scholarly journals Cap-independent translation of encephalomyocarditis virus RNA: structural elements of the internal ribosomal entry site and involvement of a cellular 57-kD RNA-binding protein.

1990 ◽  
Vol 4 (9) ◽  
pp. 1560-1572 ◽  
Author(s):  
S K Jang ◽  
E Wimmer
Keyword(s):  
Rna Binding ◽  
Binding Protein ◽  
Internal Ribosomal Entry Site ◽  
Rna Binding Protein ◽  
Encephalomyocarditis Virus ◽  
Structural Elements ◽  
Entry Site ◽  
Virus Rna ◽  
Ribosomal Entry ◽  
Independent Translation

scholarly journals A Cellular RNA-Binding Protein Enhances Internal Ribosomal Entry Site-Dependent Translation through an Interaction Downstream of the Hepatitis C Virus Polyprotein Initiation Codon

2004 ◽  
Vol 24 (18) ◽  
pp. 7878-7890 ◽  
Author(s):  
Jong Heon Kim ◽  
Ki Young Paek ◽  
Sang Hoon Ha ◽  
Sungchan Cho ◽  
Kobong Choi ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Rna Binding ◽  
Binding Protein ◽  
Internal Ribosomal Entry Site ◽  
Rna Binding Protein ◽  
Mrna Translation ◽  
Entry Site ◽  
Protein Coding ◽  
Ribosomal Entry

ABSTRACT Translational initiation of hepatitis C virus (HCV) mRNA occurs by internal entry of ribosomes into an internal ribosomal entry site (IRES) at the 5′ nontranslated region. A region encoding the N-terminal part of the HCV polyprotein has been shown to augment the translation of HCV mRNA. Here we show that a cellular protein, NS1-associated protein 1 (NSAP1), augments HCV mRNA translation through a specific interaction with an adenosine-rich protein-coding region within the HCV mRNA. The overexpression of NSAP1 specifically enhanced HCV IRES-dependent translation, and knockdown of NSAP1 by use of a small interfering RNA specifically inhibited the translation of HCV mRNA. An HCV replicon RNA capable of mimicking the HCV proliferation process in host cells was further used to confirm that NSAP1 enhances the translation of HCV mRNA. These results suggest the existence of a novel mechanism of translational enhancement that acts through the interaction of an RNA-binding protein with a protein coding sequence.

scholarly journals La protein is required for efficient translation driven by encephalomyocarditis virus internal ribosomal entry site

1999 ◽  
Vol 80 (12) ◽  
pp. 3159-3166 ◽  
Author(s):  
Yoon Ki Kim ◽  
Sung Key Jang
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Protein A ◽  
Internal Ribosomal Entry Site ◽  
Encephalomyocarditis Virus ◽  
Entry Site ◽  
Polypyrimidine Tract Binding Protein ◽  
La Protein ◽  
Ribosomal Entry

Translation of internal ribosomal entry site (IRES)-dependent mRNAs is mediated by RNA-binding proteins as well as canonical translation factors. In order to elucidate the roles of RNA-binding proteins in IRES-dependent translation, the role of polypyrimidine tract-binding protein (PTB) and La protein in encephalomyocarditis virus (EMCV) IRES-dependent translation was investigated. PTB was required for efficient EMCV IRES-driven translation but, intriguingly, an excess of PTB suppressed it. Such a translational suppression by surplus PTB was relieved by addition of La protein. A possible role for La protein in IRES-dependent translation is discussed.

scholarly journals Canonical eukaryotic initiation factors determine initiation of translation by internal ribosomal entry.

1996 ◽  
Vol 16 (12) ◽  
pp. 6859-6869 ◽  
Author(s):  
T V Pestova ◽  
C U Hellen ◽  
I N Shatsky
Keyword(s):  
Internal Ribosomal Entry Site ◽  
Encephalomyocarditis Virus ◽  
Initiation Factor ◽  
Entry Site ◽  
Independent Manner ◽  
Initiation Factors ◽  
Virus Rna ◽  
Initiation Of Translation ◽  
Initiation Factor 2 ◽  
Ribosomal Entry

Translation of picornavirus RNA is initiated after ribosomal binding to an internal ribosomal entry site (IRES) within the 5' untranslated region. We have reconstituted IRES-mediated initiation on encephalomyocarditis virus RNA from purified components and used primer extension analysis to confirm the fidelity of 48S preinitiation complex formation. Eukaryotic initiation factor 2 (eIF2), eIF3, and eIF4F were required for initiation; eIF4B and to a lesser extent the pyrimidine tract-binding protein stimulated this process. We show that eIF4F binds to the IRES in a novel cap-independent manner and suggest that cap- and IRES-dependent initiation mechanisms utilize different modes of interaction with this factor to promote ribosomal attachment to mRNA.

