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Nonsense suppression

Juexin Wang, Dingding Shen, Geqing Xia, Wangzhen Shen, Robert L Macdonald, Dong Xu, Jing-Qiong Kang
Mutations in GABAA receptor subunit genes are frequently associated with epilepsy, and nonsense mutations in GABRG2 are associated with several epilepsy syndromes including childhood absence epilepsy, generalized tonic clonic seizures and the epileptic encephalopathy, Dravet syndrome. The molecular basis for the phenotypic heterogeneity of mutations is unclear. Here we focused on three nonsense mutations in GABRG2 (GABRG2(R136*), GABRG2(Q390*) and GABRG2(W429*)) associated with epilepsies of different severities...
October 20, 2016: Scientific Reports
Andrew G Matveenko, Polina B Drozdova, Mikhail V Belousov, Svetlana E Moskalenko, Stanislav A Bondarev, Yury A Barbitoff, Anton A Nizhnikov, Galina A Zhouravleva
[PSI(+) ] is the prion form of the translation termination factor Sup35 (eRF3); [PSI(+) ] strains display nonsense suppression. Another prion-like element, [ISP(+) ], is linked to antisuppression in a specific background. Transcriptional regulator Sfp1 was shown to be responsible for [ISP(+) ] propagation. In this work, we identified SFP1 as a multicopy inducer of [PSI(+) ]-dependent lethality. Sfp1 is likely to up-regulate transcription of genes encoding release factors; however, its overproduction increases Sup35, but not Sup45 protein level...
October 12, 2016: Genes to Cells: Devoted to Molecular & Cellular Mechanisms
John D Lueck, Adam L Mackey, Daniel T Infield, Jason D Galpin, Jing Li, Benoît Roux, Christopher A Ahern
C-type inactivation of potassium channels fine-tunes the electrical signaling in excitable cells through an internal timing mechanism that is mediated by a hydrogen bond network in the channels' selectively filter. Previously, (Pless, 2013) we used nonsense suppression to highlight the role of the conserved Trp434-Asp447 indole hydrogen bond in Shaker potassium channels with a non-hydrogen bonding homologue of tryptophan, Ind. Here, molecular dynamics simulations indicate that the Trp434Ind hydrogen bonding partner, Asp447, unexpectedly 'flips out' towards the extracellular environment, allowing water to penetrate the space behind the selectivity filter while simultaneously reducing the local negative electrostatic charge...
October 6, 2016: ELife
Bijoyita Roy, Westley J Friesen, Yuki Tomizawa, John D Leszyk, Jin Zhuo, Briana Johnson, Jumana Dakka, Christopher R Trotta, Xiaojiao Xue, Venkateshwar Mutyam, Kim M Keeling, James A Mobley, Steven M Rowe, David M Bedwell, Ellen M Welch, Allan Jacobson
A premature termination codon (PTC) in the ORF of an mRNA generally leads to production of a truncated polypeptide, accelerated degradation of the mRNA, and depression of overall mRNA expression. Accordingly, nonsense mutations cause some of the most severe forms of inherited disorders. The small-molecule drug ataluren promotes therapeutic nonsense suppression and has been thought to mediate the insertion of near-cognate tRNAs at PTCs. However, direct evidence for this activity has been lacking. Here, we expressed multiple nonsense mutation reporters in human cells and yeast and identified the amino acids inserted when a PTC occupies the ribosomal A site in control, ataluren-treated, and aminoglycoside-treated cells...
October 4, 2016: Proceedings of the National Academy of Sciences of the United States of America
Ekaterina Dzyubak, Mee-Ngan F Yap
Members of the Erm methyltransferase family modify 23S rRNA of the bacterial ribosome and render cross-resistance to macrolides and multiple distantly related antibiotics. Previous studies have shown that the expression of erm is activated when a macrolide-bound ribosome stalls the translation of the leader peptide preceding the co-transcribed erm Ribosome stalling is thought to destabilize the inhibitory stem-loop mRNA structure and exposes the erm Shine-Dalgarno (SD) sequence for translational initiation...
September 19, 2016: Antimicrobial Agents and Chemotherapy
Alice Luddi, Laura Crifasi, Angela Capaldo, Paola Piomboni, Elvira Costantino-Ceccarini
Krabbe's disease (KD) is a degenerative lysosomal storage disease resulting from deficiency of β-galactocerebrosidase activity. Over 100 mutations are known to cause the disease, and these usually occur in compound heterozygote patterns. In affected patients, nonsense mutations leading to a nonfunctional enzyme are often found associated with other mutations. The twitcher mouse is a naturally occurring model of KD, containing in β-galactocerebrosidase a premature stop codon, W339X. Recent studies have shown that selected compounds may induce the ribosomal bypass of premature stop codons without affecting the normal termination codons...
