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Date of Award

Spring 2007

Document Type

Restricted Thesis: Campus only access

Degree Name

Bachelor of Science



First Advisor

Dr. John M. Warrick


Spinocerebellar ataicia type III (SCA-3), commonly known as Machado Joseph Disease, is an inherited, neurodegenerative disease. This disease is caused by the expansion of the nucleotide sequence, CAG, into the DNA structure (Warrick et al 1999). Each CAG sequence corresponds to the amino acid glutamine, resulting in an expanded glutarnine chain in the primary structure of the protein (Khare et al 2005). This expansion may disrupt, thus compromising, the normal function of the protein (Khare et al 2005). The insertion of glutamine residues into protein structure is not in itself enough to causes pathogenesis, as glutamine is an essential amino acid that has multiple functions in normal, healthy proteins. Research as shown that there is a threshold for toxicity, and proteins possessing more than that number of glutarnines have this toxic gain of function; this threshold level has been found to be between 35-40 glutamine residues (Khare et al 2005), with longer chains of glutamines leading to faster and mqre severe disease progression (Bonini and Fortini 2003).