scholarly journals Cell-Type-Specific Repression of Internal Ribosome Entry Site Activity by Double-Stranded RNA-Binding Protein 76

2006 ◽  
Vol 80 (7) ◽  
pp. 3147-3156 ◽  
Author(s):  
Melinda K. Merrill ◽  
Elena Y. Dobrikova ◽  
Matthias Gromeier
Keyword(s):  
Cancer Cells ◽  
Rna Binding ◽  
Binding Protein ◽  
Neuronal Cells ◽  
Rna Binding Protein ◽  
Cell Type ◽  
Entry Site ◽  
Double Stranded Rna ◽  
Cell Type Specific ◽  
Ribosomal Entry

ABSTRACT Translation of picornavirus plus-strand RNA genomes occurs via internal ribosomal entry at highly structured 5′ untranslated regions. In addition to canonical translation factors, translation rate is likely influenced by supplementary host and viral trans-acting factors. We previously reported that insertion of a heterologous human rhinovirus type 2 internal ribosomal entry site (IRES) into the poliovirus (PV) genome, generating the chimeric virus PV-RIPO, selectively abrogates viral translation and propagation in neurons, which eliminate poliovirus's signature neuropathogenicity. While severely deficient in cells of neuronal lineage, the rhinovirus IRES promotes efficient propagation of PV-RIPO in cancer cells. Tumor-specific IRES function can be therapeutically exploited to direct viral cytotoxicity to cancer cells. Neuron-glioma heterokaryon analysis implicates neuronal trans-dominant inhibition in this effect, suggesting that host trans-acting factors repress IRES function in a cell-type-specific manner. We identified a set of proteins from neuronal cells with affinity for the rhinovirus IRES, including double-stranded RNA-binding protein 76 (DRBP76). DRBP76 associates with the IRES in neuronal but not in malignant glioma cells. Moreover, DRBP76 depletion in neuronal cells enhances rhinovirus IRES-driven translation and virus propagation. Our observations suggest that cell-type-specific association of DRBP76 with the rhinovirus IRES represses PV-RIPO translation and propagation in neuronal cells.

scholarly journals Heat Shock Protein A6, a Novel HSP70, Is Induced During Enterovirus A71 Infection to Facilitate Internal Ribosomal Entry Site-Mediated Translation

2021 ◽  
Vol 12 ◽  
Author(s):  
Yu-Siang Su ◽  
Lih-Hwa Hwang ◽  
Chi-Ju Chen
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Neurological Diseases ◽  
Internal Ribosomal Entry Site ◽  
Viral Proteins ◽  
Cellular Protein ◽  
Encephalomyocarditis Virus ◽  
Entry Site ◽  
Enterovirus A71 ◽  
Ribosomal Entry

Enterovirus A71 (EV-A71) is a human pathogen causing hand, foot, and mouth disease (HFMD) in children. Its infection can lead to severe neurological diseases or even death in some cases. While being produced in a large quantity during infection, viral proteins often require the assistance from cellular chaperones for proper folding. In this study, we found that heat shock protein A6 (HSPA6), whose function in viral life cycle is scarcely studied, was induced and functioned as a positive regulator for EV-A71 infection. Depletion of HSPA6 led to the reductions of EV-A71 viral proteins, viral RNA and virions as a result of the downregulation of internal ribosomal entry site (IRES)-mediated translation. Unlike other HSP70 isoforms such as HSPA1, HSPA8, and HSPA9, which regulate all phases of the EV-A71 life, HSPA6 was required for the IRES-mediated translation only. Unexpectedly, the importance of HSPA6 in the IRES activity could be observed in the absence of viral proteins, suggesting that HSPA6 facilitated IRES activity through cellular factor(s) instead of viral proteins. Intriguingly, the knockdown of HSPA6 also caused the reduction of luciferase activity driven by the IRES from coxsackievirus A16, echovirus 9, encephalomyocarditis virus, or hepatitis C virus, supporting that HSPA6 may assist the function of a cellular protein generally required for viral IRES activities.

scholarly journals Identification of calreticulin as a rubella virus RNA binding protein.

1994 ◽  
Vol 91 (26) ◽  
pp. 12770-12774 ◽  
Author(s):  
N. K. Singh ◽  
C. D. Atreya ◽  
H. L. Nakhasi
Keyword(s):  
Rubella Virus ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Virus Rna
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