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Breakefield Lab
The Breakefield laboratory uses molecular genetic techniques to elucidate the etiology of inherited neurologic diseases and to develop vectors which can deliver genes to the nervous system for therapeutic purposes.
A plasmid-based amplicon vector has been developed for non-toxic gene delivery to cells. This vector, which uses the herpes virion for gene delivery, can carry large transgenes (up to 150 kb), and has been modified to include elements that promote episomal retention or integration into the host cell genome. Further constructions are underway to incorporate inducible and cell-specific promoters, to promote homologous recombination, and to convert cells to vector-producing cells. These vectors are being tested in transgenic mouse models of ataxia telangiectasia, hormone deficiency states, neurofibromatosis and tuberous sclerosis to try to achieve correction of genetic defects. Vectors are also being tested for therapy of experimental brain tumors and lysosomal storage disorders. Work is underway to expand the range of gene delivery in vivo using migratory neuroprecursor cells, as well as to visualize transgene expression and neuronal circuitry in animals with MRI, near infrared imaging and bioluminescence.
Through positional cloning efforts this laboratory has identified the gene responsible for a severe form of dystonia characterized by contracted posturing of the limbs and torso starting in childhood. The responsible protein, torsinA, has homology to the AAA+ class of chaperone proteins, which have a variety of functions including protection from cellular stress and vesicle transport/fusion. Immunocytochemistry, yeast two-hybrid screens, and inducible cell expression are being used to study the ER localization and function of this protein, as well as the nature of whorled membrane inclusions formed by the dominant-negative mutant protein. TorsinA appears to be a chaperone protein involved in membrane trafficking.