Characterization of the interaction between a stable G-quartet forming oligonucleotide and huntingtin with an expanded poly-glutamine region
Author(s) | Yerkes, Sarah | |
Date Accessioned | 2010-08-05T21:46:24Z | |
Date Available | 2010-08-05T21:46:24Z | |
Publication Date | 2009 | |
Abstract | Huntington’s Disease is a progressive neurodegenerative disorder that is inherited in an autosomal dominant fashion. The disease is the result of an expanded CAG repeat in exon 1 of the HD gene which encodes an elongated poly-glutamine tract in the mutant form of the protein, huntingtin. The expanded poly-glutamine region causes the mutant protein to mis-fold and oligomerize, initiating a complex aggregation process. Disease pathogenesis is linked to the formation of these intracellular aggregates. It has been proposed that the aggregates themselves are toxic due to their physical presence which may block intracellular trafficking and signaling processes. A concurrent possibility is the sequestration of important proteins such as transcription factors during the aggregation process, disrupting their function resulting in cellular stress and death. In addition, the mechanistic steps that lead to aggregate formation may be central to HD pathology. A viable approach for HD therapeutics is to block the aggregation process of mutant huntingtin. It has been previously reported that guanosine rich oligonucleotides(ODN) that fold into a G-quartet formation are effective inhibitors of the aggregation process of a huntingtin protein fragment with an elongated polyglutatmine tract, Htt 1-171 (Q58)(Skogen, Roth, Yerkes, Parekh-Olmedo, & Kmiec, 2006). The most robust ODN inhibitor of aggregation is a single stranded oligonucleotide composed of 20 guanosine residues termed, G20. It is unique in its propensity to form a secondary structure known as a G-quadruplex. For this thesis, analysis was done on the G-quadruplex forming G20 to determine if its structure is central to its aggregation inhibition activity. Circular dichroism and Atomic Force Microscopy(AFM) experiments were carried out to investigate the secondary structure and it was determined that G20 most likely forms a “G-wire” formation of a G-quadruplex and that this structure is important for the interaction necessary for inhibition of mutant huntingtin aggregation. The interaction between G20 and huntingtin was investigated in several aggregation models of huntingtin by both in vitro and in vivo assays. The results indicate that G20 acts by directly binding to huntingtin, and that this interaction is dependent on the unique structure formed by G20 and on the process of mutant huntingtin aggregation. We hypothesize that G20 inhibits mutant huntingtin aggregation through a direct and structurally specific interaction. | en |
Advisor | Kmiec, Eric B. | |
Degree | M.S. | |
Department | University of Delaware, Department of Biological Sciences | |
URL | http://udspace.udel.edu/handle/19716/5482 | |
Publisher | University of Delaware | en |
dc.subject.lcsh | Oligonucleotides | |
dc.subject.lcsh | Glutamine | |
dc.subject.lcsh | Huntington’s chorea | |
Title | Characterization of the interaction between a stable G-quartet forming oligonucleotide and huntingtin with an expanded poly-glutamine region | en |
Type | Thesis | en |