Figure 7. LIN-39 is an activator of VD terminal identity genes.

(A) Schematic summarizing unc-30 and lin-39 expression in VD and DD neurons populating the VNC. In addition, 4 VD and 2 DD neurons are located in ganglia flanking the VNC (not shown because they were excluded from our analysis). Raw data on lin-39 expression described in Figure 4—figure supplement 2. (B) Quantification of two VD (ser-2::gfp, oig-1::gfp) and one DD (flp-13::gfp) markers in WT and lin-39 (n1760) animals at L4. Both VD markers were also tested in unc-30 (e191) mutants. Double lin-39 (n1760); unc-30 (e191) mutants showed a more severe reduction in expression of the VD marker ser-2::gfp compared to each single mutant. N > 15. ***p<0.001. N. S: not significant. (C) Auxin or ethanol (control) were administered at larval stage 3 (L3) on lin-39::mNG::3xFLAG::AID; eft-3::TIR1 animals carrying the VD marker ser-2::gfp. Images were taken at the young adult stage (day 1.5). A significant decrease in the number of MNs expressing the VD marker was evident in the auxin-treated animals compared to EtOH-treated controls. Similar results were obtained when auxin administration occurred at L4 or day one adult animals. For comparison, quantification of marker expression is also provided in WT and lin-39 (n1760) animals. N > 15. **p<0.01, ***p<0.001. N. S: not significant. (D) Several terminal identity markers of cholinergic neurons (acr-2, slo-2, unc-129, del-1) are not ectopically expressed in unc-30-depleted GABAergic MNs. A strong loss-of-function allele e191 for unc-30 was used (Brenner, 1974; Eastman et al., 1999). Arrowheads point to MN cell bodies with gfp marker expression. Green fluorescence signal is shown in white for better contrast. (E) Quantification of data presented in panel D. N. S: not significant. (F) Schematic summarizing the function of LIN-39 and UNC-30 in GABAergic VD neurons. LIN-39 site is taken from Weirauch et al. (2014). UNC-30 site is taken from Yu et al. (2017).