scholarly journals Identification and Functional Analysis of Mutations in the Hypocretin (Orexin) Genes of Narcoleptic Canines

2001 ◽  
Vol 11 (4) ◽  
pp. 531-539
Author(s):  
Marcel Hungs ◽  
Jun Fan ◽  
Ling Lin ◽  
Xiaoyan Lin ◽  
Richard A. Maki ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Novel Mutation ◽  
Disease Onset ◽  
Exon Skipping ◽  
Single Amino Acid ◽  
Membrane Localization ◽  
Loss Of Function ◽  
Hek 293 ◽  
Sporadic Cases ◽  
Multiplex Families

Narcolepsy is a sleep disorder affecting animals and humans. Exon skipping mutations of the Hypocretin/Orexin-receptor-2 (Hcrtr2) gene were identified as the cause of narcolepsy in Dobermans and Labradors. Preprohypocretin (Hcrt) knockout mice have symptoms similar to human and canine narcolepsy. In this study, 11 sporadic cases of canine narcolepsy and two additional multiplex families were investigated for possible Hcrt andHcrtr2 mutations. Sporadic cases have been shown to have more variable disease onset, increased disease severity, and undetectable Hypocretin-1 levels in cerebrospinal fluid. The canine Hcrtlocus was isolated and characterized for this project. Only one novel mutation was identified in these two loci. This alteration results in a single amino acid substitution (E54K) in the N-terminal region of the Hcrtr2 receptor and autosomal recessive transmission in a Dachshund family. Functional analysis of previously-described exon-skipping mutations and of the E54K substitution were also performed using HEK-293 cell lines transfected with wild-type and mutated constructs. Results indicate a truncated Hcrtr2 protein, an absence of proper membrane localization, and undetectable binding and signal transduction for exon-skipping mutated constructs. In contrast, the E54K abnormality was associated with proper membrane localization, loss of ligand binding, and dramatically diminished calcium mobilization on activation of the receptor. These results are consistent with a loss of function for all three mutations. The absence of mutation in sporadic cases also indicates genetic heterogeneity in canine narcolepsy, as reported previously in humans.

Abstract 5672: Novel SCN5A Mutations and SNP in Patients with Brugada Syndrome

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Kazufumi Nakamura ◽  
Daiji Miura ◽  
Kaoru Kobayashi ◽  
Mamoru Ouchida ◽  
Kenji Shimizu ◽  
...  
Keyword(s):  
Brugada Syndrome ◽  
Direct Sequencing ◽  
Single Point ◽  
Point Mutations ◽  
Exon Skipping ◽  
Pcr Analysis ◽  
Nucleotide Polymorphisms ◽  
Loss Of Function ◽  
Patch Clamp Technique ◽  
Hek 293

Background: Sodium channel alpha 5 subunit (SCN5A) mutations are important genetic abnormalities of Brugada syndrome (BS). Here we report novel SCN5A mutations in patients with BS. Methods and Results: Genomic mutations in the SCN5A gene were analyzed by PCR and direct sequencing in 121 patients with BS (119 men and 2 women). Thirteen (11%) of the patients had SCN5A mutation and five (4%) of the patients had single nucleotide polymorphisms (SNP) associated with BS. Eleven patients had single point mutations, one patient had a deletion (1380 del N) and one patient had a mutation within the splicing junction (IVS21+1 g>a). The whole-cell patch clamp technique revealed that four novel mutations (F532C, R814Q, G833R, R878C) showed loss of function, and peak INa of a novel SNP (L1988R) transiently expressed in HEK 293 cells was significantly reduced (P<0.05). RT-PCR analysis revealed that the intronic mutation (IVS21+1 g>a) resulted in exon 21 deletion of SCN5A in cardiac biopsy specimens from the patient (Figure ). Conclusions: We detected five novel SCN5A mutations (1380 del N, F532C, R814Q, G833R, R878C) and a novel disease-associated SNP (L1988R) in patients with BS. We showed a novel analysis of splicing mutation (IVS21+1 g>a) that resulted in exon skipping in the heart.

