Major NE distortions were observed in unc-84(n369) muscle nuclei. (A–D) Representative thin-section TEM micrographs of L1 larval body wall muscles. (A and B) Wild-type nuclei with normal (A) and slightly distorted (B; arrow shows ∼100-nm separation) nuclear membranes. (C and D) Large distortions were observed at the ends of unc-84(n369) nuclei. (E) Quantitation of the maximum PNS at the ends of ≥10 nuclei of each genotype. unc-84(n369) nuclei had a significantly larger mean space than wild type (P = 0.0021). The horizontal bars denote the mean values. Bar, 500 nm. (F) Mean frequency of head thrashing for wild-type and unc-84(n369) L1 larvae. Error bars are 95% confidence intervals assuming Poisson distribution. (G and H) Blue traces represent the mean motion spectra for wild type and unc-84(n369); shaded regions represent standard deviation of the mean. The asterisk indicates the secondary harmonic peak. a.u., arbitrary unit.