High-throughput targeted sequencing to assess the role of RNA-binding proteins in ALS
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Thank you for your interest. You will find on this webpage supplementary informations for this poster.
Abstract
ALS is a devastating adult-onset neurodegenerative disease that attacks upper and lower motor neurons. Symptoms of this disease are a progressive and fatal muscle paralysis, causing death within 2 to 5 years of disease onset.
Mutations in several genes have been linked to both sporadic or familial forms of ALS, including SOD1, TARDBP, FUS/TLS and others. Two of these genes, TARDBP (TDP-43) and FUS/TLS (FUS) both encode similar types of RNA-binding proteins and have been identified as components of pathological inclusions in neurons of ALS patients. An emerging concept suggested by the discoveries of FUS and TDP-43 in ALS is that defects in RNA metabolism might contribute to the pathogenesis.
Poster PDF
You can download a PDF copy of the "A yeast functional screen predicts new ALS disease genes" poster.
Targeted exon capture and sequencing in sporadic amyotrophic lateral sclerosis.
Couthouis J, Raphael AR, Daneshjou R, Gitler AD.
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease that results in progressive degeneration of motor neurons, ultimately leading to paralysis and death. Approximately 10% of ALS cases are familial, with the remaining 90% of cases being sporadic. Genetic studies in familial cases of ALS have been extremely informative in determining the causative mutations behind ALS, especially as the same mutations identified in familial ALS can also cause sporadic disease. However, the cause of ALS in approximately 30% of familial cases and in the majority of sporadic cases remains unknown. Sporadic ALS cases represent an underutilized resource for genetic information about ALS; therefore, we undertook a targeted sequencing approach of 169 known and candidate ALS disease genes in 242 sporadic ALS cases and 129 matched controls to try to identify novel variants linked to ALS. We found a significant enrichment in novel and rare variants in cases versus controls, indicating that we are likely identifying disease associated mutations. This study highlights the utility of next generation sequencing techniques combined with functional studies and rare variant analysis tools to provide insight into the genetic etiology of a heterogeneous sporadic disease.
References
PLoS Genet. 2014 October 9, 2014 vol. 10 no. e1004704
Pubmed: PMID 25299611 DOI: 10.1371/journal.pgen.1004704
A yeast functional screen predicts new candidate ALS disease genes.
Couthouis J, Hart MP, Shorter J, DeJesus-Hernandez M, Erion R, Oristano R, Liu AX, Ramos D, Jethava N, Hosangadi D, Epstein J, Chiang A, Diaz Z, Nakaya T, Ibrahim F, Kim HJ, Solski JA, Williams KL, Mojsilovic-Petrovic J, Ingre C, Boylan K, Graff-Radford NR, Dickson DW, Clay-Falcone D, Elman L, McCluskey L, Greene R, Kalb RG, Lee VM, Trojanowski JQ, Ludolph A, Robberecht W, Andersen PM, Nicholson GA, Blair IP, King OD, Bonini NM, Van Deerlin V, Rademakers R, Mourelatos Z, Gitler AD.
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating and universally fatal neurodegenerative disease. Mutations in two related RNA-binding proteins, TDP-43 and FUS, that harbor prion-like domains, cause some forms of ALS. There are at least 213 human proteins harboring RNA recognition motifs, including FUS and TDP-43, raising the possibility that additional RNA-binding proteins might contribute to ALS pathogenesis. We performed a systematic survey of these proteins to find additional candidates similar to TDP-43 and FUS, followed by bioinformatics to predict prion-like domains in a subset of them. We sequenced one of these genes, TAF15, in patients with ALS and identified missense variants, which were absent in a large number of healthy controls. These disease-associated variants of TAF15 caused formation of cytoplasmic foci when expressed in primary cultures of spinal cord neurons. Very similar to TDP-43 and FUS, TAF15 aggregated in vitro and conferred neurodegeneration in Drosophila, with the ALS-linked variants having a more severe effect than wild type. Immunohistochemistry of postmortem spinal cord tissue revealed mislocalization of TAF15 in motor neurons of patients with ALS. We propose that aggregation-prone RNA-binding proteins might contribute very broadly to ALS pathogenesis and the genes identified in our yeast functional screen, coupled with prion-like domain prediction analysis, now provide a powerful resource to facilitate ALS disease gene discovery.
