Figure 4. GABAA Receptor Clustering Is Impaired in the Absence of MADD-4 and NRX-1(A-C) Confocal micrographs showing the dorsal nerve cord of 20 wild-type (A),
nrx-1(
wy778) (B), and
madd-4(
ok2854) (C) mutant animals.(D and E) Quantification of UNC-49::YFP puncta maximum fluorescence intensity (D) and synaptic density (E) in wild-type,
nrx-1(
wy778), and
madd-4(
ok2854)animals. An ANOVA and post hoc Tukey's tests were used to determine significant differences between the different genotypes. Error bars indicate SEM. p valuesare *** < 0.001.(F) Confocal micrographs showing the dorsal and ventral nerve cords of a wild-type and
madd-4;
nrx-1 double mutant animal expressing UNC-49::YFP. Toppanels show a higher magnification of the dorsal nerve cord.(G) A transgene carrying a genomic fragment of
nrx-1 fused to an SL2::GFP shows expression in GABAergic neurons, labeled in red (asterisks), as well as otherventral nerve cord neurons.(H) NRX-1::GFP localizes to inhibitory presynaptic sites, labeled with the active zone marker UNC-10::TdT.(I) Specific expression of a
nrx-1 minigene in GABAergic neurons induces GABAAR clusters in
madd-4;
nrx-1 double mutants.(J) Quantification of GABAAR clustering in the
madd-4;
nrx-1 double mutant in the absence or presence of NRX-1 in GABAergic neurons. p < 0.001, Fisher's exacttest. Scale bar: 10 m=um (A-C), 3 um (F-I).