A Popular Science View of Recent Thinking on DNA Damage as a Cause of Aging

There are presently two views of the way in which stochastic DNA damage can contribute to aging. Most DNA damage occurs in inactive genes in cells that will not replicate many more times, and thus cannot possibly produce systemic consequences throughout large regions of the body. The first argument for a way in which random DNA damage can produce a broader effect is via somatic mosaicism, in which mutational damage occurs in stem cells, allowing those mutations to spread throughout tissue over time. It is unclear as to how to measure the contribution of this process to age-related loss of function, however, and its contribution to aspects of aging other than cancer risk remains debated. The second view focuses on changes in gene expression that can result from the complex processes of DNA damage and DNA repair. The actions of DNA repair in particular can alter the balance of various factors in the cell nucleus, leading to altered epigenetic marks on the genome, altered nuclear genome structure, and consequently altered transcription of DNA to RNA. This can link DNA damage even in inactive genes to broad consequences for cell behavior. Today's popular science article provides a readable overview of one such issue noted in older animals, dysfunction in the RNA polymerase II that moves along the genome to read DNA and assemble molecules to form RNA. With age, this production of RNA becomes slower and more prone to failure, changing the landscape of gene expression and thu...
Source: Fight Aging! - Category: Research Authors: Tags: Medicine, Biotech, Research Source Type: blogs