Fig. 5: PUFA biosynthesis genes are required for drl-1-mediated life-span extension.

a Schematic representation of the PUFA biosynthesis pathway in C. elegans. b, c Life span is extended when drl-1 is knocked down in WT, but not to the same extent in fat-6(tm331);fat-7(wa36) (b) or fat-2(wa17) (c). d Life span of eat-2(ad465) is suppressed in eat-2(ad465);fat-2(tm789). e In bacterial dilution-induced DR (BDR), fat-2(wa17) failed to produce a bell-shaped curve like WT. Bacterial culture of OD₆₀₀ = 3.0 was the starting concentration for serial dilution. The increase in life span when WT was maintained at OD₆₀₀ = 0.5, 0.25, or 0.125 was significant as compared to OD₆₀₀ = 3.0 (green stars); the difference in case of fat-2(wa17) was not. Two-way ANOVA-Tukey’s multiple comparisons test. *P = 0.0346, **P = 0.0087 (for OD₆₀₀ 0.5), **P = 0.0029 (for OD₆₀₀ 0.25). The average life spans of WT at dilutions OD₆₀₀ = 0.5 was significantly different from fat-2(wa17) (purple stars). Unpaired two-tailed t test. **P = 0.0036. Life spans were performed at 25 °C. Data presented as mean life span ± SEM. n = 2 biologically independent replicates. Life-span summary is provided in Supplementary Table 1. f The expression of selected CyTP genes are upregulated when drl-1 is knocked down. The expression of several of them are dependent on fat-2, as determined by QRT-PCR. Expression levels were normalized to actin. n = 7 (cyp-33C8), n = 6 (ftn-1), n = 5 (cyp-32B1, cyp-35B1), n = 4 (gst-6, nhr-31, ugt-50), n = 3 (nhr-206), or n = 2 (gst-19) biologically independent samples. Data are presented as mean values ± SEM. Unpaired two-tailed t test. g Western blot analysis of WT and fat-2(wa17) showing that drl-1 RNAi upregulates phospho-PMK-1. The levels of phospho-PMK-1 is already upregulated in fat-2(-) and is not further upregulated when drl-1 is knocked down. One of two independent experiments shown. h The expression of Pcyp-35B1::gfp is enhanced at YA stage when drl-1 is knocked down using RNAi, compared to control RNAi. However, fat-2(wa17);Pcyp-35B1::gfp already has elevated expression of GFP, and drl-1 RNAi failed to further increase it. Representative images from one of three independent experiments shown. Multiple overlapping images were acquired at ×100 magnification to cover the entire worm body and stitched together to generate a contiguous image. Source data are provided as a Source data file. All experiments were performed at 25 °C.