scholarly journals Structural Analysis and Spatiotemporal Expression of Atxn1 Genes in Zebrafish Embryos and Larvae

2021 ◽  
Vol 22 (21) ◽  
pp. 11348
Author(s):  
Franz Vauti ◽  
Viktoria Vögele ◽  
Isabel Deppe ◽  
Susanne T. Hahnenstein ◽  
Reinhard W. Köster
Keyword(s):  
Larval Development ◽  
Disease Modeling ◽  
Expression Patterns ◽  
Family Members ◽  
Cag Repeats ◽  
Spinocerebellar Ataxia Type ◽  
Spinocerebellar Ataxias ◽  
Cerebellar Diseases ◽  
Genetic Structures ◽  
Relationship Of

Zebrafish have come into focus to model cerebellar diseases such as spinocerebellar ataxias (SCAs), which is caused by an expansion of translated CAG repeats in several unrelated genes. In spinocerebellar ataxia type 1 (SCA1), gain-of-function in the mutant ATXN1 contributes to SCA1’s neuropathy. Human ATXN1 and its paralog ATXN1L are chromatin-binding factors, act as transcriptional repressors, and have similar expression patterns. However, little is known about atxn1 genes in zebrafish. Recently, two family members, atxn1a and atxn1b, were identified as duplicate orthologs of ATXN1, as was atxn1l, the ortholog of ATXN1L. In this study, we analyzed the phylogenetic relationship of the atxn1 family members in zebrafish, compared their genetic structures, and verified the predicted transcripts by both RT-PCR and whole-mount in situ hybridization. All three genes, atxn1a, atxn1b, and atxn1l, show overlapping, but also distinct, expression domains during embryonic and larval development. While atxn1a and atxn1l display similar spatiotemporal embryonic expression, atxn1b expression is initiated during the onset of brain development and is predominantly expressed in the cerebellum throughout zebrafish development. These results provide new insights into atxn1 genes and their expression patterns in zebrafish during embryonic and late-larval development and may contribute importantly to future experiments in disease modeling of SCAs.

scholarly journals Genetic Modeling of the Neurodegenerative Disease Spinocerebellar Ataxia Type 1 in Zebrafish

2021 ◽  
Vol 22 (14) ◽  
pp. 7351
Author(s):  
Mohamed A. Elsaey ◽  
Kazuhiko Namikawa ◽  
Reinhard W. Köster
Keyword(s):  
Spinocerebellar Ataxia ◽  
Cag Repeats ◽  
Spinocerebellar Ataxia Type ◽  
Spinocerebellar Ataxias ◽  
Spinocerebellar Ataxia Type 1 ◽  
Reporter Protein ◽  
Fluorescent Reporter ◽  
Larval Stages

Dominant spinocerebellar ataxias (SCAs) are progredient neurodegenerative diseases commonly affecting the survival of Purkinje cells (PCs) in the human cerebellum. Spinocerebellar ataxia type 1 (SCA1) is caused by the mutated ataxin1 (Atx1) gene product, in which a polyglutamine stretch encoded by CAG repeats is extended in affected SCA1 patients. As a monogenetic disease with the Atx1-polyQ protein exerting a gain of function, SCA1 can be genetically modelled in animals by cell type-specific overexpression. We have established a transgenic PC-specific SCA1 model in zebrafish coexpressing the fluorescent reporter protein mScarlet together with either human wild type Atx1[30Q] as control or SCA1 patient-derived Atx1[82Q]. SCA1 zebrafish display an age-dependent PC degeneration starting at larval stages around six weeks postfertilization, which continuously progresses during further juvenile and young adult stages. Interestingly, PC degeneration is observed more severely in rostral than in caudal regions of the PC population. Although such a neuropathology resulted in no gross locomotor control deficits, SCA1-fish with advanced PC loss display a reduced exploratory behaviour. In vivo imaging in this SCA1 model may help to better understand such patterned PC death known from PC neurodegeneration diseases, to elucidate disease mechanisms and to provide access to neuroprotective compound characterization in vivo.

