Tho2-mediated escort of Nrd1 regulates gene expression for lifespan maintenance
The relationship between aging and RNA biogenesis and trafficking is attracting growing interest, yet the precise mechanisms are unknown. The THO complex is crucial for mRNA cotranscriptional maturation and export. Herein, we report that the THO complex is closely linked to maintaining a normal lifespan. Deficiencies in Hpr1 and Tho2, components of the THO complex, reduced replicative lifespan (RLS) and are linked to a novel Sir2-independent RLS control pathway. Although transcript sequestration in hpr1? or tho2? mutants was countered by exosome component Rrp6, loss of this failed to mitigate RLS defects in hpr1?. However, RLS impairment in tho2? was counteracted by Nrd1-specific mutants that interacted with Rrp6. This effect relied on the interaction of Nrd1, a transcriptional regulator of aging-related genes, including ribosome biogenesis or RNA metabolism genes, with RNA polymerase II. Nrd1 overexpression reduced RLS in a Tho2-dependent pathway. Intriguingly, THO2 deletion mirrored Nrd1 overexpression effects by inducing arbitrary Nrd1 chromatin binding. Taken together, these findings underscore the importance of Tho2-mediated Nrd1 escorting in maintaining a normal lifespan by transcriptional regulation of aging-related genes. Overall design: Chromatin immunoprecipiation sequencing (ChIP-seq) for recruitment of Nrd1 by tho2?