Tri-methylation of lysine 36 on H3 restricts gene expression variation during aging and impacts lifespan

Functional data indicate that specific histone modification enzymes can be key to longevity in Caenorhabditis elegans, but epigenetic mechanisms of lifespan regulation are not well understood. In this study, we profiled the genome-wide pattern of tri-methylation of lysine 36 on histone 3 (H3K36me3) in the somatic cells of young and old C. elegans. We revealed a new role of H3K36me3 in maintaining gene expression stability through aging with important consequence on longevity. We found that genes with dramatic expression change during aging are marked with low or even undetectable levels of H3K36me3 in their gene-bodies, irrespective of their corresponding mRNA abundance. Importantly, inactivation of the methyltransferase met-1 resulted in a decrease in global H3K36me3 marks, an increase in mRNA expression change with age, and a shortened lifespan, suggesting a causative role of the H3K36me3 marking in modulating age-dependent gene expression stability and longevity.