scholarly journals Murine knockin model for progranulin-deficient frontotemporal dementia with nonsense-mediated mRNA decay

2018 ◽  
Vol 115 (12) ◽  
pp. E2849-E2858 ◽  
Author(s):  
Andrew D. Nguyen ◽  
Thi A. Nguyen ◽  
Jiasheng Zhang ◽  
Swathi Devireddy ◽  
Ping Zhou ◽  
...  
Keyword(s):  
Frontotemporal Dementia ◽  
Mrna Decay ◽  
Neurodegenerative Disorder ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Mrna Levels ◽  
In Vivo Testing ◽  
Nonsense Mediated Mrna Decay ◽  
Excessive Grooming

Frontotemporal dementia (FTD) is the most common neurodegenerative disorder in individuals under age 60 and has no treatment or cure. Because many cases of FTD result from GRN nonsense mutations, an animal model for this type of mutation is highly desirable for understanding pathogenesis and testing therapies. Here, we generated and characterized GrnR493X knockin mice, which model the most common human GRN mutation, a premature stop codon at arginine 493 (R493X). Homozygous GrnR493X mice have markedly reduced Grn mRNA levels, lack detectable progranulin protein, and phenocopy Grn knockout mice, with CNS microgliosis, cytoplasmic TDP-43 accumulation, reduced synaptic density, lipofuscinosis, hyperinflammatory macrophages, excessive grooming behavior, and reduced survival. Inhibition of nonsense-mediated mRNA decay (NMD) by genetic, pharmacological, or antisense oligonucleotide-based approaches showed that NMD contributes to the reduced mRNA levels in GrnR493X mice and cell lines and in fibroblasts from patients containing the GRNR493X mutation. Moreover, the expressed truncated R493X mutant protein was functional in several assays in progranulin-deficient cells. Together, these findings establish a murine model for in vivo testing of NMD inhibition or other therapies as potential approaches for treating progranulin deficiency caused by the R493X mutation.

Inactivation of RB1 in mantle-cell lymphoma detected by nonsense-mediated mRNA decay pathway inhibition and microarray analysis

Blood ◽  
2007 ◽  
Vol 109 (12) ◽  
pp. 5422-5429 ◽  
Author(s):  
Magda Pinyol ◽  
Silvia Bea ◽  
Laura Plà ◽  
Vincent Ribrag ◽  
Jacques Bosq ◽  
...  
Keyword(s):  
Mantle Cell Lymphoma ◽  
Mrna Decay ◽  
Chromosomal Abnormalities ◽  
Cell Lymphoma ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Homozygous Deletion ◽  
Mantle Cell ◽  
Intragenic Deletions ◽  
Nonsense Mediated Mrna Decay

Abstract Mantle-cell lymphoma (MCL) is genetically characterized by the translocation t(11;14)(q13;q32) and a high number of secondary chromosomal abnormalities. To identify genes inactivated in this lymphoma, we examined 5 MCL cell lines following a strategy previously described in tumors with microsatellite instability that is based on the combined inhibition of the nonsense-mediated mRNA decay pathway and gene-expression profiling. This approach, together with the design of a conservative algorithm for analysis of the results, allowed the identification of 3 genes carrying premature stop codons. These genes were p53 with a mutation previously described in JEKO-1, the leukocyte-derived arginine aminopeptidase (LRAP) gene in REC-1 that showed a new splicing isoform generating a premature stop codon, and RB1 in UPN-1 that contained an intragenic homozygous deletion resulting in a truncated transcript and total loss of protein expression. The new LRAP isoform was detected also in 2 primary MCLs, whereas inactivating intragenic deletions of RB1 were found in the primary tumor from which UPN-1 was derived and 1 additional blastoid MCL. These tumors carried a concomitant inactivation of p53, whereas p16INK4a was wild type. These results indicate for the first time that RB1 may be inactivated in aggressive MCL by intragenic deletions.

scholarly journals New insights into the interplay between the translation machinery and nonsense-mediated mRNA decay factors

