scholarly journals Synergistic Activation of Defense Responses in Arabidopsis by Simultaneous Loss of the GSL5 Callose Synthase and the EDR1 Protein Kinase

2010 ◽  
Vol 23 (5) ◽  
pp. 578-584 ◽  
Author(s):  
Anna Wawrzynska ◽  
Natalie L. Rodibaugh ◽  
Roger W. Innes
Keyword(s):  
Powdery Mildew ◽  
Positional Cloning ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Defense Responses ◽  
Loss Of Function ◽  
Callose Synthase ◽  
Synergistic Activation ◽  
Golovinomyces Cichoracearum ◽  
Inducible Gene

Loss-of-function mutations in the EDR1 gene of Arabidopsis confer enhanced resistance to Golovinomyces cichoracearum (powdery mildew). Disease resistance mediated by the edr1 mutation is dependent on an intact salicylic acid (SA) signaling pathway, but edr1 mutant plants do not constitutively express the SA-inducible gene PR-1 and are not dwarfed. To identify other components of the EDR1 signaling network, we screened for mutations that enhanced the edr1 mutant phenotype. Here, we describe an enhancer of edr1 mutant, eed3, which forms spontaneous lesions in the absence of pathogen infection, constitutively expresses both SA- and methyl jasmonate (JA)–inducible defense genes, and is dwarfed. Positional cloning of eed3 revealed that the mutation causes a premature stop codon in GLUCAN SYNTHASE-LIKE 5 (GSL5, also known as POWDERY MILDEW RESISTANT 4), which encodes a callose synthase required for pathogen-induced callose production. Significantly, gsl5 single mutants do not constitutively express PR-1 or AtERF1 (a JA-inducible gene) and are not dwarfed. Thus, loss of both EDR1 and GSL5 function has a synergistic effect. Our data suggest that EDR1 and GSL5 negatively regulate SA and JA production or signaling by independent mechanisms and that negative regulation of defense signaling by GSL5 may be independent of callose production.

scholarly journals Cis-Segregation of c.1171C>T Stop Codon (p.R391*) in SERPINC1 Gene and c.1691G>A Transition (p.R506Q) in F5 Gene and Selected GWAS Multilocus Approach in Inherited Thrombophilia

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 934
Author(s):  
Donato Gemmati ◽  
Giovanna Longo ◽  
Eugenia Franchini ◽  
Juliana Araujo Silva ◽  
Ines Gallo ◽  
...  
Keyword(s):  
At Risk ◽  
Stop Codon ◽  
Association Studies ◽  
Premature Stop Codon ◽  
Large Family ◽  
Genome Wide Association Studies ◽  
Loss Of Function ◽  
Gene Markers ◽  
Inherited Thrombophilia ◽  
Fv Leiden

Inherited thrombophilia (e.g., venous thromboembolism, VTE) is due to rare loss-of-function mutations in anticoagulant factors genes (i.e., SERPINC1, PROC, PROS1), common gain-of-function mutations in procoagulant factors genes (i.e., F5, F2), and acquired risk conditions. Genome Wide Association Studies (GWAS) recently recognized several genes associated with VTE though gene defects may unpredictably remain asymptomatic, so calculating the individual genetic predisposition is a challenging task. We investigated a large family with severe, recurrent, early-onset VTE in which two sisters experienced VTE during pregnancies characterized by a perinatal in-utero thrombosis in the newborn and a life-saving pregnancy-interruption because of massive VTE, respectively. A nonsense mutation (CGA > TGA) generating a premature stop-codon (c.1171C>T; p.R391*) in the exon 6 of SERPINC1 gene (1q25.1) causing Antithrombin (AT) deficiency and the common missense mutation (c.1691G>A; p.R506Q) in the exon 10 of F5 gene (1q24.2) (i.e., FV Leiden; rs6025) were coinherited in all the symptomatic members investigated suspecting a cis-segregation further confirmed by STR-linkage-analyses [i.e., SERPINC1 IVS5 (ATT)5–18, F5 IVS2 (AT)6–33 and F5 IVS11 (GT)12–16] and SERPINC1 intragenic variants (i.e., rs5878 and rs677). A multilocus investigation of blood-coagulation balance genes detected the coexistence of FV Leiden (rs6025) in trans with FV HR2-haplotype (p.H1299R; rs1800595) in the aborted fetus, and F11 rs2289252, F12 rs1801020, F13A1 rs5985, and KNG1 rs710446 in the newborn and other members. Common selected gene variants may strongly synergize with less common mutations tuning potential life-threatening conditions when combined with rare severest mutations. Merging classic and newly GWAS-identified gene markers in at risk families is mandatory for VTE risk estimation in the clinical practice, avoiding partial risk score evaluation in unrecognized at risk patients.

