scholarly journals The Absence of Eukaryotic Initiation Factor eIF(iso)4E Affects the Systemic Spread of a Tobacco etch virus Isolate in Arabidopsis thaliana

2013 ◽  
Vol 26 (4) ◽  
pp. 461-470 ◽  
Author(s):  
Carlos A. Contreras-Paredes ◽  
Laura Silva-Rosales ◽  
José-Antonio Daròs ◽  
Naholi D. Alejandri-Ramírez ◽  
Tzvetanka D. Dinkova
Keyword(s):  
Arabidopsis Thaliana ◽  
Mosaic Virus ◽  
Resistance Mechanism ◽  
Tobacco Etch Virus ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Viral Translation ◽  
Systemic Spread ◽  
Viral Coat

Translation initiation factor eIF4E exerts an important role during infection of viral species in the family Potyviridae. Particularly, a eIF(iso)4E family member is required for Arabidopsis thaliana susceptibility to Turnip mosaic virus, Lettuce mosaic virus, and Tobacco etch virus (TEV). In addition, a resistance mechanism named restriction of TEV movement (RTM) in A. thaliana controls the systemic spread of TEV in Col-0 ecotype. Here, we describe that TEV-TAMPS, a Mexican isolate, overcomes the RTM resistance mechanism reported for TEV-7DA infection of the Col-0 ecotype but depends on eIF(iso)4E for its systemic spread. To understand at which level eIF(iso)4E participates in A. thaliana TEV-TAMPS infection, the viral RNA replication and translation were measured. The absence or overexpression of eIF(iso)4E did not affect viral translation, and replication was still observed in the absence of eIF(iso)4E. However, the TEV-TAMPS systemic spread was completely abolished in the null mutant. The viral protein genome-linked (VPg) precursor NIa was found in coimmunoprecipitated complexes with both, eIF(iso)4E and eIF4E. However, the viral coat protein (CP) was only present in the eIF(iso)4E complexes. Since both the VPg and the CP proteins are needed for systemic spread, we propose a role of A. thaliana eIF(iso)4E in the movement of TEV-TAMPS within this host.

scholarly journals Recessive Resistance to Bean common mosaic virus Conferred by the bc-1 and bc-2 Genes in Common Bean (Phaseolus vulgaris) Affects Long-Distance Movement of the Virus

2018 ◽  
Vol 108 (8) ◽  
pp. 1011-1018 ◽  
Author(s):  
Xue Feng ◽  
Gardenia E. Orellana ◽  
James R. Myers ◽  
Alexander V. Karasev
Keyword(s):  
Phaseolus Vulgaris ◽  
Common Bean ◽  
Mosaic Virus ◽  
Bean Common Mosaic Virus ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Recessive Resistance ◽  
Long Distance ◽  
Systemic Spread ◽  
Long Distance Movement

Recessive resistance to Bean common mosaic virus (BCMV) in common bean (Phaseolus vulgaris) is governed by four genes that include one strain-nonspecific helper gene bc-u, and three strain-specific genes bc-1, bc-2, and bc-3. The bc-3 gene was identified as an eIF4E translation initiation factor gene mediating resistance through disruption of the interaction between this protein and the VPg protein of the virus. The mode of action of bc-1 and bc-2 in expression of BCMV resistance is unknown, although bc-1 gene was found to affect systemic spread of a related potyvirus, Bean common mosaic necrosis virus. To investigate the possible role of both bc-1 and bc-2 genes in replication, cell-to-cell, and long-distance movement of BCMV in P. vulgaris, we tested virus spread of eight BCMV isolates representing pathogroups I, IV, VI, VII, and VIII in a set of bean differentials expressing different combinations of six resistance alleles including bc-u, bc-1, bc-12, bc-2, bc-22, and bc-3. All studied BCMV isolates were able to replicate and spread in inoculated leaves of bean cultivars harboring bc-u, bc-1, bc-12, bc-2, and bc-22 alleles and their combinations, while no BCMV replication was found in inoculated leaves of cultivar IVT7214 carrying the bc-u, bc-2, and bc-3 genes, except for isolate 1755a, which was capable of overcoming the resistance conferred by bc-2 and bc-3. In contrast, the systemic spread of all BCMV isolates from pathogroups I, IV, VI, VII, and VIII was impaired in common bean cultivars carrying bc-1, bc-12, bc-2, and bc-22 alleles. The data suggest that bc-1 and bc-2 recessive resistance genes have no effect on the replication and cell-to-cell movement of BCMV, but affect systemic spread of BCMV in common bean. The BCMV resistance conferred by bc-1 and bc-2 and affecting systemic spread was found only partially effective when these two genes were expressed singly. The efficiency of the restriction of the systemic spread of the virus was greatly enhanced when the alleles of bc-1 and bc-2 genes were combined together.