Abstract P184: Novel SCN5A Mutations and SNP in Patients with Brugada Syndrome

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Kazufumi Nakamura ◽  
Daiji Miura ◽  
Kaoru Kobayashi ◽  
Mamoru Ouchida ◽  
Kenji Shimizu ◽  
...  
Keyword(s):  
Brugada Syndrome ◽  
Direct Sequencing ◽  
Single Point ◽  
Point Mutations ◽  
Exon Skipping ◽  
Pcr Analysis ◽  
Nucleotide Polymorphisms ◽  
Loss Of Function ◽  
Patch Clamp Technique ◽  
Hek 293

Background: Sodium channel alpha 5 subunit (SCN5A) mutations are important genetic abnormalities of Brugada syndrome (BS). Here we report novel SCN5A mutations in patients with BS. Methods and Results: Genomic mutations in the SCN5A gene were analyzed by PCR and direct sequencing in 121 patients with BS (119 men and 2 women). Thirteen (11%) of the patients had SCN5A mutation and five (4%) of the patients had single nucleotide polymorphisms (SNP) associated with BS. Eleven patients had single point mutations, one patient had a deletion (1380 del N) and one patient had a mutation within the splicing junction (IVS21+1 g>a). The whole-cell patch clamp technique revealed that four novel mutations (F532C, R814Q, G833R, R878C) showed loss of function, and peak INa of a novel SNP (L1988R) transiently expressed in HEK 293 cells was significantly reduced (P<0.05). RT-PCR analysis revealed that the intronic mutation (IVS21+1 g>a) resulted in exon 21 deletion of SCN5A in cardiac biopsy specimens from the patient (Figure ). Conclusions: We detected five novel SCN5A mutations (1380 del N, F532C, R814Q, G833R, R878C) and a novel disease-associated SNP (L1988R) in patients with BS. We showed a novel analysis of splicing mutation (IVS21+1 g>a) that resulted in exon skipping in the heart.

scholarly journals Differences in a Single Extracellular Residue Underlie Adhesive Functions of Two Zebrafish Aqp0s

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 2005
Author(s):  
Irene Vorontsova ◽  
James E. Hall ◽  
Thomas F. Schilling ◽  
Noriaki Nagai ◽  
Yosuke Nakazawa
Keyword(s):  
Cell Adhesion ◽  
Single Amino Acid ◽  
Amino Acid Difference ◽  
Adhesion Assay ◽  
Loss Of Function ◽  
Adhesive Properties ◽  
The Difference ◽  
In Vitro Adhesion ◽  
Cell To Cell Adhesion

Aquaporin 0 (AQP0) is the most abundant lens membrane protein, and loss of function in human and animal models leads to cataract formation. AQP0 has several functions in the lens including water transport and adhesion. Since lens optics rely on strict tissue architecture achieved by compact cell-to-cell adhesion between lens fiber cells, understanding how AQP0 contributes to adhesion would shed light on normal lens physiology and pathophysiology. We show in an in vitro adhesion assay that one of two closely related zebrafish Aqp0s, Aqp0b, has strong auto-adhesive properties while Aqp0a does not. The difference appears to be largely due to a single amino acid difference at residue 110 in the extracellular C-loop, which is T in Aqp0a and N in Aqp0b. Similarly, P110 is the key residue required for adhesion in mammalian AQP0, highlighting the importance of residue 110 in AQP0 cell-to-cell adhesion in vertebrate lenses as well as the divergence of adhesive and water permeability functions in zebrafish duplicates.

scholarly journals A Novel Mutation of ATP7B Gene in a Case of Wilson Disease

Medicina ◽  
2021 ◽  
Vol 57 (2) ◽  
pp. 123
Author(s):  
Cigdem Yuce Kahraman ◽  
Ali Islek ◽  
Abdulgani Tatar ◽  
Özlem Özdemir ◽  
Adil Mardinglu ◽  
...  
Keyword(s):  
Wilson Disease ◽  
Novel Mutation ◽  
Molecular Genetic ◽  
Molecular Genetic Analysis ◽  
Compound Heterozygous ◽  
Atp7b Gene ◽  
Loss Of Function ◽  
Clinical Presentations ◽  
The Family ◽  
The Brain

