A Powerful Tool
In the basic technique, a new gene can be added to cells within a larger DNA vector that also includes the genetic sequences for ChBD and GFP. The ChBD molecule will be produced in such a way that it ends up being held on the outer surface of its host cell's plasma membraneand the GFP molecule will sit just inside the membrane. The GFP serves as a visual beacon, while the ChBD serves as a handy gripping point for cell selection.
After exposing a culture of test cells to this experimental ChBD-containing vector, the scientists was able to see, via the GFP tags, which cells were expressing them, and was able to select them out easily, with high sensitivity, using magnetic beads coated with chitin. "This is a relatively easy benchtop method," Peng said. Importantly, these selected cells could produce progeny cells that seemed normal and healthy.
Because the ChBD marker, in the vector, is produced in a way that anchors it to a cell's membrane, it also can serve as a powerful tool for selecting just the membrane fraction of a sample of cellular material. Peng and his colleagues demonstrated this using chitin beads to quickly isolate a pure fraction of membrane material from ChBD-marked test cells.
Cellulase enzymes, which break down the ubiquitous plant compound cellulose, also have a high-affinity cellulase-binding domain, which can be employed in the same way as the ChBD.
The scientists exp
|Contact: Mika Ono|
Scripps Research Institute