Investigating mechanisms of repeat-associated non-aug translation in neurodegenerative disease
Abstract/Contents
- Abstract
- A novel form of translation has been discovered in several neurodegenerative and muscular diseases which contain causative microsatellite expansions. This Repeat-Associated Non-ATG translation (RAN translation) occurs in the absence of a canonical AUG codon at disease-causing expansions. Expansion-harboring transcripts form com-plex secondary structures such as hairpins or G-quadruplexes. The protein products of RAN translation are toxic in cell culture and disease models ranging from yeast to mice and are found to accumulate in disease-relevant patient tissues. The basic mechanisms of RAN translation initiation have not been thoroughly investigated. The inhibition of RAN translation to prevent toxic protein production has been proposed as one therapeutic option for this class of diseases. Thus, a comprehensive characterization of machinery involved in and molecular mechanisms underlying RAN translation are of utmost importance in designing therapeutic strategies. Understanding how these mechanisms differ from AUG-initiated translation will broaden our understanding of non-canonically initiated translation. In Chapter 2, I perform a genetic screen in yeast in order to identify novel trans regulators of RAN translation. I found that RPS25 specifically regulates the efficient RAN translation of GGGGCC repeat expansions in the C9orf72 gene. Moreover, I found that RPS25 can also regulate the RAN translation of ATXN2 and HTT CAG expansions. Importantly, the reduction of RPS25 in patient-derived cell lines reduced the amount of DPRs detected and extended survival in a c9ALS Drosophila model. The result in Drosophila provides further evidence to support the model that DPRs are the predominant toxic species driving neurodegeneration. I provide data for one of the first protein factors identified to be involved in RAN translation and future work will delve into the precise mechanisms by which RPS25 coordinates an increase in efficiency of RAN translation. Ribosomal protein deficiencies are known to cause a whole host of consequences including ribosomal biogenesis defects and subsequent nucleolar stress. The effect of the deletion of RPS25 in cells is investigated in Chapter 3. I find that in our system, RPS25 is likely not functioning through a p53 axis to account for the effects seen in Chapter 2. Furthermore, I generate two mouse models: one strain harbors a deletion of exon 2 in the mouse RPS25 gene and the second strain is an RPS25 exon 2 floxed strain. I dis-cuss phenotypes observed in a small cohort of the RPS25 knockout strain mice and end with a discussion of future studies that will utilize these two strains
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2020; ©2020 |
| Publication date | 2020; 2020 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Yamada, Shizuka Bridget |
|---|---|
| Degree supervisor | Gitler, Aaron D |
| Thesis advisor | Gitler, Aaron D |
| Thesis advisor | Brandman, Onn |
| Thesis advisor | Frydman, Judith |
| Thesis advisor | Puglisi, Joseph D |
| Thesis advisor | Stearns, Tim |
| Degree committee member | Brandman, Onn |
| Degree committee member | Frydman, Judith |
| Degree committee member | Puglisi, Joseph D |
| Degree committee member | Stearns, Tim |
| Associated with | Stanford University, Department of Biology |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Shizuka Bridget Yamada |
|---|---|
| Note | Submitted to the Department of Biology |
| Thesis | Thesis Ph.D. Stanford University 2020 |
| Location | electronic resource |
Access conditions
- Copyright
- © 2020 by Shizuka Bridget Yamada
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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