Figure 3.

Injured synapses retain functional neurotransmission properties in raw mutants. A, Example traces for EJP and mEJP potentials recorded from muscle 6 NMJs in control/WT (Canton S), raw^dcp-1(dcp-1^prev1) homozygous animals and animals expressing UAS-Raw-RA cDNA in motoneurons (via the D42-Gal4 driver) in a raw^dcp-1/raw^134.47 mutant background. Recordings were done at segment 3 or 4 from naive (uninjured) animals, and in B, in animals 20 h after a ventral nerve crush that injured the nerves innervating these segments. NMJs in raw^dcp-1/raw^134.47 mutants expressing Raw cDNA in motoneurons showed three phenotypic classes: 6/20recorded NMJs of this genotype retained both EJPs and mEJPs similarly to uninjured NMJs, in left example traces; 12/20 retained mEJPs but lost EJPs, in right traces, and 2/20 lacked both EJPs and mEJPs, similarly to WT injured, indicating partial rescue of the raw phenotype. C, Quantification of EJP amplitude, mEJP amplitude, quantal content (corrected for nonlinear summation), and mEJP frequency (Hz) for recordings from uninjured (black) and 20 h postinjury (red) larvae. D, Percentage of NMJs in the three different phenotypic classes depicted in A. n ≥ 15 NMJs per condition. ****p < 0.0001.