Reproductive activity triggers accelerated male mortality and decreases lifespan: genetic and gene expression determinants in Drosophila.

Fly strain y[1]; bw[1]; e[4]; ci[1] ey[R] was obtained from the Bloomington Stock Center. Flies were reared in incubators at 25°C, 65% of relative humidity, and photoperiod of 12 hours. For gene expression analyses virgin male flies were aged for 33 days, and allowed to mate for 48h with young virgin female flies. After exposure, they were flash-frozen in liquid nitrogen. Four replicas of each sample were collected and stored at -80°C. Total RNA was extracted from whole flies using TRIzol (Life Technologies). The synthesis of cDNA and its labeling with fluorescent dyes (Cy3 and Cy5) as well as hybridization reactions were carried out using 3DNA protocols and reagents (Genisphere). Slides were scanned using Axon 400B scanner (Axon Instruments) and GenePix Pro 6.0 software. Foreground fluorescence of dye intensities was normalized by the Loess method in Bioconductor / Limma. Dye "swaps," loop design.