scholarly journals Loss-of-function in IRF2BPL is associated with neurological phenotypes

2018 ◽  
Author(s):  
Paul C. Marcogliese ◽  
Vandana Shashi ◽  
Rebecca C. Spillmann ◽  
Nicholas Stong ◽  
Jill A. Rosenfeld ◽  
...  
Keyword(s):  
Nervous System ◽  
Population Genomics ◽  
Stop Codon ◽  
Ectopic Expression ◽  
Premature Stop Codon ◽  
Model Organism ◽  
Global Developmental Delay ◽  
Mendelian Disease ◽  
Loss Of Function ◽  
Missense Variants

AbstractThe Interferon Regulatory Factor 2 Binding Protein Like (IRF2BPL) gene encodes a member of the IRF2BP family of transcriptional regulators. Currently the biological function of this gene is obscure, and the gene has not been associated with a Mendelian disease. Here we describe seven individuals affected with neurological symptoms who carry damaging heterozygous variants in IRF2BPL. Five cases carrying nonsense variants in IRF2BPL resulting in a premature stop codon display severe neurodevelopmental regression, hypotonia, progressive ataxia, seizures, and a lack of coordination. Two additional individuals, both with missense variants, display global developmental delay and seizures and a relatively milder phenotype than those with nonsense alleles. The bioinformatics signature for IRF2BPL based on population genomics is consistent with a gene that is intolerant to variation. We show that the IRF2BPL ortholog in the fruit fly, called pits (protein interacting with Ttk69 and Sin3A), is broadly expressed including the nervous system. Complete loss of pits is lethal early in development, whereas partial knock-down with RNA interference in neurons leads to neurodegeneration, revealing requirement for this gene in proper neuronal function and maintenance. The nonsense variants in IRF2BPL identified in patients behave as severe loss-of-function alleles in this model organism, while ectopic expression of the missense variants leads to a range of phenotypes. Taken together, IRF2BPL and pits are required in the nervous system in humans and flies, and their loss leads to a range of neurological phenotypes in both species.

scholarly journals Molecular genetic study in two patients with congenital hypoaldosteronism (types I and II) in relation to previously published hormonal studies

1998 ◽  
pp. 96-100 ◽  
Author(s):  
M Peter ◽  
K Bunger ◽  
SL Drop ◽  
WG Sippell
Keyword(s):  
Genetic Study ◽  
Stop Codon ◽  
Molecular Genetic ◽  
Premature Stop Codon ◽  
Type I ◽  
Type Ii ◽  
Loss Of Function ◽  
Molecular Genetic Study ◽  
Base Exchange ◽  
Deficiency Type

We performed a molecular genetic study in two patients with congenital hypoaldosteronism. An original study of these patients was published in this Journal in 1982. Both index cases, a girl (patient 1) and a boy (patient 2). presented with salt-wasting and failure to thrive in the neonatal period. Parents of patient 1 were not related, whereas the parents of patient 2 were cousins. Endocrine studies had shown a defect in 18-oxidation of 18-OH-corticosterone in patient 1 and a defect in the 18-hydroxylation of corticosterone in patient 2. Plasma aldosterone was decreased in both patients, whereas 18-OH-corticosterone was elevated in patient 1 and decreased in patient 2. Plasma corticosterone and 11-deoxycorticosterone were elevated in both patients, whereas cortisol and its precursors were in the normal range. According to the nomenclature proposed by Ulick, the defects are termed corticosterone methyl oxidase (CMO) deficiency type II in patient 1, and type I in patient 2 respectively. Genetic defects in the gene CYP11B2 encoding aldosterone synthase have been described in a few cases. In patient 1, we identified only one heterozygous amino acid substitution (V386A) in exon 7, which has no deleterious effect on the enzyme activity. In patient 2 and his older brother, we identified a homozygous single base exchange (G to T) in codon 255 (GAG), causing a premature stop codon E255X (TAG). The mutant enzyme has lost the five terminal exons containing the haem binding site, and is thus a loss of function enzyme. This is only the second report of a patient with CMO deficiency type II without a mutation in the exons and exon-intron boundaries, whereas the biochemical phenotype of the two brothers with CMO deficiency type I can be explained by the patient's genotype.

scholarly journals Therapeutic base and prime editing of COL7A1 mutations in recessive dystrophic epidermolysis bullosa