2018 ◽  
Vol 46 (3) ◽  
pp. 503-512 ◽  
Author(s):  
Etienne Raimondeau ◽  
Joshua C. Bufton ◽  
Christiane Schaffitzel
Keyword(s):  
Mrna Decay ◽  
Stop Codon ◽  
Translation Termination ◽  
Premature Stop Codon ◽  
Molecular Function ◽  
Translation Machinery ◽  
New Findings ◽  
Nascent Chain ◽  
Nonsense Mediated Mrna Decay

Faulty mRNAs with a premature stop codon (PTC) are recognized and degraded by nonsense-mediated mRNA decay (NMD). Recognition of a nonsense mRNA depends on translation and on the presence of NMD-enhancing or the absence of NMD-inhibiting factors in the 3′-untranslated region. Our review summarizes our current understanding of the molecular function of the conserved NMD factors UPF3B and UPF1, and of the anti-NMD factor Poly(A)-binding protein, and their interactions with ribosomes translating PTC-containing mRNAs. Our recent discovery that UPF3B interferes with human translation termination and enhances ribosome dissociation in vitro, whereas UPF1 is inactive in these assays, suggests a re-interpretation of previous experiments and modification of prevalent NMD models. Moreover, we discuss recent work suggesting new functions of the key NMD factor UPF1 in ribosome recycling, inhibition of translation re-initiation and nascent chain ubiquitylation. These new findings suggest that the interplay of UPF proteins with the translation machinery is more intricate than previously appreciated, and that this interplay quality-controls the efficiency of termination, ribosome recycling and translation re-initiation.

scholarly journals Nonsense mRNA suppression via nonstop decay

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Joshua A Arribere ◽  
Andrew Z Fire
Keyword(s):  
Mrna Decay ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Nonsense Mediated Decay ◽  
Stop Codons ◽  
Nonstop Mrna Decay ◽  
Rna Fragments ◽  
Nonsense Mediated Mrna Decay ◽  
Key Steps

Nonsense-mediated mRNA decay is the process by which mRNAs bearing premature stop codons are recognized and cleared from the cell. While considerable information has accumulated regarding recognition of the premature stop codon, less is known about the ensuing mRNA suppression. During the characterization of a second, distinct translational surveillance pathway (nonstop mRNA decay), we trapped intermediates in nonsense mRNA degradation. We present data in support of a model wherein nonsense-mediated decay funnels into the nonstop decay pathway in Caenorhabditis elegans. Specifically, our results point to SKI-exosome decay and pelota-based ribosome removal as key steps facilitating suppression and clearance of prematurely-terminated translation complexes. These results suggest a model in which premature stop codons elicit nucleolytic cleavage, with the nonstop pathway disengaging ribosomes and degrading the resultant RNA fragments to suppress ongoing expression.

scholarly journals Low tetrahydrobiopterin biosynthetic capacity of human monocytes is caused by exon skipping in 6-pyruvoyl tetrahydropterin synthase

2003 ◽  
Vol 373 (3) ◽  
pp. 681-688 ◽  
Author(s):  
Karin L. LEITNER ◽  
Martina MEYER ◽  
Walter LEIMBACHER ◽  
Anja PETERBAUER ◽  
Susanne HOFER ◽  
...  
Keyword(s):  
Stop Codon ◽  
Premature Stop Codon ◽  
Exon Skipping ◽  
Cell Types ◽  
Mrna Levels ◽  
Human Monocytes ◽  
Reading Frame ◽  
Nonsense Mediated Mrna Decay ◽  
Entire Open Reading Frame ◽  
Different Cell Types

