Figure 8.

png-1 and rad-23 act in a common genetic pathway to limit axon branching at the vulva. A, Genomic and protein structure of RAD-23 showing position and size of the tm2595 deletion and position of conserved UBL, UBA, and XPC domains. B, C, AVL axons, visualized in an Punc-25::GFP; unc-30(e191) background, displaying inappropriate branching (arrows) at the vulva (arrowheads) in rad-23(tm2595) (B) and png-1(cy9); rad-23(tm2595) (C) adult worms. D, The penetrance of vulval branches in L4 animals do not significantly differ in png-1 single and png-1; rad-23 double mutants, indicating that these genes act in the same genetic pathway to prevent ectopic AVL branching. E–H, DVB axons, visualized using an Pflp-10::GFP reporter, displaying overextension defects (arrows) in rad-23(tm2595) (E) and png-1(cy9); rad-23(tm2595) (G, I) at the vulva (arrowheads) in adult worms. A subset of overextended DVB axons also display inappropriate branching (arrows) at the vulva (arrowhead) (F, H). The penetrance of overextension (I) or branching (J) defects in L4 animals do not significantly differ in png-1 single and png-1; rad-23 double mutants, indicating these genes act in the same genetic pathway to prevent DVB overextension and ectopic branching. AVL and DVB defects are not observed (D) or are less severe (I) when counts are performed before vulval organogenesis at L3. Scale bars: B, C, 10 μm; E–H, 20 μm. Error bars for rad-23 genomic rescue denote SE of proportion. *p < 0.05; n = 51. Error bars for all other data denote SEM. χ² analysis was used to determine that double mutants do not significantly differ (ns) from single mutants.