scholarly journals Multiple Resistance Phenotypes to Lettuce mosaic virus Among Arabidopsis thaliana Accessions

2003 ◽  
Vol 16 (7) ◽  
pp. 608-616 ◽  
Author(s):  
Frédéric Revers ◽  
Thomas Guiraud ◽  
Marie-Christine Houvenaghel ◽  
Thierry Mauduit ◽  
Olivier Le Gall ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Mosaic Virus ◽  
Resistance Gene ◽  
Recombinant Inbred Lines ◽  
Cell Movement ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Lettuce Mosaic Virus ◽  
Genetic Analyses ◽  
Large Variability

With the aim to characterize plant and viral factors involved in the molecular interactions between plants and potyviruses, a Lettuce mosaic virus (LMV)-Arabidopsis thaliana pathosystem was developed. Screening of Arabi-dopsis accessions with LMV isolates indicated the existence of a large variability in the outcome of the interaction, allowing the classification of Arabidopsis accessions into seven susceptibility groups. Using a reverse genetic approach, the genome-linked protein of LMV, a multifunc-tional protein shown to be involved in viral genome amplification and movement of potyviruses, was established as the viral determinant responsible for the ability to overcome the resistance of the Niederzenz accession to LMV-0. Preliminary genetic analyses from F2 and recombinant inbred lines available between susceptible and resistant Arabidopsis accessions revealed the existence of at least three resistance phenotypes to LMV with different genetic bases. One dominant resistance gene, designated LLM1, involved in blocking the replication or cell-to-cell movement of the LMV-0 isolate in the Columbia accession, was mapped to chromosome I and shown to be linked to the marker nga280. At the same time, genetic analyses of segregating F2 populations were consistent with the restriction of the systemic movement of the LMV-AF199 isolate in Columbia being controlled by two dominant genes and with the complete resistance to all tested LMV isolates of the Cape Verde islands (Cvi) accession being conferred by a single recessive resistance gene. Sequencing of the eu-karyotic translation initiation factor 4E genes from the different LMV-resistant Arabidopsis accessions showed that these factors are not directly involved in the characterized resistance phenotypes.

Analysis of local and systemic spread of the crucifer-infecting TMV-Cg virus in tobacco and several Arabidopsis thaliana ecotypes

2003 ◽  
Vol 30 (4) ◽  
pp. 401 ◽  
Author(s):  
Patricio Arce-Johnson ◽  
Consuelo Medina ◽  
Hal S. Padgett ◽  
Wilson Huanca ◽  
Carmen Espinoza
Keyword(s):  
Arabidopsis Thaliana ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Movement Protein ◽  
Host Interactions ◽  
Nicotiana Tabacum L ◽  
Systemic Spread ◽  
Movement Protein Gene ◽  
Local Movement

The crucifer-infecting tobacco mosaic virus, TMV-Cg, infects Arabidopsis thaliana (L.) Heynh. efficiently without causing severe symptoms. The systemic spread of TMV-Cg in Arabidopsis was evaluated in 14�ecotypes. Five days after inoculation, TMV-Cg was detected in apical leaves of 8 out of 14 ecotypes. As expected, the spread of TMV-Cg in the ecotypes tested was considerably faster than that of tobacco mosaic virus (TMV-U1). To study the participation of viral proteins in the TMV-Cg-induced infection, a complete genomic cDNA of TMV-Cg was cloned. The role of TMV-Cg movement protein in systemic spread was tested with a hybrid virus, constructed from the TMV-U1 genome and the TMV-Cg movement protein gene. Contrary to expectations, the systemic spread of this hybrid in Arabidopsis was similar to that of TMV-U1. The failure of the hybrid virus to spread at rates similar to those of TMV-Cg was not due to restrictions in local movement. In tobacco (Nicotiana tabacum L.), the hybrid virus spread efficiently and induced systemic mosaic symptoms characteristic of TMV-U1. The TMV-Cg cDNA clone provides an attractive tool to study virus–host interactions.

scholarly journals Arabidopsis thaliana class II poly(A)-binding proteins are required for efficient multiplication of turnip mosaic virus

