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P A Y W A L L E D S O U R C E : PNAS
Significance
Aging is associated with a myriad of changes at all levels of organization of an organism. However, how it affects protein synthesis, a major metabolic activity of the cell, is unknown. We discovered deregulation of protein synthesis and ribosome biogenesis machinery specifically at the translational level with age. Moreover, ribosomes were depleted in the vicinity of start codons and increased near stop codons. These findings reveal systematic, multilevel deregulation in gene expression and protein synthesis, showing how this major cellular process declines with age.
Abstract
Protein synthesis represents a major metabolic activity of the cell. However, how it is affected by aging and how this in turn impacts cell function remains largely unexplored. To address this question, herein we characterized age-related changes in both the transcriptome and translatome of mouse tissues over the entire life span. We showed that the transcriptome changes govern those in the translatome and are associated with altered expression of genes involved in inflammation, extracellular matrix, and lipid metabolism. We also identified genes that may serve as candidate biomarkers of aging. At the translational level, we uncovered sustained down-regulation of a set of 5′-terminal oligopyrimidine (5′-TOP) transcripts encoding protein synthesis and ribosome biogenesis machinery and regulated by the mTOR pathway. For many of them, ribosome occupancy dropped twofold or even more. Moreover, with age, ribosome coverage gradually decreased in the vicinity of start codons and increased near stop codons, revealing complex age-related changes in the translation process. Taken together, our results reveal systematic and multidimensional deregulation of protein synthesis, showing how this major cellular process declines with age.
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Edited by Engadin, 03 July 2020 - 05:25 PM.
