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.

The researchers found that intestinal stem cells make important decisions about their fate by communicating directly with their daughter cells, instructing them to become one of two possible cell types. The studies bring researchers a bit closer to understanding how adult stem cells decide to make the cell type that best meets the current needs of the organism.

Embryology director and study co-author Allan Spradling says that stem cells can participate actively in determining what type of cell their daughters will become right at the moment of stem cell division, . 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.

As embryonic stem cells can become any cell in the body, they 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.

Link [www.hhmi.org/news/spradling20070215.html]