Investigations into the role of a dynein mutation in rescuing the defects observed in a transgenic mouse model of ALS

ALS is a form of motor neuron disease which strikes mainly in 40s-60s. Using the Mouse as a model system in combination with cellular and biochemical techniques, we wish to capitalise on our findings that have highlighted the ivolvement of a protein called dynein in this disease to determine how impairment of this protein delays the onset and progression of ALS. We will publish our data in scientific journals for other scientist, and present our results in national and international meetings as well as in the symposia and seminars held at regular basis at the Life Sciences and Medical Schools in The University of Sussex. The university has several strategies in place for the engagement of the general public in its research activities. These range from the publication of research findings on publicly available websites and newsletters as well as mechanisms for the release of information to the local and national press. In addition there are opportunities for the discussion of science policy and research with teachers and the general public during University open days and during visits to and from local schools. I appreciate the importance of the wider engagement of the public in science as a whole and will provide all support for the University?s efforts in these activities.

Amyotrophic lateral sclerosis (ALS) is a debilitating degenerative disorder of motor neurons in human. ALS is a fatal disease manifested by progressive muscle weakness, wasting and spasticity. It causes the death of over 100,000 individuals worldwide every year, mainly striking in mid-life (50s - 60s) and killing within 1-5 years following diagnosis. There is no cure for ALS. About 10% of all cases are familial, mostly with a dominant pattern of inheritance. Of these the cause for only ~15-20% has been identified as mutations in the gene coding for superoxide dismutase 1 (SOD1). SOD1G93A transgenic mice carrying a human form of mutant SOD1 succumb to an ALS-like disease which has the hallmarks of ALS in humans.

In the Legs at Odd Angles (Loa) mouse model, we showed that mutations in dynein, a motor protein responsible for retrograde axonal transport, impair fast axonal transport in homozygous Loa and lead to motor neuron death. Intriguingly, in our recent study where we crossed Loa with SOD1G93A transgenic mice, we observed that the Loa mutation in its heterozygous state rescues the retrograde transport defect present in SOD1G93A motor neurons and delays disease onset and progression in Loa/SOD1G93A double mutants. The mechanisms of this rescue and amelioration of the disease is unclear.

In this proposal our objectives are: 1) determining protein interactions between SOD1 and components of dynein, by epitope tagging of SOD1 and performing immunoprecipitation assays on extracts from primary motor neurons and NSC34 motor-neuron-like cells containing the tagged SOD1 proteins; 2) identifying components of the pathways that contribute to the amelioration of the disease in the double mutants, by a global proteomics approach using Two-dimensional gel analysis. We will use our in-house state-of-the-art proteomics facilities in these studies. Functional analyses of the proteins identified in ?1? and ?2? will be followed to elucidate the molecular mechanisms of rescued SOD1G93A phenotype by Loa mutation. This study may lead to identification of target proteins for therapeutic intervention in ALS patients.