a, BrdU staining of germ line from wild-type C. elegans fed with the indicated RNAi from day 1 of adulthood. Worms were examined at day 5 of adulthood. Cell nuclei were stained with DAPI. Scale bar represents 20 µm. The images are representative of 3 independent experiments. b, Graph represents the percentage of BrdU-positive cells/total nuclei (mean ± s.e.m., Vector, cbs-1 RNAi (n= 46 germ lines), cct-2, cct-5, hsp-1, ama-1 RNAi (n= 40), germ lines scored per each condition from 3 independent experiments). Statistical comparisons were made by two-tailed Student’s t-test for unpaired samples. P-value: **** (P<0.0001). c, Muscle-specific knockdown (KD) of cbs-1 decreases lifespan extension induced by cold temperature (15°C). RNAi rescued in the muscle of RNAi-deficient worms (rde-1(ne300); myo-3p::rde-1 strain). Empty vector RNAi mean ± s.e.m: 29.49 ± 0.81; cbs-1 RNAi: 25.33 ± 0.90, P=0.0048. d, Neuronal-specific KD of cbs-1 does not affect longevity at 15°C. RNAi rescued in the neurons of RNAi-deficient worms (sid-1(pk3321); unc-119p::sid-1 strain). Empty vector RNAi mean ± s.e.m: 26.09 ± 0.60; cbs-1 RNAi: 25.78 ± 0.51, P=0.3367. e, Intestinal-specific KD of cbs-1 decreases longevity at 15°C. RNAi rescued in the intestine of RNAi-deficient worms (rde-1(ne219); nhx-2p::rde-1 strain). Empty vector RNAi mean ± s.e.m: 25.02 ± 0.66; cbs-1 RNAi: 22.25 ± 0.65, P<0.0001. f, RNAi rescued in both the intestine and germ line of RNAi-deficient worms (rde-1(ne219); mex-5p::rde-1 strain). Empty vector RNAi mean ± s.e.m: 26.97 ± 0.79; cbs-1 RNAi: 22.72 ± 1.00, P<0.0019. g, Percentage of mean lifespan change in different strains upon knockdown of cbs-1 (relative to the respective empty vector RNAi control). Graph represents the mean ± s.e.m. from 3 independent lifespan experiments for each strain. Longevity was not further reduced when both the intestine and the germ line responded to RNAi treatment when compared to knockdown in the intestine alone (KD intestine versus KD intestine + germ line, P= 0.2634). Statistical comparisons were made by two-tailed Student’s t-test for unpaired samples. NS= not significant. h, Knockdown of cbs-1 in the germ line alone does not decrease cold-induced longevity at 15°C. RNAi rescued in the germ line of RNAi-deficient worms (rde-1(mkc36); sun-1p::rde-1::sun-1 3'UTR strain). Empty vector RNAi mean ± s.e.m: 28.32 ± 0.55; cbs-1 RNAi: 28.40 ± 0.64, P=0.5733. In all the lifespan experiments, P-values: two-sided log-rank test, n= 96 worms/condition. RNAi was started at day 1 of adulthood. See Supplementary Data 3 for statistical analysis and replicate data of lifespan experiments.