2008 ◽  
Vol 89 (9) ◽  
pp. 2339-2348 ◽  
Author(s):  
Philippe J. Dufresne ◽  
Eliane Ubalijoro ◽  
Marc G. Fortin ◽  
Jean-François Laliberté
Keyword(s):  
Arabidopsis Thaliana ◽  
Mosaic Virus ◽  
Class Ii ◽  
Turnip Mosaic Virus ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Mrna Levels ◽  
Binding Assays ◽  
Rna Accumulation

The poly(A)-binding protein (PABP) is an important translation initiation factor that binds to the polyadenylated 3′ end of mRNA. We have previously shown that PABP2 interacts with the RNA-dependent RNA polymerase (RdRp) and VPg-Pro of turnip mosaic virus (TuMV) within virus-induced vesicles. At least eight PABP isoforms are produced in Arabidopsis thaliana, three of which (PABP2, PABP4 and PABP8) are highly and broadly expressed and probably constitute the bulk of PABP required for cellular functions. Upon TuMV infection, an increase in protein and mRNA expression from PAB2, PAB4 and PAB8 genes was recorded. In vitro binding assays revealed that RdRp and the viral genome-linked protein (VPg-Pro) interact preferentially with PABP2 but are also capable of interaction with one or both of the other class II PABPs (i.e. PABP4 and PABP8). To assess whether PABP is required for potyvirus replication, A. thaliana single and double pab knockouts were isolated and inoculated with TuMV. All lines showed susceptibility to TuMV. However, when precise monitoring of viral RNA accumulation was performed, it was found to be reduced by 2.2- and 3.5-fold in pab2 pab4 and pab2 pab8 mutants, respectively, when compared with wild-type plants. PABP levels were most significantly reduced in the membrane-associated fraction in both of these mutants. TuMV mRNA levels thus correlated with cellular PABP concentrations in these A. thaliana knockout lines. These data provide further support for a role of PABP in potyvirus replication.

scholarly journals Foot-and-Mouth Disease Virus Viroporin 2B Antagonizes RIG-I-Mediated Antiviral Effects by Inhibition of Its Protein Expression

2016 ◽  
Vol 90 (24) ◽  
pp. 11106-11121 ◽  
Author(s):  
Zixiang Zhu ◽  
Guoqing Wang ◽  
Fan Yang ◽  
Weijun Cao ◽  
Ruoqing Mao ◽  
...  
Keyword(s):  
Protein Expression ◽  
Foot And Mouth Disease ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Eukaryotic Translation ◽  
Mouth Disease Virus ◽  
2B Protein ◽  
Eukaryotic Translation Initiation ◽  
Cellular Apoptosis

ABSTRACTThe role of retinoic acid-inducible gene I (RIG-I) in foot-and-mouth disease virus (FMDV)-infected cells remains unknown. Here, we showed that RIG-I inhibits FMDV replication in host cells. FMDV infection increased the transcription of RIG-I, while it decreased RIG-I protein expression. A detailed analysis revealed that FMDV leader proteinase (Lpro), as well as 3C proteinase (3Cpro) and 2B protein, decreased RIG-I protein expression. Lproand 3Cproare viral proteinases that can cleave various host proteins and are responsible for several of the viral polyprotein cleavages. However, for the first time, we observed 2B-induced reduction of host protein. Further studies showed that 2B-mediated reduction of RIG-I is specific to FMDV, but not other picornaviruses, including encephalomyocarditis virus, enterovirus 71, and coxsackievirus A16. Moreover, we found the decreased protein level of RIG-I is independent of the cleavage of eukaryotic translation initiation factor 4 gamma, the induction of cellular apoptosis, or the association of proteasome, lysosome, and caspase pathways. A direct interaction was observed between RIG-I and 2B. The carboxyl-terminal amino acids 105 to 114 and amino acids 135 to 144 of 2B were essential for the reduction of RIG-I, while residues 105 to 114 were required for the interaction. These data suggest the antiviral role of RIG-I against FMDV and a novel antagonistic mechanism of FMDV that is mediated by 2B protein.IMPORTANCEThis study demonstrated that RIG-I could suppress FMDV replication during virus infection. FMDV infection increased the transcriptional expression of RIG-I, while it decreased RIG-I protein expression. FMDV 2B protein interacted with RIG-I and induced reduction of RIG-I. 2B-induced reduction of RIG-I was independent of the induction of the cleavage of eukaryotic translation initiation factor 4 gamma or cellular apoptosis. In addition, proteasome, lysosome, and caspase pathways were not involved in this process. This study provides new insight into the immune evasion mediated by FMDV and identifies 2B as an antagonistic factor for FMDV to evade the antiviral response.

