GLOWING MICE HELP STANFORD SCIENTISTS TRACK VIRUS GROWTH.

Byline: Associated Press

Scientists at Stanford University are injecting firefly genes into rats and mice, hoping to unlock the mysteries of how viruses spread through living organisms.

The firefly genes enable cells to make an enzyme called luciferase, which emits a pale yellowish green light when combined with a similarly named substance, luciferin. The result is mice that glow, allowing scientists to determine when and where other, disease-related, genes are active.

While the glow can't be seen with the naked eye, researchers use a $90,000 digital video camera that can detect extremely faint light. In a dark room, even organs deep in the body can emit enough light to be seen.

In one instance, scientists have injected some of the mice with the firefly genes combined with a gene normally found in HIV. By studying the conditions under which the HIV gene is active, new techniques to battle AIDS may be discovered.

The next step for researchers is to link the entire human immunodeficiency virus with the firefly gene, and to use it in mice in which scientists have introduced a human immune system. Then, drugs could be tested.

``To have an indicator light in these animals that tells you where and when the virus is replicating - in the living animal in real time - that would be amazing,'' said Christopher Contag, the director of bioluminescence research at Stanford's School of Medicine.

Contag said the rats and mice are the first living mammals in which the luciferase gene has been detected. A report on the work is published in this month's issue of the journal Photochemistry and Photobiology.