Wilson disease (WD) (OMIM# 277900) is an autosomal recessive inherited disorder characterized by excess copper (Cu) storage in different human tissues, such as the brain, liver, and the corneas of the eyes. It is a rare disorder that occurs in approximately 1 in 30,000 individuals. The clinical presentations of WD are highly varied, primarily consisting of hepatic and neurological conditions. WD is caused by homozygous or compound heterozygous mutations in the ATP7B gene. The diagnosis of the disease is complicated because of its heterogeneous phenotypes. The molecular genetic analysis encourages early diagnosis, treatment, and the opportunity to screen individuals at risk in the family. In this paper, we reported a case with a novel, hotspot-located mutation in WD. We have suggested that this mutation in the ATP7B gene might contribute to liver findings, progressing to liver failure with a loss of function effect. Besides this, if patients have liver symptoms in childhood and/or are children of consanguineous parents, WD should be considered during the evaluation of the patients.

scholarly journals Clinical, Genetics, and Bioinformatic Characterization of Mutations Affecting an Essential Region of PLS3 in Patients with BMND18

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Ting Chen ◽  
Haiying Wu ◽  
Chenxi Zhang ◽  
Jiarong Feng ◽  
Linqi Chen ◽  
...  
Keyword(s):  
Novel Mutation ◽  
Homology Modelling ◽  
Gene Sequencing ◽  
Bioinformatic Analysis ◽  
Actin Binding ◽  
Clinical Genetics ◽  
Loss Of Function ◽  
Mineral Density ◽  
Trait Locus ◽  
The Impact

Background. Bone mineral density quantitative trait locus 18 (BMND18, OMIM #300910) is a type of early-onset osteogenesis imperfecta (OI) caused by loss-of-function mutations in the PLS3 gene, which encodes plastin-3, a key protein in the formation of actin bundles throughout the cytoskeleton. Here, we report a patient with PLS3 mutation caused BMND18 and evaluated all the reported disease-causing mutations by bioinformatic analysis. Methods. Targeted gene sequencing was performed to find the disease-causing mutation in our patient. Bioinformatic analyses mainly including homology modelling and molecular dynamics stimulation were conducted to explore the impact of the previously reported mutations on plastin-3. Results. Gene sequencing showed a novel nonsense mutation (c.745G > T, p.E249X), which locates at a highly conserved region containing residues p.240–266 (LOOP-1) in the PLS3 gene. Further bioinformatic analyses of the previously reported mutations revealed that LOOP-1 is predicted to physically connect the calponin-homology 1 (CH1) and CH2 domains of the ABD1 fragment and spatially locates within the interface of ABD1 and ABD2. It is crucial to the conformation transition and actin-binding function of plastin-3. Conclusions. This report identified a novel mutation that truncates the PLS3 gene. Moreover, bioinformatic analyses of the previous reported mutations in PLS3 gene lead us to find a critical LOOP-1 region of plastin-3 mutations at which may be detrimental to the integral conformation of plastin-3 and thus affect its binding to actin filament.

scholarly journals Goα Regulates Volatile Anesthetic Action in Caenorhabditis elegans

Genetics ◽  
2001 ◽  
Vol 158 (2) ◽  
pp. 643-655 ◽  
Author(s):  
Bruno van Swinderen ◽  
Laura B Metz ◽  
Laynie D Shebester ◽  
Jane E Mendel ◽  
Paul W Sternberg ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Novel Mutation ◽  
Volatile Anesthetic ◽  
Loss Of Function ◽  
Wild Type ◽  
Α Subunit ◽  
C Elegans ◽  
Missense Mutant ◽  
Anesthetic Action ◽  
Mutant Phenotypes

Abstract To identify genes controlling volatile anesthetic (VA) action, we have screened through existing Caenorhabditis elegans mutants and found that strains with a reduction in Go signaling are VA resistant. Loss-of-function mutants of the gene goa-1, which codes for the α-subunit of Go, have EC50s for the VA isoflurane of 1.7- to 2.4-fold that of wild type. Strains overexpressing egl-10, which codes for an RGS protein negatively regulating goa-1, are also isoflurane resistant. However, sensitivity to halothane, a structurally distinct VA, is differentially affected by Go pathway mutants. The RGS overexpressing strains, a goa-1 missense mutant found to carry a novel mutation near the GTP-binding domain, and eat-16(rf) mutants, which suppress goa-1(gf) mutations, are all halothane resistant; goa-1(null) mutants have wild-type sensitivities. Double mutant strains carrying mutations in both goa-1 and unc-64, which codes for a neuronal syntaxin previously found to regulate VA sensitivity, show that the syntaxin mutant phenotypes depend in part on goa-1 expression. Pharmacological assays using the cholinesterase inhibitor aldicarb suggest that VAs and GOA-1 similarly downregulate cholinergic neurotransmitter release in C. elegans. Thus, the mechanism of action of VAs in C. elegans is regulated by Goα, and presynaptic Goα-effectors are candidate VA molecular targets.