Biosynthesis of (6R)-5,6,7,8-tetrahydro-l-biopterin (H4-biopterin), an essential cofactor for aromatic amino acid hydroxylases and NO synthases, is effectively induced by cytokines in most of the cell types. However, human monocytes/macrophages form only a little H4-biopterin, but release neopterin/7,8-dihydroneopterin instead. Whereas 6-pyruvoyl tetrahydropterin synthase (PTPS) activity, the second enzyme of H4-biopterin biosynthesis, is hardly detectable in these cells, PTPS mRNA levels were comparable with those of cell types containing intact PTPS activity. By screening a THP-1 cDNA library, we identified clones encoding the entire open reading frame (642 bp) as well as clones lacking the 23 bp exon 3, which results in a premature stop codon. Quantification of the two mRNA species in different cell types (blood-derived cells, fibroblasts and endothelial cells) and cell lines showed that the amount of exon-3-containing mRNA is correlated closely to PTPS activity. The ratio of exon-3-containing to exon-3-lacking PTPS mRNA is not affected by differential mRNA stability or nonsense-mediated mRNA decay. THP-1 cells transduced with wild-type PTPS cDNA produced H4-biopterin levels and expressed PTPS activities and protein amounts comparable with those of fibroblasts. We therefore conclude that exon 3 skipping in transcription rather than post-transcriptional mechanisms is a major cause of the low PTPS protein expression observed in human macrophages and related cell types.

scholarly journals In VivoEffects of Leptin-Related Synthetic Peptides on Body Weight and Food Intake in Female ob/obMice: Localization of Leptin Activity to Domains Between Amino Acid Residues 106–140*

Endocrinology ◽  
1997 ◽  
Vol 138 (4) ◽  
pp. 1413-1418 ◽  
Author(s):  
Patricia Grasso ◽  
Matthew C. Leinung ◽  
Stacy P. Ingher ◽  
Daniel W. Lee
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Amino Acid ◽  
Food Intake ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Amino Acid Residues ◽  
Inactive Form ◽  
In Vivo Effects

Abstract In C57BL/6J ob/ob mice, a single base mutation of the ob gene in codon 105 results in the replacement of arginine by a premature stop codon and production of a truncated inactive form of leptin. These observations suggest that leptin activity may be localized, at least in part, to domains distal to amino acid residue 104. To investigate this possibility, we synthesized six overlapping peptide amides corresponding to residues 106–167 of leptin, and examined their effects on body weight and food intake in female C57BL/6J ob/ob mice. When compared with vehicle-injected control mice, weight gain by mice receiving 28 daily 1-mg ip injections of LEP-(106–120), LEP-(116–130), or LEP-(126–140) was significantly (P < 0.01) reduced with no apparent toxicity. Weight gain by mice receiving LEP-(136–150), LEP-(146–160), or LEP-(156–167) was not significantly different from that of vehicle-injected control mice. The effects of LEP-(106–120), LEP-(116–130), or LEP-(126–140) were most pronounced during the first week of peptide treatment. Within 7 days, mice receiving these peptides lost 12.3%, 13.8%, and 9.8%, respectively, of their initial body weights. After 28 days, mice given vehicle alone, LEP-(136–150), LEP-(146–160), or LEP-(156–167) were 14.7%, 20.3%, 25.0%, and 24.8% heavier, respectively, than they were at the beginning of the study. Mice given LEP-(106–120) or LEP-(126–140) were only 1.8% and 4.2% heavier, respectively, whereas mice given LEP-(116–130) were 3.4% lighter. Food intake by mice receiving LEP-(106–120), LEP-(116–130), or LEP-(126–140), but not by mice receiving LEP-(136–150), LEP-(146–160), or LEP-(156–167), was reduced by 15%. The results of this study indicate 1) that leptin activity is localized, at least in part, in domains between residues 106–140; 2) that leptin-related peptides have in vivo effects similar to those of native leptin; and 3) offer hope for development of peptide analogs of leptin having potential application in human or veterinary medicine.

scholarly journals Age-dependent emergence of neurophysiological and behavioral abnormalities in progranulin-deficient mice

