Figure 1. miRNA profiling during Drosophila adult life. (A) Heat-map of normalized expression values in young and aged male flies (50% of population dead). Flies living on three different food compositions were analyzed (LSLP, dietary restricted; HSHP, rich food; LSHP, food with an excess of protein over sugar). (B) Northern blot validation of expression changes identified in (A). Female flies were maintained on standard yeast-molasses-cornmeal growth medium, 28 d of age corresponds to a time point when about 50% of the population has died. The membrane was probed, stripped and re-probed sequentially for the miRNAs indicated on the right. The 30 nt long 2S rRNA served as a loading control. (C) Experiment analogous to (A) with transgenic male flies expressing miR-277 under the control of a strong, ubiquitous promotor. Downregulation of miR-277 was prevented, but other age-associated changes in miRNA-levels remain unperturbed. A common color scale was employed for (A and C).