Fig. 1. abu/pqn paralog group genes are up-regulated during cuticle synthesis.

(A) Pictures of a wild-type posterior pharynx at the start (0 minutes after pumping cessation) and middle (45 minutes after pumping cessation) of the fourth larval stage (L4) lethargus period. Thin and thick arrows denote the L4 and adult grinders, respectively. Anterior is to the left. Scale bar is 10 µm. (B) Width of the grinder as a function of time after hatching. First larval stage (L1) was 0–15 hours after hatching and the second larval stage was 18–26 hours after hatching. L1 lethargus occurred between 15 and 18 hours after hatching. Each point corresponds to one worm. Linear regression of the data within each larval stage produced lines with slopes that were not significantly different from zero (one-way ANOVA, p>0.1). (C) Illustration of C. elegans larval development. L1–L4 denotes larval stages 1–4, and Leth denotes lethargus. Numbers above the figure denote hours after hatching. Arrows mark sampling times for RNA collections. Dark arrows correspond to samples collected in this study whereas gray arrows correspond to sampling collected in Baugh at el. (Baugh et al., 2009). Venn diagrams illustrate logic used to define the L4 lethargus gene set and the Cuticle gene set. (D) The 13 most highly-expressed abu/pqn genes identified in all stages of cuticular synthesis. Shown is the fold change in the four comparisons. Additional genes in the abu/pqn paralog group are listed in supplementary material Table S5.