Article

Expression of human FUS protein in Drosophila leads to progressive neurodegeneration

National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Science and Peking Union Medical College, Tsinghua University, Beijing, China.
Protein & Cell (Impact Factor: 2.85). 06/2011; 2(6):477-86. DOI: 10.1007/s13238-011-1065-7
Source: PubMed

ABSTRACT Mutations in the Fused in sarcoma/Translated in liposarcoma gene (FUS/TLS, FUS) have been identified among patients with amyotrophic lateral sclerosis (ALS). FUS protein aggregation is a major pathological hallmark of FUS proteinopathy, a group of neurodegenerative diseases characterized by FUS-immunoreactive inclusion bodies. We prepared transgenic Drosophila expressing either the wild type (Wt) or ALS-mutant human FUS protein (hFUS) using the UAS-Gal4 system. When expressing Wt, R524S or P525L mutant FUS in photoreceptors, mushroom bodies (MBs) or motor neurons (MNs), transgenic flies show age-dependent progressive neural damages, including axonal loss in MB neurons, morphological changes and functional impairment in MNs. The transgenic flies expressing the hFUS gene recapitulate key features of FUS proteinopathy, representing the first stable animal model for this group of devastating diseases.

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Available from: Li Zhu, Oct 17, 2014
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    • "Cytosolic mislocalization and deposition of the FET proteins may also create a toxic 'gain-of-function', e.g. through aberrant binding of cytosolic RNA targets (Hoell et al., 2011) or altered protein–protein interactions. Overexpression of FUS or mutant FUS in yeast and various model animals indeed causes toxicity and recapitulates certain disease features (Chen et al., 2011; Fushimi et al., 2011; Huang et al., 2011; Ju et al., 2011; Kabashi et al., 2011; Kryndushkin et al., 2011; Lanson et al., 2011; Murakami et al., 2012; Sun et al., 2011; Vaccaro et al., 2012; Verbeeck et al., 2012). However under physiological conditions, FUS levels appear to be tightly regulated by an autoregulatory mechanism (Lagier-Tourenne et al., 2012), suggesting that overexpression models should be interpreted with caution. "
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    ABSTRACT: Fused in sarcoma (FUS) is a nuclear DNA/RNA binding protein that regulates different steps of gene expression, including transcription, splicing and mRNA transport. FUS has been implicated in neurodegeneration, since mutations in FUS cause familial amyotrophic lateral sclerosis (ALS-FUS) and lead to the cytosolic deposition of FUS in the brain and spinal cord of ALS-FUS patients. Moreover, FUS and two related proteins of the same protein family (FET family) are co-deposited in cytoplasmic inclusions in a subset of patients with frontotemporal lobar degeneration (FTLD-FUS). Cytosolic deposition of these otherwise nuclear proteins most likely causes the loss of a yet unknown essential nuclear function and/or the gain of a toxic function in the cytosol. Here we summarize what is known about the physiological functions of the FET proteins in the nucleus and cytoplasm and review the distinctive pathomechanisms that lead to the deposition of only FUS in ALS-FUS, but all three FET proteins in FTLD-FUS. We suggest that ALS-FUS is caused by a selective dysfunction of FUS, while FTLD-FUS may be caused by a dysfunction of the entire FET family.
    Molecular and Cellular Neuroscience 04/2013; 56. DOI:10.1016/j.mcn.2013.03.006 · 3.73 Impact Factor
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    • "In particular, the FUS-ΔNLS mutation lacks the NLS and causes a relatively aggressive ALS clinical phenotype with an early onset [14]. It has been proposed that the loss of a nuclear function or the gain of a cytosolic function or both can be the possible cause for the disease [15] [16] [17]. "
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    ABSTRACT: Mutations in the RNA binding protein FUS (fused in sarcoma) have been linked to a subset of familial amyotrophic lateral sclerosis (ALS) cases. The mutations are clustered in the C-terminal nuclear localization sequence (NLS). Various FUS mutants accumulate in cytoplasm whereas wild-type (WT) FUS is mainly nuclear. Here we investigate the effect of one ALS causing mutant (FUS-ΔNLS, also known as R495X) on gene splicing and expression using genome wide exon-junction arrays. Using a non-neuronal stable cell line with inducible FUS expression, we detected early changes in RNA composition. In particular, mutant FUS-ΔNLS increased calcium/calmodulin-dependent protein kinase II inhibitor 2 (CAMK2N2) at both mRNA and protein levels, whereas WT-FUS had no effect. Chromatin immunoprecipitation experiments showed that FUS-ΔNLS accumulated at the CAMK2N2 promoter region, whereas promoter occupation by WT-FUS remained constant. Given the loss of FUS-ΔNLS in the nucleus through the mutation-induced translocation, this increase of promoter occupancy is surprising. It indicates that, despite the obvious cytoplasmic accumulation, FUS-ΔNLS can act through a nuclear gain of function mechanism.
    Biochimica et Biophysica Acta 03/2013; 1832(8). DOI:10.1016/j.bbadis.2013.03.015 · 4.66 Impact Factor
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    • "Two previous reports described that expression of the wild-type form of human FUS in the Drosophila eye leads to a mild retinal phenotype (Chen et al., 2011; Lanson et al., 2011). Consistent with these studies, we found that FUS proteins are mainly recovered as soluble forms and that their overexpression results in a mild eye phenotype, with malformed interommatidial bristles and the appearance of ectopic extensions, a phenotype reminiscent of that associated with the overexpression of the Ovo/Shavenbaby transcription factor (Delon et al., 2003). "
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    ABSTRACT: Recently, the fused in sarcoma/translated in liposarcoma (FUS) protein has been identified as a major constituent of nuclear and/or cytoplasmic ubiquitin-positive inclusions in patients with frontotemporal lobar degeneration or amyotrophic lateral sclerosis. The molecular mechanisms underlying FUS toxicity are currently not understood. To address aspects of FUS pathogenesis in vivo, we have generated new Drosophila transgenic models expressing a full-length wild-type isoform of human FUS protein. We found that when expressed in retinal cells, FUS proteins are mainly recovered as soluble forms, and their overexpression results in a mild eye phenotype, with malformed interommatidial bristles and the appearance of ectopic extensions. On the other hand, when FUS proteins are specifically targeted to adult differentiated neurons, they are mainly recovered as insoluble forms, and their overexpression drastically reduces fly life span. Importantly, FUS neurotoxicity occurs regardless of inclusion formation. Lastly, we showed that molecular chaperones reduce FUS toxicity by modulating protein solubility. Altogether, our data indicate that accumulation of insoluble non-aggregated FUS forms might represent the primary toxic species in human FUS proteinopathies.
    Neurobiology of aging 11/2011; 33(5):1008.e1-15. DOI:10.1016/j.neurobiolaging.2011.10.008 · 4.85 Impact Factor
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