Cerebellar ataxia and ocular conjunctival telangiectasia: Look again

2020 ◽  
pp. 10.1212/CPJ.0000000000000977
Author(s):  
Matheus Gomes Ferreira ◽  
Fábio A. Nascimento ◽  
Hélio A. G. Teive
Keyword(s):  
Cerebellar Ataxia ◽  
Ataxia Telangiectasia ◽  
Cag Repeats ◽  
Spinocerebellar Ataxia Type ◽  
Spinocerebellar Ataxias ◽  
Spinocerebellar Ataxia Type 3 ◽  
Serum Alpha Fetoprotein ◽  
Diagnostic Hypothesis ◽  
Type 3

A 14-year-old boy presented with progressive incoordination and cognitive issues. Family history was negative for any neurological condition. Examination revealed cerebellar ataxia and cognitive impairment as well as prominent ocular conjunctival telangiectasia (figure), which made ataxia-telangiectasia, a recessive disorder, a plausible diagnostic hypothesis. Serum alpha-fetoprotein levels were however normal. At follow-up, he was accompanied by his father, who was found to have significant gait ataxia – warranting genetic testing to assess for an autosomal dominant spinocerebellar ataxias. Abnormal CAG repeats in the ATXN3 gene were identified in the pathogenic range(31/52 CAG repeats) consistent with spinocerebellar ataxia type 3/ Machado-Joseph disease (SCA3). Ocular conjunctival telangiectasia can be found in different diseases, including ataxia-telangiectasia (ATM syndrome), generalized essential telangiectasia, with conjunctival involvement, and hemorrhagic telangiectasia of Rendu-Osler, among others1,2. Ocular conjunctival telangiectasia can be found in association with cerebellar ataxia, even though they may not share a common cause.

scholarly journals TGM6 L517W is not a pathogenic variant for spinocerebellar ataxia type 35

2020 ◽  
Vol 6 (3) ◽  
pp. e424
Author(s):  
Yanxing Chen ◽  
Dengchang Wu ◽  
Benyan Luo ◽  
Guohua Zhao ◽  
Kang Wang
Keyword(s):  
Spinocerebellar Ataxia ◽  
Brain Mri ◽  
Family Members ◽  
Cag Repeat ◽  
Cag Repeats ◽  
Spinocerebellar Ataxia Type ◽  
Healthy Individuals ◽  
Normal Range ◽  
Repeat Number ◽  
Whole Exome

ObjectiveTo investigate the pathogenicity of the TGM6 variant for spinocerebellar ataxia 35 (SCA35), which was previously reported to be caused by pathogenic mutations in the gene TGM6.MethodsNeurologic assessment and brain MRI were performed to provide detailed description of the phenotype. Whole-exome sequencing and dynamic mutation analysis were performed to identify the genotype.ResultsThe proband, presenting with myoclonic epilepsy, cognitive decline, and ataxia, harbored both the TGM6 p.L517W variant and expanded CAG repeats in gene ATN1. Further analysis of the other living family members in this pedigree revealed that the CAG repeat number was expanded in all the patients and within normal range in all the unaffected family members. However, the TGM6 p.L517W variant was absent in 2 affected family members, but present in 3 healthy individuals.ConclusionsThe nonsegregation of the TGM6 variant with phenotype does not support this variant as the disease-causing gene in this pedigree, questioning the pathogenicity of TGM6 in SCA35.

scholarly journals Use of single guided Cas9 nickase to facilitate precise and efficient genome editing in human iPSCs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pan P. Li ◽  
Russell L. Margolis
Keyword(s):  
Genome Editing ◽  
Disease Modeling ◽  
Neurodegenerative Disorder ◽  
Cag Repeat ◽  
Spinocerebellar Ataxia Type ◽  
End Joining ◽  
Human Ipscs ◽  
Non Homologous End Joining ◽  
Transient Overexpression ◽  
Donor Template

