Fluorescent mouse can teach us about many diseases, drugs

Scientists from the UK and Australia have created a mouse that expresses a fluorescing 'biosensor' in every cell of its body, allowing diseased cells and drugs to be tracked and evaluated in real time and in three dimensions.

This biosensor mimics the action of a target molecule, in this case a protein known as Rac, which drives cell movement in many types of cancer. Rac behaves like a switch, oscillating on the molecular level between two states -- active or inactive. When Rac is active, the biosensor picks up chemical cues and glows blue. When Rac is inactive the biosensor glows yellow.

Using sophisticated imaging techniques, it is possible to follow Rac activation in any organ at any time, or watch moment-by-moment oscillation of Rac activity at the front or back of cells as they move in the body. This technology has been used to monitor Rac activity in many organs in response to drug treatment.

The biosensor is a single molecule probe named Raichu-Rac and was invented by Japanese scientist, Professor Miki Matsuda, in 2002.

Although many researchers have used Raichu-Rac since 2002, this is the first time a mouse has been genetically modified successfully to express the molecule throughout the body without affecting cell function. The mouse can be used to study any cancer type by crossing it with other models, limiting expression of Raichu-Rac to specific cell or tissue types. The mouse can also easily be adapted to study diseases other than cancer by expressing the biosensor in different disease models.