Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.747548
Title: Molecular mechanisms of pathogenesis in Drosophila models of C9orf72 mutation associated ALS/FTD
Author: Moens, Thomas Grover
ISNI:       0000 0004 7231 3727
Awarding Body: UCL (University College London)
Current Institution: University College London (University of London)
Date of Award: 2018
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Abstract:
A GGGGCC hexanucleotide repeat expansion within the C9orf72 gene is the most common genetic cause of both amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). Toxicity has been proposed to be due to loss of function of the gene, or by a toxic gain of function, mediated either by the transcription of repetitive sense and antisense RNA molecules, or by translation of RNA into five repetitive dipeptide proteins (DPRs) via repeat associated non-ATG initiated translation. In order to fully assess the role of sense and antisense RNA in vivo, Drosophila models were created where expression of sense or antisense RNA was induced whilst suppressing the formation of DPRs. Despite the formation of cardinal pathological features (RNA binding protein sequestering intranuclear RNA foci) toxicity was not observed in these models suggesting that repeat RNA plays a limited role in disease pathogenesis. When individual DPRs are expressed in Drosophila neurons a strong toxicity is induced by the arginine containing DPRs (poly-GR and poly-PR). To gain insight into the mechanism(s) by which this toxicity occurs, the protein-interactome of these DPRs was investigated in vivo using novel transgenic Drosophila that inducibly express affinity tagged DPR constructs, with identification of interacting proteins using mass spectrometry. In parallel, inclusions of dipeptide proteins were laser-capture microdissected from patient brain tissue and enriched proteins identified by mass spectrometry. The overlap of these datasets suggested that translation may be impaired by the arginine-containing DPRs and methods were adapted to assess the rate of translation in adult Drosophila brains. In parallel, enzymelinked immunosorbent assays (ELISAs) were developed against poly-GR and an abundant non-toxic DPR poly-GP. Measurement of these proteins was performed in various model systems (transfected immortalised cell lines, induced pluripotent stem cell derived neurons, Drosophila models) to confirm the validity of the assays and the potential therapeutic value of interventions.
Supervisor: Isaacs, A. ; Partridge, L. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.747548  DOI: Not available
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