Taste Tests

January 31, 2007
Boy with lollipop

Patet Hince

A gene that controls the development of taste buds has been discovered by scientists at Duke Medical Center. The gene, SOX2, stimulates stem cells on the surface of the embryonic tongue and in the back of the mouth to transform into taste buds, according to the researchers.

"Not only did we find that SOX2 is crucial for the development of taste buds, but we showed that the amount of SOX2 is just as important," says Brigid Hogan, chair of the medical center's department of cell biology and senior member of the research team. "If there isn't enough SOX2 present, or if there is too much, the stem cells will not turn into taste buds." The researchers made their discovery in mice, but they believe the same process occurs in humans. Their findings were published in the journal Genes and Development.

According to the researchers, the findings will help scientists better understand how the behavior of certain stem cells is controlled. Stem cells are immature cells that can develop into several different cell types, depending on the biochemical instructions they receive. The SOX2 gene is already known to play a key role in controlling whether embryonic stem cells remain undifferentiated or whether stem cells in the brain, eye, and inner ear differentiate into specialized nerve cells.

Taste-bud cells, much like skin cells, continually slough off and are replaced by new ones. So the new findings not only provide insights into the interactions between SOX2 and tongue stem cells during embryonic development, but also into how stem cells continue to operate in adults.

Hogan says the team's findings were entirely serendipitous. "We were studying the role of SOX2 in the development of the lung, esophagus, and the gut in embryonic mice," she says. "We were quite surprised when we accidentally found the gene's role to be so pronounced in the developing tongue."