rRNA degradation is strongly correlated with ROS levels and is connected with oxidative stress response and apoptosis pathways Treatment with oxidative agents and apoptotic stimuli generate elevated levels of ROS in the cell. To test whether there is a direct link between RNA fragmentation and ROS, a potent ROS scavenger, L-ascorbic acid (vitamin C), was used (44) . The presence of 10mM ascorbic acid prior to treatment with standard doses of H 2 O 2 almost totally abrogated degradation of the 25S rRNA ( Figure 4A ). In addition, the ectopic expression of murine Bcl-x L protein of the anti-apoptotic mammalian Bcl-2 family, known to have a protective effect against ROS in yeast (45, 46) , also strongly safeguarded the 25S rRNA from rapid degradation by H 2 O 2 ( Figure 4B ). In contrast, expression of the mammalian pro-apoptotic Bax protein that increases ROS level (36, 47) , additionally enhanced the degradation phenotype ( Figure 4C ). This confirms the direct correlation between the production of ROS and the fate of cellular nucleic acids, leading not only to DNA but also rRNA damage and destruction of ribosomes.