Baltimore, MD – From roundworm to human, most cells in an animal’s body ultimately come from stem cells. When one of these versatile, unspecialized cells divides, the resulting “daughter” cell receives instructions to differentiate into a specific cell type. In some cases this signal comes from other cells. But now, for the first time, researchers at the Carnegie Institution’s Department of Embryology have found a type of stem cell that directly determines the fate of its daughters.
The finding, reported in the January 25 online edition of the journal Science, could transform our basic understanding of stem cells by demonstrating that some tissues maintain themselves throughout life. It could also prove valuable in the fight against some cancers.
“We found that stem cells can participate actively in determining what type of cell their daughters will become right at the moment of stem cell division,” said Embryology director and study co-author Allan Spradling. “This suggests that tissue stem cells might not just be a source of new cells, but could actually be the ‘brains’ of the tissue—the cells that figure out what type of new cell is needed at any given moment.”
Because they truly can become any cell in the body, “embryonic” stem cells tend to receive a lot of attention. Yet “adult” stem cells remain in fully-developed organisms, where they replace specific cell types lost to age or disease. Spradling and postdoctoral researcher Benjamin Ohlstein performed the study using intestinal stem cells (ISCs), a type of adult stem cell in the fruit fly Drosophila melanogaster that they discovered only a year ago.