Physiological IRE-1-XBP-1 and PEK-1 Signaling in Caenorhabditis elegans Larval Development and Immunity
(A) Detection of xbp-1 mRNA splicing by IRE-1 in the C. elegans xbp-1(zc12) mutant. Schematic of the unspliced and spliced xbp-1 mRNA, noting the position of the premature termination codon present in the xbp-1(zc12) allele. The smg-2(qd101) mutation results in inactivation of the NMD pathway, stabilizing the xbp-1(zc12) mRNA for detection. (B) Quantitative real-time PCR measurements of mRNA levels in the xbp-1(zc12) and smg-2(qd101);xbp-1(zc12) mutants relative to the smg-2(qd101) mutant synchronized in the L3 stage. (C) Quantitative real-time PCR measurements of levels of total and spliced xbp-1 mRNA in the smg-2(qd101) strain relative to WT grown to the L3 stage and then shifted to plates with or without tunicamycin (5 µg/mL) for 4 h. (D) Larval development and survival assay showing the proportion of animals of each of the indicated strains that reach the indicated stage after 4 d of development from eggs laid on plates containing tunicamycin (2.5 µg/mL) at 16°C. (E) Quantitative real-time PCR measurements of levels of total and spliced xbp-1 mRNA in the smg-2(qd101); xbp-1(zc12) strain relative to the smg-2(qd101) strain treated as in C. (In B, C, and E, values represent fold change ± s.e.m., n = 3 independent experiments, *P<0.05, ***P<0.001, two-way ANOVA with Bonferroni post test).