FIGURE 3.

Cuticle defect phenotype in pst-1(tm3364), pst-2(tm3316), and pst-1(tm3364);pst-2(tm3316) C. elegans mutant adult animals. A–D, representative DIC images of regions behind the head (A and C) and tail (B and D) of wild-type L3 (A), wild-type late-L4 (B), pst-1(tm3364) mutant L3 (C), and pst-1(tm3364) mutant late-L4 larvae (D). Ph, posterior pharyngeal bulb; arrowhead (in C), in pst-1(tm3364) L3 larvae, some small protuberances of outer cuticle were observed, which were not observed in wild-type animals. During mid-L4 to the young adult stage, pst-1(tm3364) mutant animals showed abnormal molting (D). Bar = 30 μm. E, analysis of alkaline bleach sensitivity. The time to stop thrashing in alkaline bleach solution was an indicator of cuticle fragility. The pst-1(tm3364) mutant animals were more fragile (stopped faster) than the wild-type animals. In contrast, pst-2(tm3316) mutants showed cuticle fragility similar to wild-type animals. The pst-1(tm3364);pst-2(tm3316) double mutant animals were more fragile than the pst-1(tm3364) single mutant animals. In transgenic pst-1(tm3364) mutant animals that carried an extrachromosomal array of P_dpy-7::pst-1b::egfp or P_unc-119::pst-1b::egfp, the cuticle fragility was restored to the wild-type level, but the former was slightly more fragile than the latter. In transgenic pst-1(tm3364) mutant animals that carried an extrachromosomal array of P_dpy-7::pst-2::egfp, the cuticle fragility was similar to that of pst-1(tm3364) mutants without the transgene. Ex, extrachromosomal array; N.S. = not significant. **, p < 0.01; ***, p < 0.001; assessed by two-tailed Student's t test.