In an effort to develop a drug to combat obesity, researchers have long sought to find a gene that controls weight. The discovery of the defective agouti gene, which can cause mice to swell up to three times their normal size, and the human fat-regulating gene leptin heralded a new era in body weight research. But a pill to combat obesity has remained tantalizingly beyond reach. Scientists may now be one step closer to developing therapies to regulate the genetic factors that play a role in obesity, following the discovery by Stanford researchers of another mouse gene involved in appetite and activity.
Mice lacking the newly discovered mahogany gene eat more and exercise more than normal mice.
At this stage, the researchers are not sure which comes first if overeating causes the mice's increased activity, if overactivity causes excessive eating, or even if the two behaviors are dependent on one another. It may be that they just happen separately but concurrently, said Barsh. The mystery deepens when the role of the mahogany gene's human counterpart is considered. A large part of the protein made by the mouse mahogany gene has been found to be 93 percent identical to a human protein called attractin, which was recently discovered by Jonathan Duke-Cohan and colleagues at Boston's Dana Farber Cancer Institute. The human protein is produced by activated T cells and is thought to stimulate attraction between cells of the immune system.