AbstractCas9 nucleases permit rapid and efficient generation of gene-edited cell lines. However, in typical protocols, mutations are intentionally introduced into the donor template to avoid the cleavage of donor template or re-cleavage of the successfully edited allele, compromising the fidelity of the isogenic lines generated. In addition, the double-stranded breaks (DSBs) used for editing can introduce undesirable “on-target” indels within the second allele of successfully modified cells via non-homologous end joining (NHEJ). To address these problems, we present an optimized protocol for precise genome editing in human iPSCs that employs (1) single guided Cas9 nickase to generate single-stranded breaks (SSBs), (2) transient overexpression of BCL-XL to enhance survival post electroporation, and (3) the PiggyBac transposon system for seamless removal of dual selection markers. We have used this method to modify the length of the CAG repeat contained in exon 7 of PPP2R2B. When longer than 43 triplets, this repeat causes the neurodegenerative disorder spinocerebellar ataxia type 12 (SCA12); our goal was to seamlessly introduce the SCA12 mutation into a human control iPSC line. With our protocol, ~ 15% of iPSC clones selected had the desired gene editing without “on target” indels or off-target changes, and without the deliberate introduction of mutations via the donor template. This method will allow for the precise and efficient editing of human iPSCs for disease modeling and other purposes.

Sequence variation and size ranges of CAG repeats in the Machado-Joseph disease, spinocerebellar ataxia type 1 and androgen receptor genes

1995 ◽  
Vol 4 (9) ◽  
pp. 1585-1590 ◽  
Author(s):  
David C. Rubinsztein ◽  
Jayne Leggo ◽  
Gerhard A. Coetzee ◽  
Ryan A. Irvine ◽  
Michael Buckley ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Spinocerebellar Ataxia ◽  
Sequence Variation ◽  
Cag Repeats ◽  
Spinocerebellar Ataxia Type ◽  
Spinocerebellar Ataxia Type 1 ◽  
Machado Joseph Disease

Bovine CACNA1A gene and comparative analysis of the CAG repeats associated to human spinocerebellar ataxia type-6

Gene ◽  
2006 ◽  
Vol 380 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Eva Andrés-Mateos ◽  
Jesús Cruces ◽  
Jaime Renart ◽  
Luisa M. Solís-Garrido ◽  
Rocío Serantes ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Spinocerebellar Ataxia ◽  
Cag Repeats ◽  
Spinocerebellar Ataxia Type ◽  
Spinocerebellar Ataxia Type 6 ◽  
Cacna1a Gene

scholarly journals Homozygous spinocerebellar ataxia type 3 in China: a case report

2021 ◽  
Vol 49 (6) ◽  
pp. 030006052110213
Author(s):  
Yuchao Chen ◽  
Dan Li ◽  
Minger Wei ◽  
Menglu Zhou ◽  
Linan Zhang ◽  
...  
Keyword(s):  
Spinocerebellar Ataxia ◽  
Clinical Phenotype ◽  
Gene Dosage ◽  
Cag Repeat ◽  
Cag Repeats ◽  
Spinocerebellar Ataxia Type ◽  
Contraction Pattern ◽  
Spinocerebellar Ataxia Type 3 ◽  
Type 3 ◽  
Stable Transmission

Spinocerebellar ataxia type 3 (SCA3) is a neurodegenerative disease caused by a heterozygous CAG repeat expansion in the ataxin 3 gene ( ATXN3). However, patients with homozygous SCA3 carrying expanded CAG repeats in both alleles of ATXN3 are extremely rare. Herein, we present a case of a 50-year-old female who had homozygous SCA3 with expansion of 62/62 repeats. Segregation analysis of the patient’s family showed both a contraction pattern of CAG repeat length and stable transmission. The present case demonstrated an earlier onset and more severe clinical phenotype than that seen in heterozygous individuals, suggesting that the gene dosage enhances disease severity.

scholarly journals The controlling power of royal family members on the board of directors and audit committee effectiveness

