19 June 1998
Mellow Mice Chill Out For Science
First there was Mighty Mouse - and now comes Mellow Mouse, the coolest, calmest rodent ever to don a pair of sunglasses. Created by genetic engineers at Michigan State University, he's completely unflappable, and may help scientists get to grips with the mechanisms of stress management.
As reported in the June issue of Neuron, the key to unlocking the chill factor in mice is to "knock out" a gene that triggers anxiety. Reaction to stress - in both animals and humans - is mediated by a corticotropin-releasing factor receptor known as CRFR1 in the central nervous system. Take out the gene that produces CRFR1, and voila: relaxed rodents.
"These mice are mellow," says George Smith, assistant professor of animal science at MSU and a leading player in the project. "They don't get excited about anything."
To prove it he placed regular mice in a brightly lit clear tube, and watched as they fretted and stressed.
Mellow Mice in the same situation, however, felt secure and relaxed enough to explore their surroundings at a leisurely pace. Only a lack of deck chairs kept them from chilling out completely.
Scientists now hope these genetically engineered 'knock out' mice will help them develop new treatments and medications for stress-related disorders.
"Knock out mice are a valuable tool to tell how the body works," says Smith. "Hundreds of lines of knock out mice, each carrying a deletion of a single gene, have been generated by scientists in recent years, resulting in an explosion of information important to the biomedical community. Information obtained from knock out mice will help form the basis for many of the remarkable advances in treatment of genetic disease, cancer and neurological disorders awaiting us in the future."