(A) Detection of ttx-3 mRNA by smFISH in a wild type embryo at epidermal enclosure stage. Due to the time delay induced by protein synthesis, the optimal time point for detection of ttx-3 mRNA is in the SMDD/AIY mother cell, while the optimal time point for detection of TTX-3 proteins is a bit later in the early postmitotic AIY. Ventral view, anterior is left, scale bar = 10 μm. (B) Detection of ceh-10 mRNA by smFISH in a wild type embryo at 1.5-fold stage. In addition to AIY in the ventral head, ceh-10 mRNA are also present in a few other neurons in the dorsal head. Lateral view, anterior is left, dorsal is up. (C) Quantification of the number of ttx-3 mRNA in the SMDD/AIY mother cells of wild type or PRC1 mutant embryos at epidermal enclosure stage. Each dot represents one cell. The number of cells analyzed for each condition (wild type, mig-32(n4275) or spat-3(gk22)) is presented below the genotype. The red bars represent the mean and SD. A Mann-Whitney U-test was used to compare the medians (*<0.05, *** p<0.001). (D) Quantification of the number of ceh-10 mRNA in the AIY neurons of wild type or PRC1 mutant embryos at 1.5-fold stage.