Stress can make you wish life had a pause button. Single-celled organisms like yeast actually have this option. Faced with a lack of food or other stressors, baker’s yeast can enter a “paused,” energy- and resource-conserving state called quiescence. In this paused state, in which DNA becomes more compact and most genes are shut off, yeast can live weeks or months without nutrients.
A key step in putting normal life on hold is cinching DNA into regular loops, according to new work by researchers at Fred Hutchinson Cancer Research Center, the University of Washington and the University of Massachusetts. In a study published today in the journal Molecular Cell, they identified the protein that yeast cells use to tighten DNA and shut off most genes.
The findings resolve a chicken-and-egg debate of the quiescence field: Does DNA become compact because most genes are shut off, or is DNA compaction a strategy to help turn genes off?
According to the new study, DNA compaction is a strategy, not a side effect. Genes get turned off because DNA compacts.
Some of our own cells, like the stem cells that feed our tissues, also temporarily enter this restful state under normal conditions. And evidence suggests that cancer cells may be able to resist anti-cancer drugs by becoming similarly dormant. A better understanding of this paused state could help scientists discover ways to awaken dormant tumor cells or sensitize them to anti-cancer drugs.
