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Thu Apr 4, 3:04 PM ET
By Christopher Doering
WASHINGTON (Reuters) - A pair of genes required for proper development of the brain have some surprising qualities that may help scientists find new ways to treat brain tumors and a variety of other diseases, researchers said on Thursday.
Mice bred to lack one or both of the Olig genes failed to develop motor neurons needed to control muscle movement and were completely paralyzed, according to the report in the April issue of the journal Cell.
"Many of the genes required to develop a normal brain are genes that when mutated or perturbed give rise to cancer of the brain," Charles Stiles, one of two senior authors, said in a telephone interview.
"The long-term goal was to characterize these genes so they might become attractive targets to develop...smart medicines that would selectively attack brain cancer cells," he added.
Stiles said "smart drugs" would focus on a brain tumor by targeting faulty Olig genes without harming nearby healthy cells.
About 17,000 people will develop cancer of the brain and nervous system in 2002 and 13,000 will die from the disease, according to American Cancer Society (news - web sites) estimates.
The nervous system, including the brain, is made up of three types of cells. Neurons, the most important but least numerous, send impulses that cause muscle movement. Several billion glial cells, or oligodendrocytes and astrocytes, support and feed the neurons.
"These two genes account for the formation of the cells that enable the vertebrate's brain to grow large and complex," Stiles said. "This is an important and crucial step in the study of brain development."
Oligodendrocytes, which grow when an Olig gene is activated, surround and protect the neuron in the form of myelin, a fatty material similar to rubber insulation that surrounds an electrical wire. This enables neurons to transmit messages at high speeds over long distances.
The loss of myelin leads to multiple sclerosis.
Stiles said the findings may allow researchers to uncover clues to this and other neurological diseases. The next step is to determine how Olig genes develop and how they function.
The researchers said they were surprised to find the close relationship between neurons and oligodendrocytes, which were previously believed to form independently of one another. Stiles said he now believes they come from the same precursor cell.
"If you look at previous thinking, there had been for a number of years a handful of specialists in the field that might have predicted this result...but couldn't prove it because there were no genetic buttons," said Stiles.
"It is fair to say that a large number of people in the area of neuron development will be surprised," he noted.