Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0003635 (apraxia)
 2,817 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A severe recessive cerebellar ataxia, Ataxia-Oculomotor Apraxia 2 (AOA2) and a juvenile onset form of dominant amyotrophic lateral sclerosis (ALS4) result from mutations of the Senataxin (SETX) gene. To begin characterization this disease protein, we developed a specific antibody to the DNA/RNA helicase domain of SETX. In murine brain, SETX concentrates in several regions, including cerebellum, hippocampus and olfactory bulb with a general neuronal expression profile, colocalizing with NeuN. In cultured cells, we found that SETX was cytoplasmically diffuse, but in the nucleus, SETX was punctate, colocalizing with fibrillarin, a marker of the nucleolus. In differentiated non-cycling cells, nuclear SETX was not restricted to the nucleolus but was diffuse within the nucleoplasm, suggesting cell-cycle-dependent localization. SETX missense mutations cluster within the N-terminus and helicase domains. Flag tagging at the N-terminus caused protein mislocation to the nucleoplasm and failure to export to the cytoplasm, suggesting that the N-terminus may be essential for correct SETX localization. We report here the first characterization of SETX protein, which may provide future insights into a new mechanism leading to neuron death.
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PMID:Senataxin, the yeast Sen1p orthologue: characterization of a unique protein in which recessive mutations cause ataxia and dominant mutations cause motor neuron disease. 1664 29

Mutations in the Senataxin gene (SETX) are associated with autosomal recessive ataxia-ocular apraxia 2 (AOA2) and autosomal dominant juvenile ALS (ALS4). Here, the authors describe novel homozygous missense mutations in SETX, M274I, and R1294C, found in two siblings with ataxia, peripheral neuropathy, and increased serum alpha-fetoprotein level and three other siblings with heterozygous missense mutations who were neurologically asymptomatic. The results demonstrate that the double missense mutations are responsible for AOA2 but not for ALS4.
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PMID:Autosomal recessive ataxia with peripheral neuropathy and elevated AFP: novel mutations in SETX. 1671 25

Ataxia with ocular apraxia type 2 (AOA2) is an autosomal recessive, early onset ataxia caused by mutations in the senataxin (SETX) gene. Ocular apraxia and increased levels of alpha-fetoprotein are characteristic but not obligate markers of the disease. AOA2 is allelic with ALS4, a motor neuron disorder of early onset and autosomal dominant inheritance. We observed a two generation family with ataxia which started at age 14 and 17 in two sibs and at age 23 in their paternal uncle.Oculomotor disturbances included strabismus, saccadic pursuit and gaze evoked nystagmus. MRI revealed severe cerebellar atrophy. All patients presented pronounced peripheral neuropathy with wasting of hand and leg muscles resembling distal motor neuronopathy. Increased alphafetoprotein levels triggered genetic analyses of SETX. We found the sib pair to be compound heterozygous for a single base deletion c.2835delC, resulting in a frameshift mutation and causing nonsense related mRNA decay, and a base exchange c.6106G > A, resulting in abnormal splicing and skipping of exon 15. The similarly affected uncle was homozygous for the c.6106G > A mutation probably due to distant consanguinity in the paternal branch of the family. Pseudodominant occurrence in two generations has not been described before in AOA2 and led, in this family, to false categorization as dominant ataxia before SETX mutations were detected. Clinically this family presented with a phenotype combining typical features of AOA2 and ALS4; thus extending the phenotypic spectrum of SETX mutations.
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PMID:"Pseudodominant inheritance" of ataxia with ocular apraxia type 2 (AOA2). 1835 Mar 59

Senataxin (SETX) is an RNA/DNA helicase implicated in transcription termination and the DNA damage response and is mutated in two distinct neurological disorders: AOA2 (ataxia oculomotor apraxia 2) and ALS4 (amyotrophic lateral sclerosis 4). Here we provide evidence that Rrp45, a subunit of the exosome, associates with SETX in a manner dependent on SETX sumoylation. We show that the interaction and SETX sumoylation are disrupted by SETX mutations associated with AOA2 but not ALS4. Furthermore, Rrp45 colocalizes with SETX in distinct foci upon induction of transcription-related DNA damage. Our results thus provide evidence for a SUMO-dependent interaction between SETX and the exosome, disrupted in AOA2, that targets the exosome to sites of DNA damage.
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PMID:A SUMO-dependent interaction between Senataxin and the exosome, disrupted in the neurodegenerative disease AOA2, targets the exosome to sites of transcription-induced DNA damage. 2410 44

