scholarly journals All five cold-shock domains of unr (upstream of N- ras) are required for stimulation of human rhinovirus RNA translation

2004 ◽  
Vol 85 (8) ◽  
pp. 2279-2287 ◽  
Author(s):  
Emma C. Brown ◽  
Richard J. Jackson
Keyword(s):  
Cold Shock ◽  
Rna Binding ◽  
Binding Activity ◽  
Human Rhinovirus ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Rna Translation ◽  
Polypyrimidine Tract Binding Protein ◽  
Stimulation Of

Efficient translation of human rhinovirus-2 (HRV-2) RNA from its internal ribosome entry site (IRES) depends on the presence of cellular trans-acting factors upstream of N- ras (unr) and polypyrimidine-tract-binding protein. unr contains five cold-shock domains (CSDs) and is predicted to act as an RNA chaperone, allowing the HRV-2 IRES to attain the correct conformation for ribosome binding. To investigate the role of each of the CSDs in IRES-dependent translation, five unr mutants, each harbouring a point mutation in a different CSD, were generated. All five mutants were severely impaired in their ability to bind to the IRES and to stimulate translation from it. This showed that the ability of unr to function as an activator of HRV-2 RNA translation requires the RNA-binding activity of all five CSDs.

scholarly journals Internal initiation of translation from the human rhinovirus-2 internal ribosome entry site requires the binding of Unr to two distinct sites on the 5′ untranslated region

2007 ◽  
Vol 88 (11) ◽  
pp. 3043-3052 ◽  
Author(s):  
Emma C. Anderson ◽  
Sarah L. Hunt ◽  
Richard J. Jackson
Keyword(s):  
Internal Ribosome Entry Site ◽  
Binding Sites ◽  
Cold Shock ◽  
Human Rhinovirus ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Polypyrimidine Tract Binding Protein ◽  
Initiation Of Translation ◽  
Cold Shock Domain ◽  
Internal Initiation

Internal initiation of translation from the human rhinovirus-2 (HRV-2) internal ribosome entry site (IRES) is dependent upon host cell trans-acting factors. The multiple cold shock domain protein Unr and the polypyrimidine tract-binding protein have been identified as synergistic activators of HRV-2 IRES-driven translation. In order to investigate the mechanism by which Unr acts in this process, we have mapped the binding sites of Unr to two distinct secondary structure domains of the HRV-2 IRES, and have identified specific nucleotides that are involved in the binding of Unr to the IRES. The data suggest that Unr acts as an RNA chaperone to maintain a complex tertiary IRES structure required for translational competency.

scholarly journals Differential Effects on the Hepatitis C Virus (HCV) Internal Ribosome Entry Site by Vitamin B12 and the HCV Core Protein

2004 ◽  
Vol 78 (21) ◽  
pp. 12075-12081 ◽  
Author(s):  
Dongsheng Li ◽  
William B. Lott ◽  
John Martyn ◽  
Gholamreza Haqshenas ◽  
Eric J. Gowans
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Internal Ribosome Entry Site ◽  
Core Protein ◽  
Vitamin B ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Hcv Core Protein ◽  
Hcv Ires

ABSTRACT To investigate the role of the hepatitis C virus internal ribosome entry site (HCV IRES) domain IV in translation initiation and regulation, two chimeric IRES elements were constructed to contain the reciprocal domain IV in the otherwise HCV and classical swine fever virus IRES elements. This permitted an examination of the role of domain IV in the control of HCV translation. A specific inhibitor of the HCV IRES, vitamin B12, was shown to inhibit translation directed by all IRES elements which contained domain IV from the HCV and the GB virus B IRES elements, whereas the HCV core protein could only suppress translation from the wild-type HCV IRES. Thus, the mechanisms of translation inhibition by vitamin B12 and the core protein differ, and they target different regions of the IRES.

scholarly journals An inducible cytoplasmic factor (AU-B) binds selectively to AUUUA multimers in the 3' untranslated region of lymphokine mRNA.

