Mitochondria-Dependent Cellular Toxicity of α-synuclein Modeled in Yeast

Mitochondria-Dependent Cellular Toxicity of α-synuclein Modeled in Yeast

Bibliographic Details
Main Author: Santhanakrishnan, Rajalakshmi
Language:English
Published: Wright State University / OhioLINK 2019
Subjects:
Biology
Cellular Biology
Molecular Biology
Parkinson disease
neurodegenerative disease
cellular toxicity
mitochondrial dysfunction
mitochondrial fragmentation
non-galactose condition
overexpression system
Online Access:http://rave.ohiolink.edu/etdc/view?acc_num=wright1578304595468304
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spelling ndltd-OhioLink-oai-etd.ohiolink.edu-wright15783045954683042021-08-03T07:13:46Z Mitochondria-Dependent Cellular Toxicity of α-synuclein Modeled in Yeast Santhanakrishnan, Rajalakshmi Biology Cellular Biology Molecular Biology Parkinson disease neurodegenerative disease cellular toxicity mitochondrial dysfunction mitochondrial fragmentation non-galactose condition overexpression system Parkinson’s disease is the second most common neurodegenerative disease. This disease is caused by the degeneration of dopaminergic neurons, leading to debilitating motor symptoms and early mortality. The protein α-synuclein (α-syn), encoded by SNCA, misfolds and forms inclusions in Parkinson’s disease brains. When α-syn is overexpressed in yeast, it causes cellular toxicity and an increased number of aggregates, recapitulating the toxic phenotypes observed in humans and animal models. Yeast models are a powerful tool to perform high-throughput overexpression screening to identify modifiers of α-syn toxicity. α-syn causes mitochondrial dysfunction by inhibiting complex I and inducing mitochondrial fragmentation. Prior screening of α-syn were limited to only the galactose condition, where mitochondrial function is dispensable. Previous screening was performed exclusively with the GAL1 promoter, restricting the genes to only those induced by galactose. We have validated an overexpression system using GAL3 alleles that can induce genes under mitochondrial-dependent glycerol-ethanol condition and other non-galactose conditions (calorie restriction, nitrogen starvation and raffinose). α-syn showed discrepancy in the correlation of toxicity and aggregation in non-galactose conditions. Compared to galactose, under glycerol-ethanol condition, α-syn exhibited higher toxicity, formed more aggregates, and decreased viability and respiratory competency despite having similar expression under the two conditions. We screened 14,827 human gene clones and identified 87 that can suppress α-syn toxicity in glycerol-ethanol. Genes involved in RNA polymerase II function, anterior-posterior axis and nucleoplasm were overrepresented. Among the suppressor hits, we identified four 14-3-3 protein isotypes (β, γ, θ, and ζ). None of the four suppressors suppressed the toxicity under galactose. However, the 14-3-3 suppressors did not reduce aggregates under glycerol-ethanol. No increase in respiratory competency was observed; however, 14-3-3β was seen to effectively reduce the number of cells that accumulate ROS. Overall, we have created an overexpression system that describes a new path for performing screening in non-galactose conditions. Our results based on novel phenotypes of α-syn show that screening in these conditions is indeed important. We have identified previously unknown suppressors of α-syn toxicity and ruled out underlying mechanisms of action. 2019 English text Wright State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=wright1578304595468304 http://rave.ohiolink.edu/etdc/view?acc_num=wright1578304595468304 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection NDLTD
language English
sources NDLTD
topic Biology
Cellular Biology
Molecular Biology
Parkinson disease
neurodegenerative disease
cellular toxicity
mitochondrial dysfunction
mitochondrial fragmentation
non-galactose condition
overexpression system
spellingShingle Biology
Cellular Biology
Molecular Biology
Parkinson disease
neurodegenerative disease
cellular toxicity
mitochondrial dysfunction
mitochondrial fragmentation
non-galactose condition
overexpression system
Santhanakrishnan, Rajalakshmi
Mitochondria-Dependent Cellular Toxicity of α-synuclein Modeled in Yeast
author Santhanakrishnan, Rajalakshmi
author_facet Santhanakrishnan, Rajalakshmi
author_sort Santhanakrishnan, Rajalakshmi
title Mitochondria-Dependent Cellular Toxicity of α-synuclein Modeled in Yeast
title_short Mitochondria-Dependent Cellular Toxicity of α-synuclein Modeled in Yeast
title_full Mitochondria-Dependent Cellular Toxicity of α-synuclein Modeled in Yeast
title_fullStr Mitochondria-Dependent Cellular Toxicity of α-synuclein Modeled in Yeast
title_full_unstemmed Mitochondria-Dependent Cellular Toxicity of α-synuclein Modeled in Yeast
title_sort mitochondria-dependent cellular toxicity of α-synuclein modeled in yeast
publisher Wright State University / OhioLINK
publishDate 2019
url http://rave.ohiolink.edu/etdc/view?acc_num=wright1578304595468304
work_keys_str_mv AT santhanakrishnanrajalakshmi mitochondriadependentcellulartoxicityofasynucleinmodeledinyeast
_version_ 1719456836727341056

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