Yeast moms sacrifice self to nourish kids
A mother's willingness to sacrifice her own health and safety for the sake of her children is a common narrative across cultures but new research has showed that it is also done by yeast moms.
The University of California, San Francisco scientists found that the yeast Saccharomyces cerevisiae ensured the health of its budding offspring by pushing essential internal structures known as mitochondria into them.
In the new paper, the UCSF team describes how yeast cells ferry just the right amount of mitochondria along a network of protein tracks and molecular motors into the young yeastlings, which bud off their mother like mini-me's.
But what surprised the researchers, led by Wallace Marshall, PhD, UCSF associate professor of biochemistry and biophysics and UCSF postdoc Susanne Rafelski, PhD, was how yeast mothers continued to give generous amounts of their mitochondria to their offspring even when it meant hastening their own death.
"The mom will pump in as many as [the bud] needs," Marshall said.
"The bud gets more and more as it grows, and mom doesn't get any more," he said.
Working with yeast, the UCSF team developed sophisticated microscope and computer techniques that allowed them to track the movement of mitochondria within cells.
What they found instead was that the yeast mothers gave a consistent amount of mitochondria to their offspring at each generation, and so over time they had fewer and fewer of the organelles themselves.
Mutant forms of yeast, which were much more stingy in giving up their mitochondria, lived much longer.
The study has been published in the journal Science.