scholarly journals The Interplay of Mitophagy and Inflammation in Duchenne Muscular Dystrophy

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 648
Author(s):  
Andrea L. Reid ◽  
Matthew S. Alexander
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Mitochondrial Dysfunction ◽  
Disease Onset ◽  
Exon Skipping ◽  
Dystrophin Gene ◽  
Muscle Disease ◽  
Mitochondrial Morphology ◽  
Gene Therapies ◽  
Dystrophin Protein

Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular disease caused by a pathogenic disruption of the DYSTROPHIN gene that results in non-functional dystrophin protein. DMD patients experience loss of ambulation, cardiac arrhythmia, metabolic syndrome, and respiratory failure. At the molecular level, the lack of dystrophin in the muscle results in myofiber death, fibrotic infiltration, and mitochondrial dysfunction. There is no cure for DMD, although dystrophin-replacement gene therapies and exon-skipping approaches are being pursued in clinical trials. Mitochondrial dysfunction is one of the first cellular changes seen in DMD myofibers, occurring prior to muscle disease onset and progresses with disease severity. This is seen by reduced mitochondrial function, abnormal mitochondrial morphology and impaired mitophagy (degradation of damaged mitochondria). Dysfunctional mitochondria release high levels of reactive oxygen species (ROS), which can activate pro-inflammatory pathways such as IL-1β and IL-6. Impaired mitophagy in DMD results in increased inflammation and further aggravates disease pathology, evidenced by increased muscle damage and increased fibrosis. This review will focus on the critical interplay between mitophagy and inflammation in Duchenne muscular dystrophy as a pathological mechanism, as well as describe both candidate and established therapeutic targets that regulate these pathways.

scholarly journals Early-Onset Parkinson Disease Screening in Patients From Nigeria

2021 ◽  
Vol 11 ◽  
Author(s):  
Lukasz M. Milanowski ◽  
Olajumoke Oshinaike ◽  
Benjamin J. Broadway ◽  
Jennifer A. Lindemann ◽  
Alexandra I. Soto-Beasley ◽  
...  
Keyword(s):  
Functional Analysis ◽  
Parkinson Disease ◽  
Neurodegenerative Diseases ◽  
Early Onset ◽  
Local Population ◽  
Age At Onset ◽  
Compound Heterozygous ◽  
Loss Of Function ◽  
African Countries ◽  
Age Related

Introduction: Nigeria is one of the most populated countries in the world; however, there is a scarcity of studies in patients with age-related neurodegenerative diseases, such as Parkinson disease (PD). The aim of this study was to screen patients with PD including a small cohort of early-onset PD (EOPD) cases from Nigeria for PRKN, PINK1, DJ1, SNCA multiplication, and LRRK2 p.G2019S.Methods: We assembled a cohort of 109 Nigerian patients with PD from the four main Nigerian tribes: Yoruba, Igbo, Edo, and Hausa. Fifteen cases [14 from the Yoruba tribe (93.3%)] had EOPD (defined as age-at-onset &lt;50 years). All patients with EOPD were sequenced for the coding regions of PRKN, PINK1, and DJ1. Exon dosage analysis was performed with a multiplex ligation-dependent probe amplification assay, which also included a SNCA probe and LRRK2 p.G2019S. We screened for LRRK2 p.G2019S in the entire PD cohort using a genotyping assay. The PINK1 p.R501Q functional analysis was conducted.Results: In 15 patients with EOPD, 22 variants were observed [PRKN, 9 (40.9%); PINK1, 10 (45.5%); and DJ1, 3 (13.6%)]. Three (13.6%) rare, nonsynonymous variants were identified, but no homozygous or compound heterozygous carriers were found. No exonic rearrangements were present in the three genes, and no carriers of SNCA genomic multiplications or LRRK2 p.G2019S were identified. The PINK1 p.R501Q functional analysis revealed pathogenic loss of function.Conclusion: More studies on age-related neurodegenerative diseases are needed in sub-Saharan African countries, including Nigeria. Population-specific variation may provide insight into the genes involved in PD in the local population but may also contribute to larger studiesperformed in White and Asian populations.

Sign in / Sign up

Export Citation Format

Share Document