Aggregation and Clearance of Mutant Huntingtin(RMI)

[unreadable] DESCRIPTION (provided by applicant): Accumulation and aggregation of mutant proteins are a common link across a wide array of neurodegenerative disorders. Recently, an exciting theme has emerged: if mutant protein accumulation is eliminated, symptomatic progression not only halts but also leads to recovery from disease. The first indication that neurodegenerative diseases are reversible comes from an inducible mouse model of the polyglutamine disorder Huntington's disease (HD). In the presence of expanded polyglutamine huntingtin, mice recapitulated HD-like symptoms. When mutant gene expression was abolished, not only did the aggregates disappear, the symptoms regressed. These findings signal that neurodegenerative diseases need no longer be considered a death sentence. Unfortunately, however, the pathway underlying clearance of these mutant proteins are not yet clear. We believe that screening a well-designed cell-based assay with a chemical compound library will allow us to not only further clarify which degradative pathway is important, but may also reveal new means by which these pathways can be activated. We have therefore designed a functional cell-based assay that monitors not only aggregation of mutant huntingtin protein, but also its clearance. To do so, we created a stable cell line that conditionally expresses the N-terminus of huntingtin protein with polyQ proteins of different polyQ lengths fused to variants of GFP. These cell lines permit high throughput confocal microscopy to examine the state of the expressed mutant protein in live cells. We hypothesize that by eliminating the accumulated protein we will bring about recovery of the neurodegenerative process, as shown in several animal models of the disease. [unreadable] [unreadable]