Figure 4. Forced Expression of UPR^mt Genes is Sufficient to Preserve Muscle and Mitochondrial Function.

(A) Lifespan curves of flies expressing Hsp60 and Hsp60C outcrossed to w1118 flies, compared to Mhc-Gal4 flies outcrossed to w1118 flies.

(B) Lifespan curves of flies expressing Hsp60 or Hsp60C crossed to Mhc-Gal4, compared to Mhc-Gal4 flies crossed to w1118 flies. All transgenes result in an increase in lifespan relative to the background control. Note that the Mhc-w1118 curves are the same in A and B, as the lifespan assays in A and B were performed concurrently.

(C-E) Relative ATP levels, CS activity levels and DLD activity levels respectively, of thoraxes from flies with the genotypes listed, after 5 weeks at 25C. Figure labeling is as follows: (i) Mhc-Gal4 crossed to w1118 labeled as Mhc-w1118 (negative control), (ii) w1118 (i.e as wildtype flies), (iii) UAS-hsp60 insertion #1 crossed to w1118 labeled as 60-1-w1118 (control for insertion site #1), (iv) UAS-hsp60 insertion #2 crossed to w1118 labeled as 60-2-w1118 (v) Mhc-Gal4 crossed to UAS-hsp60 insertion #1 or #2, labeled as Mhc-60-1 and Mhc-60-2 respectively. n=4, error bars denote s.e.m; and * = p<0.05, ** = p<0.01 and *** = p<0.001.

(F) Climbing ability of flies expressing Hsp60 or Hsp60C under the control of the Mhc-Gal4 driver. Data shown is for three independent experiments, and is expressed as the mean ± s.e.m. The starting number of flies for each genotype in each experiment = 100, and * = p<0.05, ** = p<0.01 and *** = p<0.001. p values shown refer to comparisons between the particular genotype and Mhc-Gal4/w¹¹¹⁸ flies (deep blue columns). Climbing ability was not preserved when the Hsp60/60C transgenic flies were crossed to w1118 flies (not shown).

See Figure S4C and Table S6R.