Journal Article

DZNE-2020-07921

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Poly-glycine-alanine exacerbates C9orf72 repeat expansion-mediated DNA damage via sequestration of phosphorylated ATM and loss of nuclear hnRNPA3.

Nihei, Y. (First author)DZNE* ; Mori, K. ; Werner, G. ; Arzberger, T.DZNE* ; Zhou, Q.DZNE* ; Khosravi, B.DZNE* ; Japtok, J. ; Hermann, A.DZNE* ; Sommacal, A. ; Weber, M. ; Degeneration, G. C. f. F. L. ; Alliance, B. B. B. ; Kamp, F. ; Nuscher, B. ; Edbauer, D.DZNE* ; Haass, C. (Last author)DZNE*

2020
Springer Heidelberg

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Please use a persistent id in citations: doi:10.1007/s00401-019-02082-0

Abstract: Repeat expansion in C9orf72 causes amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Expanded sense and antisense repeat RNA transcripts in C9orf72 are translated into five dipeptide-repeat proteins (DPRs) in an AUG-independent manner. We previously identified the heterogeneous ribonucleoprotein (hnRNP) A3 as an interactor of the sense repeat RNA that reduces its translation into DPRs. Furthermore, we found that hnRNPA3 is depleted from the nucleus and partially mislocalized to cytoplasmic poly-GA inclusions in C9orf72 patients, suggesting that poly-GA sequesters hnRNPA3 within the cytoplasm. We now demonstrate that hnRNPA3 also binds to the antisense repeat RNA. Both DPR production and deposition from sense and antisense RNA repeats are increased upon hnRNPA3 reduction. All DPRs induced DNA double strand breaks (DSB), which was further enhanced upon reduction of hnRNPA3. Poly-glycine-arginine and poly-proline-arginine increased foci formed by phosphorylated Ataxia Telangiectasia Mutated (pATM), a major sensor of DSBs, whereas poly-glycine-alanine (poly-GA) evoked a reduction of pATM foci. In dentate gyri of C9orf72 patients, lower nuclear hnRNPA3 levels were associated with increased DNA damage. Moreover, enhanced poly-GA deposition correlated with reduced pATM foci. Since cytoplasmic pATM deposits partially colocalized with poly-GA deposits, these results suggest that poly-GA, the most frequent DPR observed in C9orf72 patients, differentially causes DNA damage and that poly-GA selectively sequesters pATM in the cytoplasm inhibiting its recruitment to sites of DNA damage. Thus, mislocalization of nuclear hnRNPA3 caused by poly-GA leads to increased poly-GA production, which partially depletes pATM, and consequently enhances DSB.

Keyword(s): Aged (MeSH) ; Amyotrophic Lateral Sclerosis: genetics (MeSH) ; Amyotrophic Lateral Sclerosis: metabolism (MeSH) ; Ataxia Telangiectasia Mutated Proteins: metabolism (MeSH) ; C9orf72 Protein: genetics (MeSH) ; DNA Damage: genetics (MeSH) ; Dinucleotide Repeats: physiology (MeSH) ; Female (MeSH) ; Frontotemporal Lobar Degeneration: genetics (MeSH) ; Frontotemporal Lobar Degeneration: metabolism (MeSH) ; Heterogeneous-Nuclear Ribonucleoprotein Group A-B: metabolism (MeSH) ; Humans (MeSH) ; Male (MeSH) ; Middle Aged (MeSH) ; Phosphorylation (MeSH)

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Contributing Institute(s):

1. ALS, FTLD and Zebrafish models (AG Haass old)
2. Clinical Dementia Research München (Clinical Dementia Research München)
3. Cell Biology of Neurodegeneration (AG Edbauer)
4. Clinical Dementia Research Rostock /Greifswald (AG Teipel)
5. Adaptive Immunity in Neurodegeneration (AG Zhou)

Research Program(s):

1. 342 - Disease Mechanisms and Model Systems (POF3-342) (POF3-342)
2. 344 - Clinical and Health Care Research (POF3-344) (POF3-344)

Appears in the scientific report 2020

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Database coverage:
; ; ; BIOSIS Previews ; Clarivate Analytics Master Journal List ; Current Contents - Life Sciences ; Ebsco Academic Search ; IF >= 15 ; JCR ; SCOPUS ; Web of Science Core Collection

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