 in a subset of muscles, and UAS-dlg. Note that in this strain clustering of Shaker channels around Type I synapses is normal and that only small ectopic clusters are observed (arrow). Scale bars: A, 90 μm; B, 25 μm;C, 20 μm.