Development of Alzheimer's disease (AD) is characterized by progressive neuronal death and a decline in learning and memory. Mutations in human senataxin (SETX), an ortholog yeast protein of Sen1, have been identified to cause the syndrome of ataxia with oculomotor apraxia type 2 (AOA2) and juvenile amyotrophic lateral sclerosis (ALS4), two types of progressive motor neuron degeneration. However, the relationship between the SETX gene, which is involved in the regulation of RNA processing and DNA repair, and the predisposition for AD remains unclear. In this research, potential association of polymorphisms in the SETX gene with AD was investigated. A case-control study of a Chinese Han population in Taiwan was performed. Three single-nucleotide polymorphisms (SNPs), 3455T>G (rs3739922), 3576T>G (rs1185193) and 7759A>G (rs1056899) were studied. The experimental data showed that upon genotyping of the exonic polymorphism in the SETX gene, the T allele appeared at a lower rate than the G allele at position 3455 in AD patients compared with normal groups (P < 0.05, odds ratio (OR), 0.59, 95% confidence interval (CI), 0.40-0.89). Subjects with the GA genotype at position 7759 have higher incidences of AD development than with the AA genotype (P < 0.05, OR, 6.45, 95% CI, 1.24 to 33.70). Our results also showed that with six haplotypes (Hts) observed from the analyzed polymorphisms, distributions of the Ht4-GAA and Ht5-GCA haplotypes appeared to be significant 'risk' haplotypes between AD patients and controls (both P < 0.05, OR, 8.44, 95% CI, 1.07-66.60). These observations suggest that genetic variations in the SETX gene may contribute to AD pathogenesis in the Taiwanese Han population.
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PMID:Association of genetic variants in senataxin and Alzheimer's disease in a Chinese Han population in Taiwan. 2469 97

Senataxin, encoded by the SETX gene, contributes to multiple aspects of gene expression, including transcription and RNA processing. Mutations in SETX cause the recessive disorder ataxia with oculomotor apraxia type 2 (AOA2) and a dominant juvenile form of amyotrophic lateral sclerosis (ALS4). To assess the functional role of senataxin in disease, we examined differential gene expression in AOA2 patient fibroblasts, identifying a core set of genes showing altered expression by microarray and RNA-sequencing. To determine whether AOA2 and ALS4 mutations differentially affect gene expression, we overexpressed disease-specific SETX mutations in senataxin-haploinsufficient fibroblasts and observed changes in distinct sets of genes. This implicates mutation-specific alterations of senataxin function in disease pathogenesis and provides a novel example of allelic neurogenetic disorders with differing gene expression profiles. Weighted gene co-expression network analysis (WGCNA) demonstrated these senataxin-associated genes to be involved in both mutation-specific and shared functional gene networks. To assess this in vivo, we performed gene expression analysis on peripheral blood from members of 12 different AOA2 families and identified an AOA2-specific transcriptional signature. WGCNA identified two gene modules highly enriched for this transcriptional signature in the peripheral blood of all AOA2 patients studied. These modules were disease-specific and preserved in patient fibroblasts and in the cerebellum of Setx knockout mice demonstrating conservation across species and cell types, including neurons. These results identify novel genes and cellular pathways related to senataxin function in normal and disease states, and implicate alterations in gene expression as underlying the phenotypic differences between AOA2 and ALS4.
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PMID:Mutation of senataxin alters disease-specific transcriptional networks in patients with ataxia with oculomotor apraxia type 2. 2476 Jul 70

