Alpha-Synuclein (AS) is a protein that is expressed most abundantly in the brain and other nerve tissues. More is known about the dysfunction of AS than the normal function. (1) This protein is associated with up to 11 different gene mutations that can adversely affect the conformation of the protein and proteins it may interact with.(6) Genetic or environmental factors can cause AS to aggregate and form buildups of the protein in neuronal cell bodies, away from the cell membrane; the aggregations of AS are called Lewy bodies. These structures were originally thought to be the cause of the death of dopaminergic neurons characteristic of Alzheimer’s Disease. (6,11,13) More recent research suggests, however, that the pathogenic form of the protein is the five part oligomer that, when associated with cell membranes, forms a pore-like structure; the going theory is that the Lewy Bodies are the cell’s defense mechanism against the pore-like oligomer.(14)
Specific Aim 1: This research will seek to identify an RNA aptamer with an affinity for the functional monomer of the AS protein, Figure 1. Single stranded RNA aptamers will be selected from a pool of random RNA sequences through repeated rounds of selection in a "process of elimination" type assay. An aptamer could functionally inhibit the monomer, preventing it from forming the toxic oligomer. Adding a fluorescent tag to the aptamer would prove useful for helping to further research of how and why the protein misfolds to form the Lewy bodies by allowing for direct observation.(4)
Specific Aim 2: It would be doubly useful to perform simultaneous rounds of selection against samples of the aggregate forms of AS (see Figure 1) including negative selections in order to increase the in vivo affinity and specificity of the respective aptamers. An aptamer that could bind to the aggregated Lewy bodies would be integral in early diagnostics by adding visible tags to the aptamer.(8) Since Lewy body formation is also often associated with decreased proteosome effectiveness, an aptamer that was tagged with ubiquitin could be used in therapeutics to aid the cell in proper destruction of the aggregations. (5, 9,12)
This protein can be purchased through the GenWay website for $165 for every .1mg. The catalog number is 10-663-45667.