DNA G-Quadruplexes in Epigenetic Cell Aging

Researchers here describe a G-quadruplex-related mechanism operating across diverse species that contributes to epigenetic change following cell replication, leading to the Hayflick limit on replication and subsequent cell death or cell senescence. G-quadruplexes form in telomeric regions at the ends of chromosomes, and their contributions to genomic structure, epigenetics, and aging are far from fully understood. Insofar as the mechanism described in this paper is operating in organismal aging, it is worth bearing in mind that aging is accompanied by a reduction in stem cell activity, meaning a reduced supply of replacement somatic cells for tissues. Thus the average somatic cell in a tissue starts to be one that is more cycles of replication removed from the original daughter somatic cell created by a stem cell, and will be more affected by any replication-related mechanism. Perhaps the more interesting result is the connection between this mechanism and a number of accelerated aging conditions, including Werner syndrome, in which mutations lead to an impairment of G-quadruplex removal. This implies that cell replication in affected individuals produces greater dysfunction than usual, leading to more cellular senescence and faster aging. How cell replication ultimately results in aging and the Hayflick limit are not fully understood. Here we show that clock-like accumulation of DNA G-quadruplexes (G4s) throughout cell replication drives conserved agin...
Source: Fight Aging! - Category: Research Authors: Tags: Daily News Source Type: blogs