Carnegie Institution scientists in the United States say that a gene, named scrawny, seems to play a significant role in keeping a variety of stem cells in their undifferentiated state.
Writing about their observations in the journal Science, the researchers said that understanding how stem cells maintain their potency has implications both the knowledge of basic biology and for medical applications.
"Our tissues and indeed our very lives depend on the continuous functioning of stem cells. Yet we know little about the genes and molecular pathways that keep stem cells from turning into regular tissue cells-a process known as differentiation," says Allan C. Spradling, director of the Carnegie Institution's Department of Embryology.
Along with his colleagues Michael Buszczak and Shelley Paterno, Spradling has found that the fruit fly gene scrawny-so named due to the appearance of mutant adult flies-modifies a specific chromosomal protein, known as histone H2B, which is used by cells to package DNA into chromosomes.
The researchers say that scrawny can by controlling the proteins that wrap the genes, scrawny can silence genes that would otherwise cause a generalized cell to differentiate into a specific type of cell, such as a skin or intestinal cell.
During the study, the researchers observed that mutant flies without functioning copies of the scrawny prematurely lost their stem cells in reproductive tissue, skin, and intestinal tissue.
Stem cells function as a repair system for the body, and maintain healthy tissues and organs by producing new cells to replenish dying cells and rebuild damaged tissues.
"Losing stem cells represents the cellular equivalent of eating the seed corn," says Spradling.
He adds that the results of the study are an important step forward in stem cell research because genes that may carry out the same functions as scrawny are known to be present in all multicellular organisms, including humans.
"This new understanding of the role played by scrawny may make it easier to expand stem cell populations in culture, and to direct stem cell differentiation in desired directions," the researcher says.