ing, and its transparency throughout its lifetime, which allows visualization of inclusions in living animals during aging. We expressed human a-synuclein fused to yellow fluorescent protein in the body wall muscle of C. elegans, where it, age-dependently, accumulated into inclusions. In old age these inclusions contained aggregated material, similar to human pathological inclusions. We used a genome-wide RNAi screen to identify genes and cellular processes involved in age-related asynuclein accumulation in inclusions. Results/Discussion To visually trace expression of a-synuclein, we expressed human a-synuclein fused to yellow fluorescent protein in C. elegans under control of the unc-54 promoter, which drives expression to the body wall muscle cells. Muscle expression rather than neuronal expression was chosen for several reasons. The unc-54 promoter is strong and muscle cells are large, allowing for visual detection of asynuclein expression and its subcellular localization. Furthermore, RNAi by feeding seems to work more efficiently in muscles than in neurons, which better allows for genome-wide RNAi screening. Finally, PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19861906 muscle expression has been used JW-55 site successfully to model protein-misfolding diseases and to identify modifier genes in previous studies. The a-synuclein-YFP chimaeric protein is recognized by an antibody specific for human a-synuclein and an antibody for YFP. YFP fused to human a-synuclein relocates to inclusions, which are visible as early as day 2 after hatching and increase in number and size during the animals’ aging up to late adulthood. As YFP alone remains diffusely localized throughout aging, this indicates that relocation of a-synuclein-YFP into foci is caused by intrinsic properties of the a-synuclein protein. One of the characteristics of late inclusions in the brains of Parkinson’s patients is the presence of electron-dense filamentous and granular protein material, which is typical for aggregated protein. To address whether a-synuclein was aggregated within the inclusions in our C. elegans model, we measured the mobility of the a-synuclein-YFP chimaera by fluorescence recovery after Modifiers of a-Syn Inclusion Formation Author Summary Parkinson’s disease is the second most common brain disorder of the elderly. It is thought to be caused by environmental and genetic factors. However, little is known about the genes and processes involved. Pathologically, Parkinson’s disease is recognized by inclusions in the brain that contain a disease-specific protein: alphasynuclein. We created a small animal model in which we could follow the formation of alpha-synuclein inclusions in living and aging animals. With a genomewide RNAi screen we identified 80 genes whose expression influences inclusion formation. These genes include evolutionarily conserved regulators of longevity, suggesting a link between inclusion formation and the molecular mechanism of aging. Our results offer a refined understanding of how Parkinson’s disease arises during aging and we identify processes and genes that may underlie an increased susceptibility for the disease, which is important for improving diagnostics and developing strategies for therapeutic intervention. photo bleaching . We observed two types of inclusions. One type contained mostly mobile material, whereas the other type contained immobilized material, similar to Q40- YFP aggregates, indicating aggregated protein, a characteristic of a-synuclein deposits in 
Parkinson’s disease.