Interest in senataxin biology began in 2004 when mutations were first identified in what was then a novel protein. Dominantly inherited mutations were documented in rare juvenile-onset, motor neuron disease pedigrees in a familial form of amyotrophic lateral sclerosis (ALS4), while recessive mutations were found to cause a severe early-onset ataxia with oculomotor apraxia (AOA2) that is actually the second most common recessive ataxia after Freidreich's ataxia. From earlier studies of sen1p, the yeast ortholog of senataxin, a range of important RNA processing functions have been attributed to this protein. Like sen1p, senataxin contains a helicase domain to interact with RNA and an amino-terminal domain for critical protein interactions. Senataxin also joins a group of important proteins responsible for maintaining RNA transcriptome homeostasis, including FUS, TDP-43, and SMN that can all cause familial forms of motor neuron disease (MND). Independent of this association, senataxin is gaining attention for its role in maintaining genomic stability. Senataxin has been shown to resolve R-Loop structures, which form when nascent RNA hybridizes to DNA, displacing the non-transcribed strand. But in cycling cells, senataxin is also found at nuclear foci during the S/G2 cell-cycle phase, and may function at sites of specific collision between components of the replisome and transcription machinery. Which of these important processes is most critical to prevent neurodegeneration remains unknown, but our evolving understanding of these processes will be crucial not only for understanding senataxin's role in neurological disease, but also in a number of fundamentally important cellular functions.
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PMID:Unwinding the role of senataxin in neurodegeneration. 2572 27

The human helicase senataxin (SETX) has been linked to the neurodegenerative diseases amyotrophic lateral sclerosis (ALS4) and ataxia with oculomotor apraxia (AOA2). Here we identified a role for SETX in controlling the antiviral response. Cells that had undergone depletion of SETX and SETX-deficient cells derived from patients with AOA2 had higher expression of antiviral mediators in response to infection than did wild-type cells. Mechanistically, we propose a model whereby SETX attenuates the activity of RNA polymerase II (RNAPII) at genes stimulated after a virus is sensed and thus controls the magnitude of the host response to pathogens and the biogenesis of various RNA viruses (e.g., influenza A virus and West Nile virus). Our data indicate a potentially causal link among inborn errors in SETX, susceptibility to infection and the development of neurologic disorders.
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PMID:Senataxin suppresses the antiviral transcriptional response and controls viral biogenesis. 2582 50

Mutations in Senataxin (SETX) gene causes two types of neurological disorders, Amyotrophic Lateral Sclerosis (ALS4) and Ataxia with Oculomotor Apraxia type 2 (AOA2). Recent studies in cultured cells suggest that SETX plays a crucial role at the interface of transcription and the DNA damage response. Whether SETX can alter translational of specific RNA is not known. In this study, we report that expressing AOA2-causative truncated form of human SETX in Drosophila neurons alters the development of neuromuscular junction (NMJ) synapses. Interestingly, we found that expressing this truncated form of SETX in Drosophila muscles resulted in an alteration of translational repression of an RNA-binding protein, Embryonic Lethal Abnormal Vision (Elav). Elav is transcribed in all tissues but remains translationally repressed except in neurons. Thus, our data suggest that an altered repression profile of RNA by SETX mutants could be one of the mechanisms underlying ALS4 or AOA2 pathogenesis.
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PMID:Altered translational repression of an RNA-binding protein, Elav by AOA2-causative Senataxin mutation. 2824 18

Ataxia with oculomotor apraxia 2 (AOA-2) and amyotrophic lateral sclerosis (ALS4) are neurological disorders caused by mutations in the gene encoding for senataxin (SETX), a putative RNA:DNA helicase involved in transcription and in the maintenance of genome integrity. Here, using ChIP followed by high throughput sequencing (ChIP-seq), we report that senataxin is recruited at DNA double-strand breaks (DSBs) when they occur in transcriptionally active loci. Genome-wide mapping unveiled that RNA:DNA hybrids accumulate on DSB-flanking chromatin but display a narrow, DSB-induced, depletion near DNA ends coinciding with senataxin binding. Although neither required for resection nor for timely repair of DSBs, senataxin was found to promote Rad51 recruitment, to minimize illegitimate rejoining of distant DNA ends and to sustain cell viability following DSB production in active genes. Our data suggest that senataxin functions at DSBs in order to limit translocations and ensure cell viability, providing new insights on AOA2/ALS4 neuropathies.
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PMID:Senataxin resolves RNA:DNA hybrids forming at DNA double-strand breaks to prevent translocations. 2941 69


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