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Kim SA, D'Acunto VF, Kokona B, Hofmann J, Cunningham NR, Bistline EM, Garcia FJ, Akhtar NM, Hoffman SH, Doshi SH, Ulrich KM, Jones NM, Bonini NM, Roberts CM, Link CD, Laue TM, Fairman R. Sedimentation Velocity Analysis with Fluorescence Detection of Mutant Huntingtin Exon 1 Aggregation in Drosophila melanogaster and Caenorhabditis elegans. Biochemistry 2017; 56:4676-4688. [PMID: 28786671 DOI: 10.1021/acs.biochem.7b00518] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
At least nine neurodegenerative diseases that are caused by the aggregation induced by long tracts of glutamine sequences have been identified. One such polyglutamine-containing protein is huntingtin, which is the primary factor responsible for Huntington's disease. Sedimentation velocity with fluorescence detection is applied to perform a comparative study of the aggregation of the huntingtin exon 1 protein fragment upon transgenic expression in Drosophila melanogaster and Caenorhabditis elegans. This approach allows the detection of aggregation in complex mixtures under physiologically relevant conditions. Complementary methods used to support this biophysical approach included fluorescence microscopy and semidenaturing detergent agarose gel electrophoresis, as a point of comparison with earlier studies. New analysis tools developed for the analytical ultracentrifuge have made it possible to readily identify a wide range of aggregating species, including the monomer, a set of intermediate aggregates, and insoluble inclusion bodies. Differences in aggregation in the two animal model systems are noted, possibly because of differences in levels of expression of glutamine-rich sequences. An increased level of aggregation is shown to correlate with increased toxicity for both animal models. Co-expression of the human Hsp70 in D. melanogaster showed some mitigation of aggregation and toxicity, correlating best with inclusion body formation. The comparative study emphasizes the value of the analytical ultracentrifuge equipped with fluorescence detection as a useful and rigorous tool for in situ aggregation analysis to assess commonalities in aggregation across animal model systems.
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Affiliation(s)
- Surin A Kim
- Department of Biology, Haverford College , Haverford, Pennsylvania 19041, United States
| | - Victoria F D'Acunto
- Department of Biology, Haverford College , Haverford, Pennsylvania 19041, United States
| | - Bashkim Kokona
- Department of Biology, Haverford College , Haverford, Pennsylvania 19041, United States
| | - Jennifer Hofmann
- Department of Biology, Haverford College , Haverford, Pennsylvania 19041, United States
| | - Nicole R Cunningham
- Department of Biology, Haverford College , Haverford, Pennsylvania 19041, United States
| | - Emily M Bistline
- Department of Biology, Haverford College , Haverford, Pennsylvania 19041, United States
| | - F Jay Garcia
- Department of Biology, Haverford College , Haverford, Pennsylvania 19041, United States
| | - Nabeel M Akhtar
- Department of Biology, Haverford College , Haverford, Pennsylvania 19041, United States
| | - Susanna H Hoffman
- Department of Biology, Haverford College , Haverford, Pennsylvania 19041, United States
| | - Seema H Doshi
- Department of Biology, Haverford College , Haverford, Pennsylvania 19041, United States
| | - Kathleen M Ulrich
- Department of Biology, Haverford College , Haverford, Pennsylvania 19041, United States
| | - Nicholas M Jones
- Department of Psychology, Haverford College , Haverford, Pennsylvania 19041, United States
| | - Nancy M Bonini
- Department of Biology, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
| | - Christine M Roberts
- Integrative Physiology, University of Colorado Boulder , Boulder, Colorado 80309, United States
| | - Christopher D Link
- Integrative Physiology, University of Colorado Boulder , Boulder, Colorado 80309, United States
| | - Thomas M Laue
- Department of Molecular, Cellular & Biomedical Sciences, University of New Hampshire , Durham, New Hampshire 03824, United States
| | - Robert Fairman
- Department of Biology, Haverford College , Haverford, Pennsylvania 19041, United States
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Kokona B, May CA, Cunningham NR, Richmond L, Jay Garcia F, Durante JC, Ulrich KM, Roberts CM, Link CD, Stafford WF, Laue TM, Fairman R. Studying polyglutamine aggregation in Caenorhabditis elegans using an analytical ultracentrifuge equipped with fluorescence detection. Protein Sci 2015; 25:605-17. [PMID: 26647351 DOI: 10.1002/pro.2854] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 12/01/2015] [Indexed: 11/11/2022]
Abstract
This work explores the heterogeneity of aggregation of polyglutamine fusion constructs in crude extracts of transgenic Caenorhabditis elegans animals. The work takes advantage of the recent technical advances in fluorescence detection for the analytical ultracentrifuge. Further, new sedimentation velocity methods, such as the multi-speed method for data capture and wide distribution analysis for data analysis, are applied to improve the resolution of the measures of heterogeneity over a wide range of sizes. The focus here is to test the ability to measure sedimentation of polyglutamine aggregates in complex mixtures as a prelude to future studies that will explore the effects of genetic manipulation and environment on aggregation and toxicity. Using sedimentation velocity methods, we can detect a wide range of aggregates, ranging from robust analysis of the monomer species through an intermediate and quite heterogeneous population of oligomeric species, and all the way up to detecting species that likely represent intact inclusion bodies based on comparison to an analysis of fluorescent puncta in living worms by confocal microscopy. Our results support the hypothesis that misfolding of expanded polyglutamine tracts into insoluble aggregates involves transitions through a number of stable intermediate structures, a model that accounts for how an aggregation pathway can lead to intermediates that can have varying toxic or protective attributes. An understanding of the details of intermediate and large-scale aggregation for polyglutamine sequences, as found in neurodegenerative diseases such as Huntington's Disease, will help to more precisely identify which aggregated species may be involved in toxicity and disease.
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Affiliation(s)
- Bashkim Kokona
- Department of Biology, Haverford College, Haverford, Pennsylvania, 19041
| | - Carrie A May
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, 03824
| | | | - Lynn Richmond
- Department of Biology, Haverford College, Haverford, Pennsylvania, 19041
| | - F Jay Garcia
- Department of Biology, Haverford College, Haverford, Pennsylvania, 19041
| | - Julia C Durante
- Department of Biology, Haverford College, Haverford, Pennsylvania, 19041
| | - Kathleen M Ulrich
- Department of Biology, Haverford College, Haverford, Pennsylvania, 19041
| | - Christine M Roberts
- Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, 80309
| | - Christopher D Link
- Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, 80309
| | - Walter F Stafford
- Boston Biomedical Research Institute, Watertown, Massachusetts, 02472
| | - Thomas M Laue
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, New Hampshire, 03824
| | - Robert Fairman
- Department of Biology, Haverford College, Haverford, Pennsylvania, 19041
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