Figure 6.
Age-onset toxicity requires continuous DPR expression. (A) Images of worms expressing the indicated DPR under the control of a heat shock inducible promoter. Red fluorescence shows the myo-3p::mCherry transgenic marker. Green fluorescence shows the hsp-16.2p::DPR–GFP signal. All DPRs are shown 2–4 h after heat shock. Insets show an enlarged view of the region identified by the dashed boxes. Arrows in the (GA)50 inset point to putative protein aggregates, suggesting that (GA)50 rapidly aggregates after synthesis. Arrows in the (PR)50 inset point to sites of nuclear localization in the intestine. No such nuclear localization was observed in the (GR)50 line after heat shock. (B) Developmental toxicity of transgenic embryos expressing the indicated hsp-16.2p::DPR–GFP. Embryos were heat shocked at 35 °C for 30 min and then returned to 20 °C. The number that reached ≥L4 after 48 h were scored as ‘growth’ while the remaining animals were scored as ‘no growth’. N ≥ 81 transgenic animals per condition. ***P < 0.001 (Fisher’s exact test versus GFP + H.S.). (C) Adult toxicity of animals expressing either hsp-16.2p::GFP or hsp-16.2p:(PR)50-GFP. Animals were subjected to either a heat shock (30 min, 35 °C) on Day 1, Day 4 or on Days 1, 2, 3 and 4. Every 24 h, animals were scored as either mobile, censored or affected (paralyzed + dead = ‘% with phenotype’). Heat shock induction of (GA)50, (PA)50 and (GR)50 produced phenotypes identical to that of GFP. N ≥ 60 animals per genotype. ***P < 0.001 versus GFP; Days 1–4 H.S (Log-rank test with Bonferroni adjusted P-value).