2021 ◽  
Author(s):  
Sung-ah Hong ◽  
Song-Ee Kim ◽  
A-young Lee ◽  
Gue-ho Hwang ◽  
Jong Hoon Kim ◽  
...  
Keyword(s):  
Epidermolysis Bullosa ◽  
Ex Vivo ◽  
Stop Codon ◽  
Point Mutations ◽  
Premature Stop Codon ◽  
Loss Of Function ◽  
Dystrophic Epidermolysis Bullosa ◽  
Immunodeficient Mice ◽  
Type Vii Collagen ◽  
Recessive Dystrophic Epidermolysis Bullosa

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe skin fragility disorder caused by loss-of-function mutations in the COL7A1 gene, which encodes type VII collagen (C7), a protein that functions in skin adherence. From 36 Korean RDEB patients, we identified a total of 69 pathogenic mutations (40 variants without recurrence), including point mutations (72.5%) and insertion/deletion mutations (27.5%). We used base and prime editing to correct mutations in fibroblasts from two patients (Pat1, who carried a c.3631C>T mutation in one allele, and Pat2, who carried a c.2005C>T mutation in one allele). We applied adenine base editors (ABEs) to correct the pathogenic mutation or to bypass a premature stop codon in Pat1-derived primary fibroblasts. To expand the targeting scope, we also utilized prime editors (PEs) to correct the mutations in Pat1- and Pat2-derived fibroblasts. Ultimately, we found that both ABE- and PE-mediated correction of COL7A1 mutations restored full-length C7 expression, reversed the impaired adhesion and proliferation exhibited by the patient-derived fibroblasts, and, following transfer of edited patient-derived fibroblasts into the skin of immunodeficient mice, led to C7 deposition within the dermal-epidermal junction. These results suggest that base and prime editing could be feasible strategies for ex vivo gene editing to treat RDEB.

scholarly journals Molecular structure of soybean E-genes and their functional mutations

2020 ◽  
pp. 3-13
Author(s):  
O. Okhrymovych ◽  
◽  
S. Chebotar ◽  
G. Chebotar ◽  
D. Zharikova ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Genetic Network ◽  
Structural Features ◽  
Loss Of Function ◽  
Nucleotide Substitutions ◽  
Early Maturity ◽  
E Gene ◽  
Wide Range

In this review, we discuss features of the molecular structure of known E-loci (early maturity) and their involvement in signaling to plant flowering, depending on the sensitivity of soybean genotypes to the photoperiod. These loci contribute to the adaptation of plants to a wide range of natural conditions due to mutations in genes and QTL that control flowering time. At the molecular level, E-genes are significantly different in structural features, origin and function. The lenghth of the identified genes range from one exon to 525 bp encoding the transcription factor (E1), up to 14 exons and about 20 kb for the GmGIa gene (E2). Among the functional mutations that in most cases lead to partial or complete loss of function, there are single-nucleotide substitutions or deletions, insertions of transposon-like sequences that can lead to amino acid substitutions in the protein, shift of the reading frame, appearance of the premature stop-codon. E-gene products are receptors of signals coming from the environment and they participate in signaling pathways that control the photoperiod. The overall impact and interactions between E-genes have not been fully studied yet, the molecular structure was investigated only for E1-E4, for which a genetic network of interactions was proposed, while at the same time five loci (E6-E9 and E11) were only mapped on soybean chromosomes, and the existence of a separate E5 locus has not yet been established. In eight of the 11 E-loci, the dominant allele causes late flowering. Also there is a pleiotropic effect of E-gene alleles on yield, plant height, stress resistance, and response to low temperatures. Knowledge of the allelic state of only some of the 11 genes is not sufficient. A comprehensive understanding of the functioning of the photoperiodic genetic response network is needed. E-genes are genetic determinants that can be used during selection and creation of new varieties with programmed rates of development.

scholarly journals Arabidopsis EDR1 Protein Kinase Regulates the Association of EDS1 and PAD4 to Inhibit Cell Death

2020 ◽  
Vol 33 (4) ◽  
pp. 693-703 ◽  
Author(s):  
Matthew Neubauer ◽  
Irene Serrano ◽  
Natalie Rodibaugh ◽  
Deepak D. Bhandari ◽  
Jaqueline Bautor ◽  
...  
Keyword(s):  
Cell Death ◽  
Protein Kinase ◽  
Defense Responses ◽  
Loss Of Function ◽  
Wild Type ◽  
Independent Function ◽  
Signaling Function ◽  
Golovinomyces Cichoracearum ◽  
Powdery Mildew Pathogen ◽  
Heteromeric Association

ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1) and PHYTOALEXIN DEFICIENT4 (PAD4) are sequence-related lipase-like proteins that function as a complex to regulate defense responses in Arabidopsis by both salicylic acid–dependent and independent pathways. Here, we describe a gain-of-function mutation in PAD4 (S135F) that enhances resistance and cell death in response to infection by the powdery mildew pathogen Golovinomyces cichoracearum. The mutant PAD4 protein accumulates to wild-type levels in Arabidopsis cells, thus these phenotypes are unlikely to be due to PAD4 over accumulation. The phenotypes are similar to loss-of-function mutations in the protein kinase EDR1 (Enhanced Disease Resistance1), and previous work has shown that loss of PAD4 or EDS1 suppresses edr1-mediated phenotypes, placing these proteins downstream of EDR1. Here, we show that EDR1 directly associates with EDS1 and PAD4 and inhibits their interaction in yeast and plant cells. We propose a model whereby EDR1 negatively regulates defense responses by interfering with the heteromeric association of EDS1 and PAD4. Our data indicate that the S135F mutation likely alters an EDS1-independent function of PAD4, potentially shedding light on a yet-unknown PAD4 signaling function.

scholarly journals Lack of FAM20A, Ectopic Gingival Mineralization and Chondro/Osteogenic Modifications in Enamel Renal Syndrome

2020 ◽  
Vol 8 ◽  
Author(s):  
Victor Simancas Escorcia ◽  
Abdoulaziz Diarra ◽  
Adrien Naveau ◽  
Arnaud Dessombz ◽  
Rufino Felizardo ◽  
...  
Keyword(s):  
Stop Codon ◽  
Sequence Similarity ◽  
Premature Stop Codon ◽  
Matrix Composition ◽  
Gingival Tissue ◽  
Thoracic Vertebrae ◽  
Gingival Fibroblasts ◽  
Loss Of Function ◽  
Fiber Network ◽  
Gingival Overgrowth

Enamel renal syndrome (ERS) is a rare recessive disorder caused by loss-of-function mutations in FAM20A (family with sequence similarity 20 member A, OMIM #611062). Enamel renal syndrome is characterized by amelogenesis imperfecta, delayed or failed tooth eruption, intrapulpal calcifications, gingival overgrowth and nephrocalcinosis. Although gingival overgrowth has consistently been associated with heterotopic calcifications the pathogenesis, structure and interactions of the mineral deposits with the surrounding connective tissue are largely unknown. We here report a novel FAM20A mutation in exon 1 (c.358C > T) introducing a premature stop codon (p.Gln120*) and resulting in a complete loss of FAM20A. In addition to the typical oral findings and nephrocalcinosis, ectopic calcified nodules were also seen in the cervical and thoracic vertebrae regions. Histopathologic analysis of the gingiva showed an enlarged papillary layer associated with aberrant angiogenesis and a lamina propria displaying significant changes in its extracellular matrix composition, including disruption of the collagen I fiber network. Ectopic calcifications were found throughout the connective gingival tissue. Immunomorphological and ultrastructural analyses indicated that the calcification process was associated with epithelial degeneration and transformation of the gingival fibroblasts to chondro/osteoblastic-like cells. Mutant gingival fibroblasts cultures were prone to calcify and abnormally expressed osteoblastic markers such as RUNX2 or PERIOSTIN. Our findings expand the previously reported phenotypes and highlight some aspects of ERS pathogenesis.

scholarly journals Early onset combined immunodeficiency and autoimmunity in patients with loss-of-function mutation in LAT

2016 ◽  
Vol 213 (7) ◽  
pp. 1185-1199 ◽  
Author(s):  
Baerbel Keller ◽  
Irina Zaidman ◽  
O. Sascha Yousefi ◽  
Dov Hershkovitz ◽  
Jerry Stein ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Autoimmune Disease ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Signal Propagation ◽  
Homozygous Mutation ◽  
Combined Immunodeficiency ◽  
Loss Of Function ◽  
Extracellular Signal

