Loss of gene leads to protein splicing and buildup of toxic proteins ...( JACKSONVILLE Fla. -- Researchers at ...),Health

JACKSONVILLE, Fla. -- Researchers at Mayo Clinic in Jacksonville have discovered how loss of a gene can lead to accumulation of toxic proteins in the brain, resulting in a common dementia, and they say this mechanism may be important in a number of age-related neurological disorders.

In the Sept. 26 issue of the Journal of Neuroscience, the scientists demonstrate that absence of a gene known as progranulin leads to errant splicing of a protein that usually operates within the nucleus of a nerve cell (neuron). When cut these proteins move into the body of the cell, and begin to stick together and form a thicket that grows, eventually disrupting the normal functioning of the neuron, the researchers say.

Clumps of this protein, TDP-43, have been found in a number of older age dementias, including Alzheimers Disease (AD), Frontal Temporal Dementia (FTD), and in amyotrophic lateral sclerosis (ALS).

Not only does the study potentially explain why TDP-43 pathology is present in a number of neurodegenerative diseases, it also offers new research routes to take in looking for beneficial treatments, says the studys lead investigator, Leonard Petrucelli, Ph.D. Our work opens opportunities on possible future therapeutic applications, from approaches to novel drug discovery to the continued exploration of cell survival systems, he says.

Mayo investigators filled in this piece of the dementia puzzle by exploring possible connections between two recent ground-breaking discoveries. In July, 2006, Mayo researchers reported in Nature that a form of FTD not caused by tau accumulation in neurons was due to mutations in the progranulin gene. Progranulin produces a protein that helps neurons survive, and so far, the research group has found more than 40 different mutations in the gene can directly cause FTD.

The second study, reported in October, 2006, in Science by researchers at the University of Pennsylvania School of Medicine, found
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