August 27, 2008
If you spent a few minutes clicking on Nature, Cell, or any other scientific journal, you’d draw two quick conclusions. The discovery of genes and their proteins have become commonplace. Secondly, many discoveries are so obscure in name and vague in biological function, at least at first, it’s hard to imagine where they will lead.
Take the case of the protein Ascl3, also called Sgn1. Working with mice in 2001, scientists identified this 174-amino-acid protein in the specialized duct cells of the salivary gland. They determined that the protein structurally belongs to a family of DNA-binding transcription factors that are known to participate in the process of tissue development and differentiation. Adding further weight to this finding, the scientists later reported that Ascl3 is barely detectable at birth in the salivary gland but increases as the tissue develops.
That’s where the data largely remained – in need of a scientific push. That push came recently when a team of NIDCR-supported scientists generated genetically modified mice that produced a fluorescently labeled version of the Ascl3 protein. Focusing on the developing sublingual salivary gland, the scientists monitored the cells that initially flashed the protein tag as well as their descendant cell lines. As published in the August issue of Developmental Biology, the scientists determined that the tags labeled a population of progenitor cells within the salivary glands that are capable of producing at least two cell lineages. The authors said the finding that Ascl3 is a marker for a population of progenitor cells is “a critical step in the progress toward identifying the source of cells that are responsible for salivary gland maintenance and regeneration.”