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Dávid Nagy ◽  
Lauren Herl Martens ◽  
Liza Leventhal ◽  
Angela Chen ◽  
Craig Kelley ◽  
...  
Keyword(s):  
Frontotemporal Dementia ◽  
Neurodegenerative Disorder ◽  
Neuronal Loss ◽  
Loss Of Function ◽  
Behavioral Alterations ◽  
Response Latencies ◽  
Reward Seeking ◽  
Behavioral Abnormalities ◽  
Age Dependent

Abstract Background Loss-of-function mutations in the progranulin gene cause frontotemporal dementia, a genetic, heterogeneous neurodegenerative disorder. Progranulin deficiency leads to extensive neuronal loss in the frontal and temporal lobes, altered synaptic connectivity, and behavioral alterations. Methods The chronological emergence of neurophysiological and behavioral phenotypes of Grn heterozygous and homozygous mice in the dorsomedial thalamic—medial prefrontal cortical pathway were evaluated by in vivo electrophysiology and reward-seeking/processing behavior, tested between ages 3 and 12.5 months. Results Electrophysiological recordings identified a clear age-dependent deficit in the thalamocortical circuit. Both heterozygous and homozygous mice exhibited impaired input-output relationships and paired-pulse depression, but evoked response latencies were only prolonged in heterozygotes. Furthermore, we demonstrate firstly an abnormal reward-seeking/processing behavior in the homozygous mice which correlates with previously reported neuroinflammation. Conclusion Our findings indicate that murine progranulin deficiency causes age-dependent neurophysiological and behavioral abnormalities thereby indicating their validity in modeling aspects of human frontotemporal dementia.

scholarly journals Attenuation of Nonsense-Mediated mRNA Decay Enhances In Vivo Nonsense Suppression

PLoS ONE ◽  
2013 ◽  
Vol 8 (4) ◽  
pp. e60478 ◽  
Author(s):  
Kim M. Keeling ◽  
Dan Wang ◽  
Yanying Dai ◽  
Srinivasan Murugesan ◽  
Balachandra Chenna ◽  
...  
Keyword(s):  
Mrna Decay ◽  
Nonsense Suppression ◽  
Nonsense Mediated Mrna Decay

scholarly journals Murine cytomegalovirus open reading frame m29.1 augments virus replication both in vitro and in vivo

2007 ◽  
Vol 88 (11) ◽  
pp. 2941-2951 ◽  
Author(s):  
Mohammad M. Ahasan ◽  
Clive Sweet
Keyword(s):  
Virus Replication ◽  
Post Infection ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Open Reading Frame ◽  
Murine Cytomegalovirus ◽  
Reading Frame ◽  
Codon Mutation

Murine cytomegalovirus mutant Rc29, with a premature stop codon mutation in the m29 open reading frame (ORF), produced no apparent phenotype in cell culture or following infection of BALB/c mice. In contrast, a similar mutant virus, Rc29.1, with a premature stop codon mutation in its m29.1 ORF, showed reduced virus yields (2–3 log10 p.f.u. ml−1) in tissue culture. Mutant virus yields in BALB/c mice were delayed, reduced (∼1 log10 p.f.u. per tissue) and persisted less well in salivary glands compared with wild-type (wt) and revertant (Rv29.1) virus. In severe combined immunodeficiency mice, Rc29.1 virus showed delayed and reduced replication initially in all tissues (liver, spleen, kidneys, heart, lung and salivary glands). This delayed death until 31 days post-infection (p.i.) compared with wt (23 days p.i.) but at death virus yields were similar to wt. m29 gene transcription was initiated at early times post-infection, while production of a transcript from ORF m29.1 in the presence of cycloheximide indicated that it was an immediate-early gene. ORFs m29.1 and M28 are expressed from a bicistronic message, which is spliced infrequently. However, it is likely that each ORF expresses its own protein, as antiserum derived in rabbits to the m29.1 protein expressed in bacteria from the m29.1 ORF detected only one protein in Western blot analysis of the size predicted for the m29.1 protein. Our results suggest that neither ORF is essential for virus replication but m29.1 is important for optimal viral growth in vitro and in vivo.

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