Working with fruit flies, researchers say that they discovered a new mechanism by which the abnormal protein in Huntington’s disease causes neurodegeneration.
Previous studies concentrated on the toxicity that the abnormal protein, huntingtin (htt), produces by forming cell-clogging aggregates in the nuclei of neurons. Most studies in animals, however, had not involved introducing the gene for full-length htt but only a fragment.
In current experiments, the scientists introduced the gene for full-length abnormal human htt into the fruit fly Drosophila and studied its early effects on neural function in the flies. They report that before the abnormal protein produced any toxic effects in the nuclei of neurons, it caused abnormally high transmission of neurotransmitters among neurons. The researchers also say that mutant htt caused neurodegeneration and degeneration in the flies’ motor ability.
The team discovered that they could suppress these abnormalities by introducing other mutations into the fly genome that either reduced neurotransmission or reduced the activity of calcium channels in the membranes of neurons.
The research was conducted by investigators from Baylor College of Medicine, the Howard Hughes Medical Institute, and the Buck Institute. The paper will be published in the January 10 issue of Neuron.