UPR ^mt delayed the age-associated decline of import. (a and b) glp-1(e2141ts) worms were synchronized in two batches and grown at 25°C. When the two batches reached day 1 and 5 of adulthood, respectively, mitochondria were isolated in parallel and subjected to import assay with 30-min incubation time followed by Western blot analysis. Import efficiency was quantified by measuring the mature imported protein as detected by the DHFR antibody, followed by analysis with unpaired Student’s t test (two-tailed; b). Graph is presented as mean ± SD, n = 4. *, P < 0.05. Arrowheads, mature (imported) DHFR with the MTS cleaved off. (c)glp-1(e2141ts) worms were synchronized and grown at 25°C on bacteria expressing dsRNA from the time of hatching. RNA was isolated on day 5 of adulthood, and qPCR analysis was performed. Expression was normalized against three housekeeping genes. The graph is presented as mean ± SD, n = 2. *, P < 0.05. (d and e)glp-1(e2141ts) worms were synchronized and grown at 25°C on bacteria expressing dsRNA from the time of hatching. Mitochondria were isolated on day 1 of adulthood and subjected to import assay followed by Western blot analysis. Import efficiency was quantified by measuring the mature imported protein as detected by DHFR antibody, followed by analysis with unpaired Student’s t test (two-tailed; e). The graph is presented as mean ± SD, n = 2. *, P < 0.05; **, P < 0.01. Source data are available for this figure: SourceData F6.