Fig. 7. The heterochronic gene lin-14 affects zig-4 gene expression but not PVT cell fate. (A) zig-4::gfp (otIs20) expression in PVT (white arrow) is absent in lin-14 mutants. See Table 2 for quantification of defects. The small arrows indicate a pair of non-identified tail neurons that can be occasionally observed to express zig-4::gfp in wild-type animals, but show stronger and more consistent expression in lin-14 mutant animals. (B) PVT adopts its normal fate in lin-14(n179) mutants. 21/21 late L1/L2 stage animals show normal expression of unc-47::gfp (otIs39) in PVT and normal PVT axon morphology (white arrows indicate the cell body and axon of PVT; for wild-type control, see Fig. 4A). All strains were grown at 25°C. PVT cell fate is also unaffected as assessed with a pin-2::gfp (otIs85) marker (data not shown).