1991 ◽  
Vol 11 (6) ◽  
pp. 3288-3295 ◽  
Author(s):  
P R Bohjanen ◽  
B Petryniak ◽  
C H June ◽  
C B Thompson ◽  
T Lindsten
Keyword(s):  
Untranslated Region ◽  
Rna Binding ◽  
Cell Receptor ◽  
Binding Activity ◽  
Myristate Acetate ◽  
Cytoplasmic Factor ◽  
Mrna Metabolism ◽  
Rna And Protein Synthesis ◽  
Quiescent T Cells ◽  
Stimulation Of

Considerable evidence suggests that the metabolism of lymphokine mRNAs can be selectively regulated within the cytoplasm. However, little is known about the mechanism(s) that cells use to discriminate lymphokine mRNAs from other mRNAs within the cytoplasm. In this study we report a sequence-specific cytoplasmic factor (AU-B) that binds specifically to AUUUA multimers present in the 3' untranslated region of lymphokine mRNAs. AU-B does not bind to monomeric AUUUA motifs nor to other AU-rich sequences present in the 3' untranslated region of c-myc mRNA. AU-B RNA-binding activity is not present in quiescent T cells but is rapidly induced by stimulation of the T-cell receptor/CD3 complex. Induction of AU-B RNA-binding activity requires new RNA and protein synthesis. Stabilization of lymphokine mRNA induced by costimulation with phorbol myristate acetate correlates inversely with binding by AU-B. Together, these data suggest that AU-B is a cytoplasmic regulator of lymphokine mRNA metabolism.

scholarly journals Role of RNA-Binding Activity of Hu in Chromosomal Organization

2019 ◽  
Vol 116 (3) ◽  
pp. 469a
Author(s):  
Kelsey E. Bettridge ◽  
Xiaoli Weng ◽  
Subhash Verma ◽  
Sankar Adhya ◽  
Jie Xiao
Keyword(s):  
Rna Binding ◽  
Binding Activity ◽  
Chromosomal Organization

scholarly journals Efficient Translation Initiation Directed by the 900-Nucleotide-Long and GC-Rich 5′ Untranslated Region of the Human Retrotransposon LINE-1 mRNA Is Strictly Cap Dependent Rather than Internal Ribosome Entry Site Mediated

2007 ◽  
Vol 27 (13) ◽  
pp. 4685-4697 ◽  
Author(s):  
Sergey E. Dmitriev ◽  
Dmitri E. Andreev ◽  
Ilya M. Terenin ◽  
Ivan A. Olovnikov ◽  
Vladimir S. Prassolov ◽  
...  
Keyword(s):  
Translation Initiation ◽  
Internal Ribosome Entry Site ◽  
Untranslated Region ◽  
High Efficiency ◽  
Rna Binding ◽  
Cultured Cells ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Cellular Mrnas ◽  
Internal Initiation

ABSTRACT Retrotransposon L1 is a mobile genetic element of the LINE family that is extremely widespread in the mammalian genome. It encodes a dicistronic mRNA, which is exceptionally rare among eukaryotic cellular mRNAs. The extremely long and GC-rich L1 5′ untranslated region (5′UTR) directs synthesis of numerous copies of RNA-binding protein ORF1p per mRNA. One could suggest that the 5′UTR of L1 mRNA contained a powerful internal ribosome entry site (IRES) element. Using transfection of cultured cells with the polyadenylated monocistronic (L1 5′UTR-Fluc) or bicistronic (Rluc-L1 5′UTR-Fluc) RNA constructs, capped or uncapped, it has been firmly established that the 5′UTR of L1 does not contain an IRES. Uncapping reduces the initiation activity of the L1 5′UTR to that of background. Moreover, the translation is inhibited by upstream AUG codons in the 5′UTR. Nevertheless, this cap-dependent initiation activity of the L1 5′UTR was unexpectedly high and resembles that of the beta-actin 5′UTR (84 nucleotides long). Strikingly, the deletion of up to 80% of the nucleotide sequence of the L1 5′UTR, with most of its stem loops, does not significantly change its translation initiation efficiency. These data can modify current ideas on mechanisms used by 40S ribosomal subunits to cope with complex 5′UTRs and call into question the conception that every long GC-rich 5′UTR working with a high efficiency has to contain an IRES. Our data also demonstrate that the ORF2 translation initiation is not directed by internal initiation, either. It is very inefficient and presumably based on a reinitiation event.

