Although there is no evidence so far that rRNA damage during apoptotic conditions in yeast can directly initiate cell death by activating signalling pathways, it is tempting to speculate that this might be the case. Such signalling could be conveyed either by a critical decrease of the mature 25S rRNA or, alternatively, by the accumulation of degradation intermediates/products, which can function as signal molecules triggering a specific PCD pathway. In most cases, when ribosomal RNAs are depleted (e.g. in pre-rRNA processing mutants), rRNA degradation is conducted rapidly with no or little rRNA fragments detectable; however, lack of Lsm proteins has been reported to result in degradation of ribosomal RNAs with accumulation of unusual intermediates (70) . It is noteworthy that one apoptotic pathway that is linked with RNA metabolism is triggered by the defect in mRNA turnover caused by mutations in enzymes involved in 5 0 decapping, including components of Dcp1-2 and Lsm1-7 complexes (22) .