Abstract: The present invention concerns the use of particular RNA sequences as a medicament. More precisely, it concerns the use of small nucleolar RNAs (snoRNAs) which the inventor has shown to be involved in the mechanisms of aging. The snoRNAs of the invention can be used in particular to increase the stress resistance of a subject and to fight against the harmful effects of aging, typically for preventing or treating a degenerative disease, a laminopathy, diabetes, obesity or a cancer and, more generally, to prolong the lifespan of a subject. The snoRNAs of the invention can also be used in the treatment of infertility. The invention further relates to vectors, cells, transgenic animals and compositions capable of expressing an snoRNA of the invention, and methods using any of the above products of the invention as a tool for identification of a molecule active in the prevention or treatment of a pathology, abnormality or disorder linked to a mechanism of aging.