Fig. 5

UNC-34 EVH1 domain is required for UNC-34 localization. A Schematic showing UNC-34 constructs used in the rescue experiments. B and C Live animal imaging of developing PVD dendrites in L3 stage wild-type animals that express wild-type UNC-34:GFP (B), or unc-34 null animals that express UNC-34ΔEVH:GFP (C). PVD dendrite morphology was visualized using a myristoylated-mCherry morphology marker (ser2prom3 > myr-mCh). White arrows indicate tip localization of UNC-34:GFP in filopodia. White arrowheads indicate swelling localization of UNC-34:GFP before filopodia initiation. White asterisk indicates large growth cone-mediated growth lacking UNC-34ΔEVH:GFP enrichment at tip. Scale bar is 2 µm. Kymographs of dendrite growth are presented on the right. D and E Quantification of UNC-34:GFP enrichment to swellings before branch initiation. GFP intensity was measured at branching sites prior to branch outgrowth. Note the peak of UNC-34:GFP signal at 1 min before branch formation is absent in worms expressing the ΔEVH construct. Statistical comparison was performed between the -1.75 min (baseline) and -1.0 min timepoints using the Wilcoxon matched-pairs signed rank test. (***, p < 0.001; ns, p > 0.05; n = 28 branches for wild-type UNC-34:GFP; n = 25 branches for UNC-34ΔEVH:GFP). F Quantification of UNC-34:GFP enrichment at dendrite tips. GFP intensity was measured at the tip of a growing dendrite and normalized as % increase in intensity compared to GFP intensity along the dendrite shaft. Each data point is the average measured from 4–10 branches from a single worm. Statistical comparison was performed using the two-tailed Mann–Whitney test (*, p < 0.05; n = 8 worms for wild-type, n = 9 worms for UNC-34ΔEVH:GFP)