Fig. 3.

Effects of dSirt4 on starvation, activity, and fertility. (A) dSirt4 knockout (KO) flies are starvation-sensitive relative to genetically w¹¹¹⁸ matched controls (w¹¹¹⁸: median survival = 41 h, mean = 40.9 h, n = 96; dSirt4 KO: median survival = 32 h, mean = 34.1 h, n = 97). Male flies are shown, log-rank P < 10⁻¹⁰. (B) Flies overexpressing dSirt4 ubiquitously (da-GAL4 > UAS-dSirt4) are starvation-resistant relative to da-GAL4 > w¹¹¹⁸ controls (control: median survival = 43 h, mean = 43.1 h, n = 100; dSirt4 transgenic: median survival = 49 h, mean = 48.8 h, n = 99). Male are flies shown, log-rank P < 10⁻¹⁰. (C) dSirt4 transcript levels increase upon overnight (16 h) fasting in fat bodies of 10-d-old wild-type female flies. Data represent mean of three biological replicates, and error bars are SEM (P < 0.01, unpaired two-tailed t test on delta threshold cycle values). (D, Left) dSirt4 KO flies have decreased spontaneous activity compared with controls over a 3-d period. Gray shading indicates the dark period (12-h cycle). (D, Right) Bar graph displays total, light period, and dark period counts shown in the activity plot. Data represent the average of three replicate vials, with 20 female flies per vial on high-calorie (15% SY) food, and are presented as the number of counts per 30-min bin per fly. (E) dSirt4 KO flies exhibit impaired fertility relative to controls. Cumulative eggs laid are shown for both genotypes on both high-calorie (HC: 15% SY) and low-calorie (LC: 5% SY) diets. n = 10 vials, five flies per vial. Error bars represent SEM (P < 0.01, unpaired two-tailed t test) between genotypes at all time points for both diets.