Study of the Regulation of Aggregates Formation by ALS associated SOD1 Mutations Using Drosophila. Michael Mccarthy^1,2,3,4, Dongsheng Chen^1,2,4, Zhihua Zhen^1,2,4, Antonio Tito^1,2,3,4, Zhen Xu^1,2,4, Yanning Rui^1,2,4, Sheng Zhang^1,2,3,4. 1) Center for Degenerative and Metabolic Disorders, Houston, TX; 2) Institute of Molecular Medicine, 1825 Pressler St., Houston, TX; 3) GSBS, Houston, TX; 4) UT-Houston, Houston, Texas.

   The presence of protein aggregates is a common pathological feature of most neurodegenerative disorders such as Amyotrophic Lateral Sclerosis (ALS). While it is still controversial whether or not aggregates is deleterious or protective, understanding the cellular pathways that regulate aggregates formation will help elucidate the pathogenic mechanisms underlying these devastating diseases and facilitate the search for their effective treatment. ALS, also known as Lou Gehrigs disease, predominantly affects motor neurons. Mutations in Superoxide Dismutase 1 (SOD1), which are linked to about 20% of familial ALS (fALS), are believed to lead to a gain of toxicity. Among the common fALS mutations, neither A4V nor G93A interferes with SOD1s normal cellular function, while G85R does have an effect and also is aggressive at forming aggregates. To identify regulators of aggregates formation associated with SOD1 mutations, I plan to establish both cell- and animal-based models for ALS in Drosophila. To facilitate convenient visualization of aggregates, I will co-express mutant SOD1 (A4V, G85R, or G93A) labeled with eGFP fluorescent tag together with wildtype (wt) SOD1 labeled with mCherry tag, the latter serves as an internal control for the level of protein expression and for confirming the mutant SOD1-specific aggregates formation. To date, I have engineered all the planned SOD1 tagging constructs both for copper-inducible expression in cultured Drosophila cells and for establishing transgenic fly lines. I am characterizing the established SOD1 transgenic fly lines for potential formation of aggregates and neuronal toxicity. Establishment of these new ALS models will help uncover the molecular networks that control SOD1-associated aggregates formation, potentially providing targets for effective therapeutic intervention.