scholarly journals The hnRNA-Binding Proteins hnRNP L and PTB Are Required for Efficient Translation of the Cat-1 Arginine/Lysine Transporter mRNA during Amino Acid Starvation

2009 ◽  
Vol 29 (10) ◽  
pp. 2899-2912 ◽  
Author(s):  
Mithu Majumder ◽  
Ibrahim Yaman ◽  
Francesca Gaccioli ◽  
Vladimir V. Zeenko ◽  
Chuanping Wang ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Binding Protein ◽  
Mrna Translation ◽  
Amino Acid Starvation ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Polypyrimidine Tract Binding Protein ◽  
Global Protein Synthesis

ABSTRACT The response to amino acid starvation involves the global decrease of protein synthesis and an increase in the translation of some mRNAs that contain an internal ribosome entry site (IRES). It was previously shown that translation of the mRNA for the arginine/lysine amino acid transporter Cat-1 increases during amino acid starvation via a mechanism that utilizes an IRES in the 5′ untranslated region of the Cat-1 mRNA. It is shown here that polypyrimidine tract binding protein (PTB) and an hnRNA binding protein, heterogeneous nuclear ribonucleoprotein L (hnRNP L), promote the efficient translation of Cat-1 mRNA during amino acid starvation. Association of both proteins with Cat-1 mRNA increased during starvation with kinetics that paralleled that of IRES activation, although the levels and subcellular distribution of the proteins were unchanged. The sequence CUUUCU within the Cat-1 IRES was important for PTB binding and for the induction of translation during amino acid starvation. Binding of hnRNP L to the IRES or the Cat-1 mRNA in vivo was independent of PTB binding but was not sufficient to increase IRES activity or Cat-1 mRNA translation during amino acid starvation. In contrast, binding of PTB to the Cat-1 mRNA in vivo required hnRNP L. A wider role of hnRNP L in mRNA translation was suggested by the decrease of global protein synthesis in cells with reduced hnRNP L levels. It is proposed that PTB and hnRNP L are positive regulators of Cat-1 mRNA translation via the IRES under stress conditions that cause a global decrease of protein synthesis.

scholarly journals RNA-binding Protein HuR Interacts with Thrombomodulin 5′Untranslated Region and Represses Internal Ribosome Entry Site–mediated Translation under IL-1β Treatment

2008 ◽  
Vol 19 (9) ◽  
pp. 3812-3822 ◽  
Author(s):  
Chiu-Hung Yeh ◽  
Liang-Yi Hung ◽  
Chin Hsu ◽  
Shu-Yun Le ◽  
Pin-Tse Lee ◽  
...  
Keyword(s):  
Protein Expression ◽  
Internal Ribosome Entry Site ◽  
Untranslated Region ◽  
Protein C ◽  
Rna Binding ◽  
Activated Protein C ◽  
Critical Factor ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Sepsis And Septic Shock

Reduction in host-activated protein C levels and resultant microvascular thrombosis highlight the important functional role of protein C anticoagulant system in the pathogenesis of sepsis and septic shock. Thrombomodulin (TM) is a critical factor to activate protein C in mediating the anticoagulation and anti-inflammation effects. However, TM protein content is decreased in inflammation and sepsis, and the mechanism is still not well defined. In this report, we identified that the TM 5′ untranslated region (UTR) bearing the internal ribosome entry site (IRES) element controls TM protein expression. Using RNA probe pulldown assay, HuR was demonstrated to interact with the TM 5′UTR. Overexpression of HuR protein inhibited the activity of TM IRES, whereas on the other hand, reducing the HuR protein level reversed this effect. When cells were treated with IL-1β, the IRES activity was suppressed and accompanied by an increased interaction between HuR and TM 5′UTR. In the animal model of sepsis, we found the TM protein expression level to be decreased while concurrently observing the increased interaction between HuR and TM mRNA in liver tissue. In summary, HuR plays an important role in suppression of TM protein synthesis in IL-1β treatment and sepsis.

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