The adapter protein linker for activation of T cells (LAT) is a critical signaling hub connecting T cell antigen receptor triggering to downstream T cell responses. In this study, we describe the first kindred with defective LAT signaling caused by a homozygous mutation in exon 5, leading to a premature stop codon deleting most of the cytoplasmic tail of LAT, including the critical tyrosine residues for signal propagation. The three patients presented from early childhood with combined immunodeficiency and severe autoimmune disease. Unlike in the mouse counterpart, reduced numbers of T cells were present in the patients. Despite the reported nonredundant role of LAT in Ca2+ mobilization, residual T cells were able to induce Ca2+ influx and nuclear factor (NF) κB signaling, whereas extracellular signal-regulated kinase (ERK) signaling was completely abolished. This is the first report of a LAT-related disease in humans, manifesting by a progressive combined immune deficiency with severe autoimmune disease.

scholarly journals Spontaneous Loss of Virulence in Natural Populations of Listeria monocytogenes

2017 ◽  
Vol 85 (11) ◽  
Author(s):  
Mylène M. Maury ◽  
Viviane Chenal-Francisque ◽  
Hélène Bracq-Dieye ◽  
Lei Han ◽  
Alexandre Leclercq ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Host Cells ◽  
Single Amino Acid ◽  
Listeriolysin O ◽  
Loss Of Function ◽  
Phenotypic Marker ◽  
Content Type ◽  
Virulence Attenuation

ABSTRACT The pathogenesis of Listeria monocytogenes depends on the ability of this bacterium to escape from the phagosome of the host cells via the action of the pore-forming toxin listeriolysin O (LLO). Expression of the LLO-encoding gene (hly) requires the transcriptional activator PrfA, and both hly and prfA genes are essential for L. monocytogenes virulence. Here, we used the hemolytic activity of LLO as a phenotypic marker to screen for spontaneous virulence-attenuating mutations in L. monocytogenes. Sixty nonhemolytic isolates were identified among a collection of 57,820 confirmed L. monocytogenes strains isolated from a variety of sources (0.1%). In most cases (56/60; 93.3%), the nonhemolytic phenotype resulted from nonsense, missense, or frameshift mutations in prfA. Five strains carried hly mutations leading to a single amino acid substitution (G299V) or a premature stop codon causing strong virulence attenuation in mice. In one strain, both hly and gshF (encoding a glutathione synthase required for full PrfA activity) were missing due to genomic rearrangements likely caused by a transposable element. The PrfA/LLO loss-of-function (PrfA−/LLO−) mutants belonged to phylogenetically diverse clades of L. monocytogenes, and most were identified among nonclinical strains (57/60). Consistent with the rare occurrence of loss-of-virulence mutations, we show that prfA and hly are under purifying selection. Although occurring at a low frequency, PrfA−/LLO− mutational events in L. monocytogenes lead to niche restriction and open an evolutionary path for obligate saprophytism in this facultative intracellular pathogen.

Loss of cysteine 584 impairs the storage and release, but not the synthesis of von Willebrand factor

2014 ◽  
Vol 112 (12) ◽  
pp. 1159-1166 ◽  
Author(s):  
Viviana Daidone ◽  
Giovanni Barbon ◽  
Elena Pontara ◽  
Grazia Cattini ◽  
Lisa Gallinaro ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Von Willebrand Disease ◽  
Hek293 Cells ◽  
Loss Of Function ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryCysteines play a key part in von Willebrand factor (VWF) dimerisation and polymerisation, and their loss may severely affect VWF structure and function. We report on three patients with type 3 von Willebrand disease carrying the new c.1751G>T missense mutation that induces the substitution of cysteine 584 by phenylalanine (C584F), and the deletion of seven nucleotides in exon 7 (c.729_735del), producing a premature stop codon at position 454 (E244Lfs*211). VWF was almost undetectable in the patients’ plasma and platelets, while a single, poorly represented, oligomer emerged on plasma VWF multimer analysis. No post-DDAVP increase in VWF and factor VIII was observed. Expressing human recombinant C584F-VWF in HEK293T cells showed that C584F-VWF was synthesised and multimerised but not secreted – apart from the first oligomer, which was slightly represented in the conditioned medium, with a pattern similar to the patients’ plasma VWF. The in vitro expression of the E244Lfs*211–VWF revealed a defective synthesis of the mutated VWF, with a behavior typical of loss of function mutations. Cellular trafficking, investigated in HEK293 cells, indicated a normal C584F-VWF content in the endoplasmic reticulum and Golgi apparatus, confirming the synthesis and multimerisation of C584F-VWF. No pseudo-Weibel Palade bodies were demonstrable, however, suggesting that C584F mutation impairs the storage of C584F-VWF. These findings point to cysteine 584 having a role in the release of VWF and its targeting to pseudo-Weibel Palade bodies in vitro, as well as in its storage and release by endothelial cells in vivo.

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