http://news.excite.com/news/r/011120/10/health-genes

Tue, Nov 20 10:19 AM EST

By Merritt McKinney

NEW YORK (Reuters Health) - Scientists have discovered a mutant protein in mice that slows down the degeneration of nerve fibers after injury.

Although the same protective protein is unlikely to be found in humans, studying the protein in mice may lead to ways to protect nerve fibers in people, one of the study's authors told Reuters Health.

Normally, axons, the long connections between neurons, degenerate within 24 to 48 hours of being cut. But in a particular strain of genetically engineered mice, this degeneration goes into slow motion, taking several weeks instead of a few days.

Why axons are protected in these mice has been unknown, but now a team led by Dr. Michael P. Coleman at the Institute for Genetics in Cologne, Germany, has identified a gene in the mice that contains the instruction for an axon-protecting protein.

"We report a mutant gene that protects axons from injury and disease in mice," Coleman told Reuters Health. The findings will be published in the December issue of the journal Nature Neuroscience, but were released early in the online version of the journal.

Axons can be damaged by physical trauma, such as brain and spinal cord injuries, as well as by some drugs used to treat cancer and AIDS, according to Coleman. Metabolic disorders such as diabetes and diseases including multiple sclerosis also harm axons, he said.

Coleman added that axon degeneration is suspected of being involved in many other degenerative neurological diseases including Alzheimer's and Parkinson's, but he said it is too soon to know for sure.

Most research on neurons has focused on the cell bodies, which are thought to be the controlling part of the neuron, Coleman explained. In contrast, much less is known about axons, he said.

Coleman pointed out that it is "highly unlikely" that the gene mutation that protects axons in mice is present in people. "However, it is very likely that related mechanisms control axon degeneration in humans," he said.

If future research uncovers how the gene protects mouse axons, it may be possible to develop ways to intervene in human conditions that affect axons, he said.

The research opens up the possibility of keeping axon degeneration from happening in the first place, Coleman noted.

"We have identified a gene that can keep sick axons alive. This is an alternative to the more popular idea of helping axons to regenerate after they have been lost," he said.

"Prevention is better than the cure," he stated.

SOURCE: Nature Neuroscience online 2001;10.1038/nn770.
 

© 2001 Reuters Limited