November 2016: Journal of Neuroscience Research
Jean K Mah
Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy in childhood. It is caused by mutations of the DMD gene, leading to progressive muscle weakness, loss of independent ambulation by early teens, and premature death due to cardiorespiratory complications. The diagnosis can usually be made after careful review of the history and examination of affected boys presenting with developmental delay, proximal weakness, and elevated serum creatine kinase, plus confirmation by muscle biopsy or genetic testing...
2016: Neuropsychiatric Disease and Treatment
Ningning Dang, Xiaoli Ma, Xianguang Meng, Liguo An, Shuguang Pang
The aim of the present study was to investigate the impact of filaggrin knockdown on the function of normal human epidermal keratinocytes (NHEKs). Filaggrin expression levels in NHEKs were knocked down by lentivirus (LV) encoding small hairpin RNA (shRNA), with control cells infected with nonsense shRNA or not infected. Cell migration and invasion were assayed using Transwell inserts, cell adhesion and proliferation by the Cell Counting kit‑8 assay, and apoptosis and cell cycle progression by flow cytometry...
September 2016: Molecular Medicine Reports
Kairong Li, Ashley N Turner, Min Chen, Stephanie N Brosius, Trenton R Schoeb, Ludwine M Messiaen, David M Bedwell, Kurt R Zinn, Corina Anastasaki, David H Gutmann, Bruce R Korf, Robert A Kesterson
Neurofibromatosis type 1 (NF1) is a common genetic disorder characterized by the occurrence of nerve sheath tumors and considerable clinical heterogeneity. Some translational studies have been limited by the lack of animal models available for assessing patient-specific mutations. In order to test therapeutic approaches that might restore function to the mutated gene or gene product, we developed mice harboring NF1 patient-specific mutations including a nonsense mutation (c.2041C>T; p.Arg681*) and a missense mutation (c...
July 1, 2016: Disease Models & Mechanisms
Yi Jin, Fang Zhang, Zhenfa Ma, Zhuqing Ren
BACKGROUND: Nonsense-mediated mRNA decay (NMD) is a RNA quality surveillance system for eukaryotes. It prevents cells from generating deleterious truncated proteins by degrading abnormal mRNAs that harbor premature termination codon (PTC). However, little is known about the molecular regulation mechanism underlying the inhibition of NMD by microRNAs. RESULTS: The present study demonstrated that miR-433 was involved in NMD pathway via negatively regulating SMG5. We provided evidence that (1) overexpression of miR-433 significantly suppressed the expression of SMG5 (P < 0...
2016: BMC Molecular Biology
Markus Winter, Dmitri Lodygin, Berlinda Verdoodt, Heiko Hermeking
The p53-inducible cell cycle regulator 14-3-3σ exhibits tumor suppressive functions and is highly expressed in differentiating layers of the epidermis and hair follicles. 14-3-3σ/SFN/stratifin is frequently silenced in human epithelial cancers, and experimental down-regulation of 14-3-3σ expression immortalizes primary human keratinocytes. In the repeated-epilation (ER) mouse model, a heterozygous nonsense mutation of 14-3-3σ causes repeated hair-loss, hyper-proliferative epidermis, and spontaneous development of papillomas and squamous cell carcinomas in aging mice...
July 7, 2016: Oncotarget
Ivana Pibiri, Laura Lentini, Marco Tutone, Raffaella Melfi, Andrea Pace, Aldo Di Leonardo
Ataluren, also known as PTC124, is a 5-(fluorophenyl)-1,2,4-oxadiazolyl-benzoic acid suggested to suppress nonsense mutations by readthrough of premature stop codons in the mRNA. Potential interaction of PTC124 with mRNA has been recently studied by molecular dynamics simulations highlighting the importance of H-bonding and stacking π-π interactions. A series of non-acidic analogues of PTC124 were selected from a large database via a ligand-based virtual screening approach. Eight of them were synthesized and tested for their readthrough activity using the Fluc reporter harboring the UGA premature stop codon...
October 21, 2016: European Journal of Medicinal Chemistry
(no author information available yet)
Inflammatory myofibroblastic tumors (IMT) harbor mutations in nonsense-mediated RNA decay gene UPF1.
August 2016: Cancer Discovery
Jing-Qiong Kang, Robert L Macdonald
OBJECTIVE: In this review article, we focus on the molecular pathogenic basis for genetic generalized epilepsies associated with mutations in the inhibitory γ-aminobutyric acid (GABAA) receptor γ2 subunit gene, GABRG2 (OMIM 137164), an established epilepsy gene. OBSERVATIONS: The γ-aminobutyric acid (GABAA) receptor γ2 subunit gene, GABRG2, is abundantly expressed in the mammalian brain, and its encoded γ2 subunit is assembled into αβγ2 receptors, which are the major GABAA receptor isoforms in the brain...
