SNB-1-GFP is reduced at GABAergic synapses and accumulates in cell bodies in <i>mec-15</i> mutants.

<p>(<b>A</b>) Representative fluorescence images of SNB-1-GFP in neurites of GABAergic motor neurons in the posterior dorsal nerve cord from wild-type animals and <i>mec-15</i> mutants. <i>mec-15</i> mutants have reduced fluorescence intensity of SNB-1-GFP puncta compared to wild-type animals. Expression of <i>mec-15</i> in GABAergic neurons rescues this phenotype (rescue 2). Right panels show quantifications of puncta fluorescence and densities. Reduced puncta fluorescence of <i>mec-15</i> mutants is rescued by expressing <i>mec-15</i> in GABAergic motor neurons (two rescuing lines are shown). (<b>B</b>) Representative fluorescence images (left) and summary data (right) are shown for GFP-tagged SNB-1 in posterior dorsal cord axons of cholinergic motor neurons (expressed with the <i>unc-129</i> promoter) in wild-type and mec-15 animals. Right panels show quantifications. No significant differences were observed. (<b>C</b>) Representative fluorescence images of the GABAergic cell bodies DD5 and VD10 from wild-type animals and <i>mec-15</i> mutants expressing the synaptic vesicle protein SNB-1-GFP in GABAergic motor neurons (arrows and arrowheads point to DD5 and VD10, respectively). The right panels show quantifications. <i>mec-15</i> mutants have increased fluorescence intensity of SNB-1-GFP in cell bodies compared to wild-type animals. (<b>D</b>) Representative fluorescence images of RAB-3-GFP in neurites of GABAergic motor neurons in the posterior dorsal nerve cord from wild-type animals and <i>mec-15</i> mutants. Right panels show quantifications of puncta fluorescence and densities. Puncta fluorescence and synapse density are normal in <i>mec-15</i> mutants. (<b>E</b>) As in (D) except that GFP-tagged SYD-2 (liprin-α) was expressed. Neither puncta fluorescence nor synapse density is changed in <i>mec-15</i> mutants. All data are means +/− SEM from 20–30 images (A, B, D, E) or 15–20 cell bodies (C). **p<0.001, *p<0.01, Student’s t-test. Scale bars = 10 µm (A, B, D, E) and 5 µm (C).