RNA polymerase III limits longevity downstream of TORC1

Three distinct RNA polymerases (Pols) transcribe different classes of genes in the eukaryotic nucleus1. Pol III is the essential, evolutionarily conserved enzyme that generates short, non-coding RNAs, including transfer RNAs (tRNAs) and 5S ribosomal RNA (rRNA)2. Historical focus on transcription of protein-coding genes has left the roles of Pol III in organismal physiology relatively unexplored. The prominent regulator of Pol III activity, Target of Rapamycin kinase Complex 1 (TORC1), is an important longevity determinant3, raising the question of Pol III’s involvement in ageing. Here we show that Pol III limits lifespan downstream of TORC1. We find that a reduction in Pol III extends chronological lifespan in yeast and organismal lifespan in worms and flies. Inhibiting Pol III activity in the adult worm or fly gut is sufficient to extend lifespan, and in flies, longevity can be achieved by Pol III inhibition specifically in the intestinal stem cells (ISCs). The longevity phenotype is associated with amelioration of age-related gut pathology and functional decline, dampened protein synthesis and increased tolerance of proteostatic stress. Importantly, Pol III acts downstream of TORC1 for lifespan and limiting Pol III activity in the adult gut achieves the full longevity benefit of systemic TORC1 inhibition. Hence, Pol III is a pivotal output of this key nutrient signalling network for longevity; Pol III’s growth-promoting, anabolic activity mediates the acceleration of ageing by TORC1. The evolutionary conservation of Pol III affirms its potential as a therapeutic target.