Figure 6.

Synaptic release is affected in ari-1 mutants.A, mEJC frequency in ari-1 mutants is reduced. Representative traces from a spontaneous mEJCs recording. Events were captured under TEVC (Vh = –80 mV) from larval muscle 6 fibers in ari² mutant male (top) and in heterozygous ari²/+ female siblings (bottom). B, quantification of the effects over spontaneous release. mEJC frequency (mean ± SEM) was calculated from the following larvae strains; (wt), ari²♂ covered by the duplication Dp(1;3)JC153 (ari²;Dp), heterozygous ari² female siblings (ari²/+ ♀), ari²♂ and two additional ari alleles (ari³ and ari⁴), and their respective heterozygous females. Student's t test. Note the consistent reduction of mEJC frequency across all mutant genotypes with respect to the sibling female controls. ari² is a C150Y mutation in the first R motif of the RBR domain; ari³ is a C309Y mutation in the second R motif; and ari⁴ is a point mutation that generates a STOP codon at amino acid 91. C, neither size nor mEJC time course is affected in ari² animals. Cumulative probability curve of mEJC amplitudes for ari²/+ ♀ (black) and ari²♂ (red) larvae (n = 7 larvae). Inset: average representative mEJC traces from ari²♂ mutant superimposed to that of ari²/+ ♀. Traces were scaled up to the maximum peak value. D, representative traces of evoked transmitter release recorded under TEVC (Vh = −80 mV), at increasing extracellular Ca²⁺ concentrations (from 0.3 to 1.2 mM), recorded from sibling ari²/+ ♀ and ari²♂ larvae. E, quantification of Ca²⁺ dependence of evoked release. Maximal EJC response was plotted versus the extracellular calcium concentration for ari²♂ compared with ari²/+ ♀ (n = 6 for all genotypes; one-way ANOVA post hoc: Student's t test). F, quantification of EJC trains in response to a 10 Hz stimulation. Peak size was normalized to their initial response. Average of six different experiments from ari²♂ and ari²/+ ♀ larvae.