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Thursday, December 2, 2010

Color-coding cell parts

Imre Berger and Philipp Berger from the Paul Scherrer Institut, Switzerland have developed a way to label mammalian cells with an assortment of fluorescent markers. Single markers have been used in mammalian cells before, but this breakthrough represents the first time multiple markers have been used at once.

To visually label a cell part, a fluorophore, or fluorescent molecule, is constructed with a binding site that will attach it to a particular target molecule. For example, a fluorescent marker might specifically bind to a mitochondrial protein or to a component of the cell wall. When viewed under the right conditions, the mitochondria or other components will fluoresce, making them stand out.

Most markers must be genetically inserted into the cells so that the cells manufacture the label and attach it to the target from the inside. In the past, fluorescent label genes have been introduced into cells one at a time. Berger and Berger’s innovation was in developing a way to introduce multiple genes at one go. Imre Berger pioneered the technique of using a single vector to insert up to 15 different genes in insect cells.

You can watch a clip of the labeled cells below. Under normal lighting, the cells are colorless, but under proper lighting, the various markers become visible.

Blue: nuclei

Yellow: tubulin (a component of the cell’s scaffolding)

Red: mitochondria

Teal: endosome (internal vesicle) membranes

Purple: other membrane structures.

The scientists call their new labeling method ‘MultiLabel’, and expect it to have applications in drug screening and testing as well as in cellular studies.