scholarly journals 4E-BP2–dependent translation in parvalbumin neurons controls epileptic seizure threshold

2021 ◽  
Vol 118 (15) ◽  
pp. e2025522118
Author(s):  
Vijendra Sharma ◽  
Rapita Sood ◽  
Danning Lou ◽  
Tzu-Yu Hung ◽  
Maxime Lévesque ◽  
...  
Keyword(s):  
Animal Models ◽  
Mammalian Target Of Rapamycin ◽  
Neuronal Cell ◽  
Mrna Translation ◽  
Translation Initiation Factor ◽  
Inhibitory Neurons ◽  
Initiation Factor ◽  
Seizure Threshold ◽  
Parvalbumin Neurons

The mechanistic/mammalian target of rapamycin complex 1 (mTORC1) integrates multiple signals to regulate critical cellular processes such as mRNA translation, lipid biogenesis, and autophagy. Germline and somatic mutations in mTOR and genes upstream of mTORC1, such as PTEN, TSC1/2, AKT3, PIK3CA, and components of GATOR1 and KICSTOR complexes, are associated with various epileptic disorders. Increased mTORC1 activity is linked to the pathophysiology of epilepsy in both humans and animal models, and mTORC1 inhibition suppresses epileptogenesis in humans with tuberous sclerosis and animal models with elevated mTORC1 activity. However, the role of mTORC1-dependent translation and the neuronal cell types mediating the effect of enhanced mTORC1 activity in seizures remain unknown. The eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) and 2 (4E-BP2) are translational repressors downstream of mTORC1. Here we show that the ablation of 4E-BP2, but not 4E-BP1, in mice increases the sensitivity to pentylenetetrazole (PTZ)- and kainic acid (KA)–induced seizures. We demonstrate that the deletion of 4E-BP2 in inhibitory, but not excitatory neurons, causes an increase in the susceptibility to PTZ-induced seizures. Moreover, mice lacking 4E-BP2 in parvalbumin, but not somatostatin or VIP inhibitory neurons exhibit a lowered threshold for seizure induction and reduced number of parvalbumin neurons. A mouse model harboring a human PIK3CA mutation that enhances the activity of the PI3K-AKT pathway (Pik3caH1047R-Pvalb) selectively in parvalbumin neurons shows susceptibility to PTZ-induced seizures. Our data identify 4E-BP2 as a regulator of epileptogenesis and highlight the central role of increased mTORC1-dependent translation in parvalbumin neurons in the pathophysiology of epilepsy.

scholarly journals The Potential Role of Protein Kinase R as a Regulator of Age-Related Neurodegeneration

2021 ◽  
Vol 13 ◽  
Author(s):  
Nicolás W. Martinez ◽  
Felipe E. Gómez ◽  
Soledad Matus
Keyword(s):  
Protein Kinase ◽  
Pathological Process ◽  
Translation Initiation Factor ◽  
Initiation Factor ◽  
Protein Kinase R ◽  
Eukaryotic Translation ◽  
Neurodegenerative Process ◽  
Age Related ◽  
Initiation Factor 2

There is a growing evidence describing a decline in adaptive homeostasis in aging-related diseases affecting the central nervous system (CNS), many of which are characterized by the appearance of non-native protein aggregates. One signaling pathway that allows cell adaptation is the integrated stress response (ISR), which senses stress stimuli through four kinases. ISR activation promotes translational arrest through the phosphorylation of the eukaryotic translation initiation factor 2 alpha (eIF2α) and the induction of a gene expression program to restore cellular homeostasis. However, depending on the stimulus, ISR can also induce cell death. One of the ISR sensors is the double-stranded RNA-dependent protein kinase [protein kinase R (PKR)], initially described as a viral infection sensor, and now a growing evidence supports a role for PKR on CNS physiology. PKR has been largely involved in the Alzheimer’s disease (AD) pathological process. Here, we reviewed the antecedents supporting the role of PKR on the efficiency of synaptic transmission and cognition. Then, we review PKR’s contribution to AD and discuss the possible participation of PKR as a player in the neurodegenerative process involved in aging-related pathologies affecting the CNS.

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