References
PNAS December 27, 2011 vol. 108 no. 52 20881-20890
Pubmed: PMID 22065782 DOI: 10.1073/pnas.1109434108
Evaluating the role of the FUS/TLS-related gene EWSR1 in amyotrophic lateral sclerosis.
Couthouis J, Hart MP, Erion R, King OD, Diaz Z, Nakaya T, Ibrahim F, Kim HJ, Mojsilovic-Petrovic J, Panossian S, Kim CE, Frackelton EC, Solski JA, Williams KL, Clay-Falcone D, Elman L, McCluskey L, Greene R, Hakonarson H, Kalb RG, Lee VM, Trojanowski JQ, Nicholson GA, Blair IP, Bonini NM, Van Deerlin VM, Mourelatos Z, Shorter J, Gitler AD.
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting motor neurons. Mutations in related RNA-binding proteins TDP-43, FUS/TLS and TAF15 have been connected to ALS. These three proteins share several features, including the presence of a bioinformatics-predicted prion domain, aggregation-prone nature in vitro and in vivo and toxic effects when expressed in multiple model systems. Given these commonalities, we hypothesized that a related protein, EWSR1 (Ewing sarcoma breakpoint region 1), might also exhibit similar properties and therefore could contribute to disease. Here, we report an analysis of EWSR1 in multiple functional assays, including mutational screening in ALS patients and controls. We identified three missense variants in EWSR1 in ALS patients, which were absent in a large number of healthy control individuals. We show that disease-specific variants affect EWSR1 localization in motor neurons. We also provide multiple independent lines of in vitro and in vivo evidence that EWSR1 has similar properties as TDP-43, FUS and TAF15, including aggregation-prone behavior in vitro and ability to confer neurodegeneration in Drosophila. Postmortem analysis of sporadic ALS cases also revealed cytoplasmic mislocalization of EWSR1. Together, our studies highlight a potential role for EWSR1 in ALS, provide a collection of functional assays to be used to assess roles of additional RNA-binding proteins in disease and support an emerging concept that a class of aggregation-prone RNA-binding proteins might contribute broadly to ALS and related neurodegenerative diseases.
References
Hum. Mol. Genet. (2012) 21 (13): 2899-2911
Pubmed: PMID 22454397 DOI: 10.1093/hmg/dds116
Exome sequencing to identify de novo mutations in sporadic ALS trios.
Chesi A, Staahl BT, Jovičić A, Couthouis J, Fasolino M, Raphael AR, Yamazaki T, Elias L, Polak M, Kelly C, Williams KL, Fifita JA, Maragakis NJ, Nicholson GA, King OD, Reed R, Crabtree GR, Blair IP, Glass JD, Gitler AD.
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease whose causes are still poorly understood. To identify additional genetic risk factors, we assessed the role of de novo mutations in ALS by sequencing the exomes of 47 ALS patients and both of their unaffected parents (n = 141 exomes). We found that amino acid-altering de novo mutations were enriched in genes encoding chromatin regulators, including the neuronal chromatin remodeling complex (nBAF) component SS18L1 (also known as CREST). CREST mutations inhibited activity-dependent neurite outgrowth in primary neurons, and CREST associated with the ALS protein FUS. These findings expand our understanding of the ALS genetic landscape and provide a resource for future studies into the pathogenic mechanisms contributing to sporadic ALS.
References
Nat Neurosci. 2013 Jul;16(7):851-5
Pubmed: PMID 23708140 DOI: 10.1038/nn.3412
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Last modified Thuesday, 09-Sep-2014 18:15:48 PDT