MicroRNAs induced during response to stress in C. elegans

To understand how microRNAs are involved in stress response, we examined their expression changes in C. elegans animals that were exposed to stress conditions, including heat shock, oxidation, hypoxia and starvation. Overall design: Total RNAs were purified from young adult animals that were exposed to each stress, and used for cDNA library preparation for small RNAs. In this experiment, spe-9(hc88), a temperature sensitive sterile mutant, that were cultured at 23dC, was used in order to avoid the effect from developing embryos. Stress conditions we examined include: Heat shock (32°C, 6 hrs), Recovery from heat shock (6 hrs recovery at 23°C after heat shock treatment at 32°C for 6 hrs), Hypoxia (0.01%, 6 hrs), Oxidation (Juglone 750 µM, 6 hrs), Starvation (complete food deprivation, 12 hrs). In addition to these stress conditions, RNAs were prepared from normally cultured, untreated animals at three time points, 0 hr (baseline), 6 hrs (as controls for heat shock, hypoxia and oxidation) and 12 hrs (as controls for heat shock recovery and starvation) after starting stress exposure. These cDNA libraries established were sequenced with Illumina Genome Analyzer II.