Figure 3.

plexA and plexB dosage changes modify GlyRS^P234KY-associated axonal defects and mutant GlyRS accumulation at the neuromuscular junction (NMJ). (A–C) Digitally inverted images of the TN showing increased axonal bruchpilot (Brp) compared to control (A) upon ubiquitous (B) and muscle-specific (C) gars^P234KY expression. (D) The build-up of Brp in axons of the TN caused by ubiquitous GlyRS^P234KY expression is modulated by alterations in PlexA or PlexB levels. Greater Brp accumulation is observed upon PlexA reduction and PlexB overexpression, whereas an increase in PlexA and a decrease in PlexB ameliorate Brp build-up. N.b., gars^P234KY is not expressed in the plexA/+ and plexB/+ control flies (third and fourth bars from the y-axis, respectively). (E) An example of GlyRS^P234KY (HA staining) accumulation at the presynapse when ubiquitously expressed. (F) GlyRS^P234KY accumulates at the neuronal membrane, and correlates with PlexB, but not PlexA, levels, i.e., increased and decreased abundance of PlexB causes increased and decreased mutant GlyRS build-up, respectively. (G) When expressed with a ubiquitous driver, PlexB localizes at the NMJ with the neuronal marker HRP. (H) PlexB and GlyRS^P234KY localize to the NMJ when co-expressed using a ubiquitous driver. *P < 0.05, **P < 0.01, ***P < 0.001 Dunn’s/Bonferroni’s multiple comparison test. #: displayed a significant increase when compared to the mutant GlyRS background alone (Mann-Whitney U test, P = 0.03). All experiments are performed expressing gars^P234KY with a ubiquitous driver (1032-GAL4). Scale bar = 10 μm. For all experiments, n > 20 larvae per genotype. Error bars represent ± SEM. See also Supplementary Figure S4.