Accounting ◽  
2021 ◽  
pp. 987-992
Author(s):  
Khaled Salmen Aljaaidi ◽  
Abdulaziz Alothman ◽  
Raj Bahadur Sharma ◽  
Omar Ali Bagais
Keyword(s):  
Board Of Directors ◽  
Audit Committee ◽  
Family Members ◽  
Family Ownership ◽  
Marginal Effect ◽  
Governance Mechanism ◽  
Royal Family ◽  
The Board Of Directors ◽  
Corporate Governance Mechanism ◽  
Relationship Of

This paper examines the association of the presence of royal family members on the board of directors with audit committee effectiveness. The sample of this study consists of 444 listed manufactured firms in Saudi Arabia for the period 2012-2019. Using the Pooled OLS regression, the result of the study shows that royal family ownership is associated with audit committee effectiveness, giving support to the substitution hypothesis. The result indicates that members from the royal families are good monitors imposed into the companies' managements as both taking the role of decision makers and owners who may substitute the effectiveness of the audit committee. The presence of royal family members on the board has an alternative for the effectiveness of the audit committee. The marginal effect of audit committee effectiveness as an internal corporate governance mechanism is substituted by the presence of royal family members on the board. This study provides insightful evidence to regulators and policy makers at the company and country levels on the relationship of royal family ownership and audit committee effectiveness.

scholarly journals Tumor-derived extracellular vesicles inhibit HGF/c-Met and EGF/EGFR pathways to accelerate the radiosensitivity of nasopharyngeal carcinoma cells via microRNA-142-5p delivery

2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Changyu Zhu ◽  
Xiaolei Jiang ◽  
Hua Xiao ◽  
Jianmei Guan
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Extracellular Vesicles ◽  
Nude Mice ◽  
Peripheral Blood ◽  
Cell Apoptosis ◽  
Expression Patterns ◽  
Carcinoma Cells ◽  
Luciferase Reporter ◽  
Relationship Of ◽  
Dual Luciferase Reporter Assay

AbstractRadioresistance prevails as one of the largest obstacles in the clinical treatment of nasopharyngeal carcinoma (NPC). Meanwhile, tumor-derived extracellular vesicles (TEVs) possess the ability to manipulate radioresistance in NPC. However, its mechanism remains to be further explored. Therefore, the current study set out to explore the mechanism of microRNA (miR)-142-5p delivered by TEVs in regard to the radiosensitivity of NPC. Firstly, peripheral blood samples were collected from patients with radioresistance and radiosensitivity, followed by RT-qPCR detection of miR-142-5p expression. A dual-luciferase reporter assay was carried out to elucidate the targeting relationship of miR-142-5p with HGF and EGF. In addition, radiotherapy-resistant NPC cell models were established by screening NPC cells with gradient increasing radiation exposure, and co-incubated with EVs isolated from miR-142-5p mimic-transfected NPC cells, followed by overexpression of HGF and EGF. Moreover, cell viability was detected by means of MTS, cell proliferation with a colony formation assay, cell apoptosis with flow cytometry, and expression patterns of related genes with the help of Western blot analysis. NPC xenotransplantation models in nude mice were also established by subcutaneous injection of 5-8FR cells to determine apoptosis, tumorigenicity, and radiosensitivity in nude mice. It was found that miR-142-5p was poorly expressed in peripheral blood from NPC patients with radioresistance. Mechanistic experimentation illustrated that miR-142-5p inversely targeted HGF and EGF to inactivate the HGF/c-Met and EGF/EGFR pathways, respectively. NPC cell apoptosis was observed to be augmented, while their radioresistance and proliferation were restricted by EVs-miR-142-5p or HGF silencing, or EGF silencing. Furthermore, EVs-miR-142-5p inhibited growth and radioresistance and accelerated the apoptosis of radiotherapy-resistant NPC cells in nude mice by inhibiting the HGF/c-Met and EGF/EGFR pathways. Collectively, our findings indicated that TEVs might inhibit the HGF/c-Met and EGF/EGFR pathways by delivering miR-142-5p into radiotherapy-resistant NPC cells to enhance radiosensitivity in NPC.

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