August 1, 2016: JAMA Neurology
Mariya Moosajee, Dhani Tracey-White, Matthew Smart, Marla Weetall, Simona Torriano, Vasiliki Kalatzis, Lyndon da Cruz, Peter Coffey, Andrew R Webster, Ellen Welch
Choroideremia (CHM) is an X-linked chorioretinal dystrophy that is caused by mutations within a single gene, CHM Currently no effective treatment exists for these patients. Since over 30% of patients harbour nonsense mutations in CHM, nonsense suppression therapy using translational readthrough inducing drugs (TRIDs) may provide functional rescue of REP1, thus attenuating progressive sight loss. Here, we employed two CHM model systems to systematically test the efficacy and safety of ataluren (PTC124) and its novel analog PTC-414: 1) the chm(ru848) zebrafish, the only nonsense mutation animal model of CHM harbouring a TAA nonsense mutation, and 2) a primary human fibroblast cell line from a CHM patient harbouring a TAG nonsense mutation...
June 21, 2016: Human Molecular Genetics
Xuhua Tang, Yiping Zhu, Stacey L Baker, Matthew W Bowler, Benjamin Jieming Chen, Chen Chen, J Robert Hogg, Stephen P Goff, Haiwei Song
Retroviral reverse transcriptase (RT) of Moloney murine leukemia virus (MoMLV) is expressed in the form of a large Gag-Pol precursor protein by suppression of translational termination in which the maximal efficiency of stop codon read-through depends on the interaction between MoMLV RT and peptidyl release factor 1 (eRF1). Here, we report the crystal structure of MoMLV RT in complex with eRF1. The MoMLV RT interacts with the C-terminal domain of eRF1 via its RNase H domain to sterically occlude the binding of peptidyl release factor 3 (eRF3) to eRF1...
2016: Nature Communications
Chih-Hong Lou, Jennifer Dumdie, Alexandra Goetz, Eleen Y Shum, David Brafman, Xiaoyan Liao, Sergio Mora-Castilla, Madhuvanthi Ramaiah, Heidi Cook-Andersen, Louise Laurent, Miles F Wilkinson
Nonsense-mediated RNA decay (NMD) is a highly conserved pathway that selectively degrades specific subsets of RNA transcripts. Here, we provide evidence that NMD regulates early human developmental cell fate. We found that NMD factors tend to be expressed at higher levels in human pluripotent cells than in differentiated cells, raising the possibility that NMD must be downregulated to permit differentiation. Loss- and gain-of-function experiments in human embryonic stem cells (hESCs) demonstrated that, indeed, NMD downregulation is essential for efficient generation of definitive endoderm...
June 14, 2016: Stem Cell Reports
Shehrazade Dahimene, Karen M Page, Manuela Nieto-Rostro, Wendy S Pratt, Marianna D'Arco, Annette C Dolphin
Episodic ataxia 2 (EA2) is an autosomal dominant disorder caused by mutations in the gene CACNA1A that encodes the pore-forming CaV2.1 calcium channel subunit. The majority of EA2 mutations reported so far are nonsense or deletion/insertion mutations predicted to form truncated proteins. Heterologous expression of wild-type CaV2.1, together with truncated constructs that mimic EA2 mutants, significantly suppressed wild-type calcium channel function, indicating that the truncated protein produces a dominant-negative effect (Jouvenceau et al...
September 2016: Neurobiology of Disease
Hiroki Ohara, Toru Nabika
We previously identified a nonsense mutation in the stromal interaction molecule-1 (Stim1) resulting in expression of a truncated STIM1 in the stroke-prone spontaneously hypertensive rat (SHRSP). In this study, we evaluated activity of the store-operated Ca(2+)-entry (SOCE) regulated by STIM1 to clarify putative functional abnormalities of the truncated STIM1. As a result, reduced SOCE activity resulting in suppression of cyclooxygenase-2 expression induced by SOCE was found in cultured astrocytes with the truncated STIM1 when compared with those with the wild-type...
August 5, 2016: Biochemical and Biophysical Research Communications
X Wang, H A Yang, X N Wang, Y F Du
The most significant pathological feature of Parkinson's disease (PD) is the progressive degeneration of dopaminergic (DA) neurons in the substantia nigra. Currently, available treatments for PD cannot prevent the loss of DA neurons. Tyrosine hydroxylase (TH) expressed in substantia nigra neurons catalyzes the conversion of tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA), which is the rate-limiting step of DA biosynthesis. Major reasons for PD occurrence include decreased TH activity in the substantia nigra and secondary DA suppression...
2016: Genetics and Molecular Research: GMR
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