A cellular secret to long life
Longevity may depend in part on neatly spooling DNA
Just as proper storage keeps a loaf fresh longer, adequate packaging may be a key to cellular longevity, reports a study of the organisms that make bread rise.
New research on aging in baker’s yeast suggests that proper packaging of DNA can halt aging and lead to longer life. The study, published September 10 in Molecular Cell, shows that a decline in levels of DNA-packaging proteins called histones is partially responsible for aging, and that making more of the proteins can extend the life-span of yeast.
Aging has many different causes, says Jessica Tyler, a molecular biologist at the University of Texas MD Anderson Cancer Center in Houston. Now, Tyler and her colleagues think they have uncovered yet another way cells age – by losing histones.
Histones are important proteins that form a spool upon which DNA is wound. This spooling allows yards of DNA to fit inside a cell and also helps control how genes are turned on and off (SN: 5/24/10, p.14). Tight winding helps keeps genes off, while loosening the packaging allows genes to be turned on.
As yeast cells age they make fewer histone proteins, Tyler’s team found. In order to determine whether losing histones is a cause of aging, the researchers studied yeast lacking a protein called Asf1. Without the protein, genes encoding histones don’t get turned on as often, and fewer histones are made.