Previous research at Stanford University Medical Center and the University of Minnesota had found a deficiency in corticocosteroid regulation after exposure to mild stress in children with Fragile X syndrome. A reduced level of the glucocorticoid receptor, in the absence of the FMRP protein, Weiler said, would plausibly affect corticorsteroid feedback mechanisms, leading to prolonged levels of anxiety in Fragile X patients.
"We have shown that a particular messenger RNA -- the product of a particular gene which encodes the glucocorticoid receptor -- is bound to the Fragile X mental retardation protein, and it is differentially regulated in its expression in neurons of animals than can make FMRP versus animals that cannot," said Greenough, who holds a Swanlund Endowed Chair at Illinois. "In essence, we've shown that a major symptom of Fragile X syndrome is accounted for, in principle, by the binding of FMRP to the gene product, the messenger RNA that encodes this receptor."
The technique and protein-mRNA discoveries offer a new view of Fragile X syndrome and a potential approach to develop new treatments, said Weiler, an adjunct professor of psychology. "Fragile X up to now has been considered to involve a single missing protein, but it turns out that the protein involved is probably governing the production and localization of a group of sub proteins, making this a multigenic disease," she said.
"We are very pleased with this new methodology that Dr. Eberwine has developed," Weiler said, "because for the first time FMRP and its associated mRNAs for this subset of proteins have been localized in situ -- in an intact neuron -- rather than in homogenate brain tissue. So we feel that h
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Contact: Jim Barlow
b-james3@uiuc.edu
217-333-5802
University of Illinois at Urbana-Champaign
6-Feb-2003