scholarly journals Scans of the MYC mRNA reveal multiple stable secondary structures—including a 3′ UTR motif, conserved across vertebrates, that can affect gene expression

2019 ◽  
Author(s):  
Collin A. O’Leary ◽  
Ryan J. Andrews ◽  
Van S. Tompkins ◽  
Jonathan L. Chen ◽  
Jessica L. Childs-Disney ◽  
...  
Keyword(s):  
Internal Ribosomal Entry Site ◽  
Folding Energy ◽  
Entry Site ◽  
Rna Targets ◽  
High Propensity ◽  
Transcriptional Regulatory ◽  
Show Evidence ◽  
Analysis Window ◽  
Affect Gene Expression ◽  
Human Transcription Factor

AbstractThe MYC gene encodes a human transcription factor and proto-oncogene that is dysregulated in over half of all known cancers. To better understand potential post-transcriptional regulatory features affecting MYC expression, we analyzed secondary structure in the MYC mRNA using a program that is optimized for finding small locally-folded motifs with a high propensity for function. This was accomplished by calculating folding metrics across the MYC sequence using a sliding analysis window and generating unique consensus base pairing models weighted by their lower-than-random predicted folding energy. A series of 30 motifs were identified, primarily in the 5’ and 3’ untranslated regions, which show evidence of structural conservation and compensating mutations across vertebrate MYC homologs. This analysis was able to recapitulate known elements found within an internal ribosomal entry site, as well as discover a novel element in the 3’ UTR that is unusually stable and conserved. This novel motif was shown to affect MYC expression: likely via modulation of miRNA target accessibility. In addition to providing basic insights into mechanisms that regulate MYC expression, this study provides numerous, potentially druggable RNA targets for the MYC gene, which is considered “undruggable” at the protein level.

scholarly journals CRISPR-Cas13a mediated targeting of hepatitis C virus internal-ribosomal entry site (IRES) as an effective antiviral strategy

2021 ◽  
Vol 136 ◽  
pp. 111239
Author(s):  
Muhammad Usman Ashraf ◽  
Hafiz Muhammad Salman ◽  
Muhammad Farhan Khalid ◽  
Muhammad Haider Farooq Khan ◽  
Saima Anwar ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Internal Ribosomal Entry Site ◽  
Entry Site ◽  
Ribosomal Entry

scholarly journals Riboproteomics of the Hepatitis C Virus Internal Ribosomal Entry Site

2004 ◽  
Vol 3 (5) ◽  
pp. 949-957 ◽  
Author(s):  
Henry Lu ◽  
Weiqun Li ◽  
William Stafford Noble ◽  
Donald Payan ◽  
D. C. Anderson
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Internal Ribosomal Entry Site ◽  
Entry Site ◽  
Ribosomal Entry

scholarly journals An internal ribosomal entry site mediates redox-sensitive translation of Nrf2

2009 ◽  
Vol 38 (3) ◽  
pp. 778-788 ◽  
Author(s):  
Wenge Li ◽  
Nehal Thakor ◽  
Eugenia Y. Xu ◽  
Ying Huang ◽  
Chi Chen ◽  
...  
Keyword(s):  
Internal Ribosomal Entry Site ◽  
Entry Site ◽  
Ribosomal Entry

scholarly journals Enhanced virus translation enables miR-122-independent Hepatitis C Virus propagation

2021 ◽  
Author(s):  
Mamata Panigrahi ◽  
Michael Palmer ◽  
Joyce A Wilson
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virus Replication ◽  
Rna Structure ◽  
Genome Stability ◽  
Internal Ribosomal Entry Site ◽  
Terminal Region ◽  
Translation Regulation ◽  
Virus Propagation ◽  
Entry Site

The 5’UTR of the Hepatitis C Virus genome forms RNA structures that regulate virus replication and translation. The region contains a viral internal ribosomal entry site and a 5’ terminal region. Binding of the liver specific miRNA, miR-122, to two conserved binding sites in the 5’ terminal region regulates viral replication, translation, and genome stability, and is essential for efficient virus replication, but its precise mechanism of its action is still under debate. A current hypothesis is that miR-122 binding stimulates viral translation by facilitating the viral 5’ UTR to form the translationally active HCV IRES RNA structure. While miR-122 is essential for detectable virus replication in cell culture, several viral variants with 5’ UTR mutations exhibit low level replication in the absence of miR-122. We show that HCV mutants capable of replicating independently of miR-122 also replicate independently of other microRNAs generated by the canonical miRNA synthesis pathway. Further, we also show that the mutant genomes display an enhanced translation phenotype that correlates with their ability to replicate independently of miR-122. Finally, we provide evidence that translation regulation is the major role for miR-122, and show that miR-122-independent HCV replication can be rescued to miR-122-dependent levels by the combined impacts of 5’ UTR mutations that stimulate translation, and by stabilizing the viral genome by knockdown of host exonucleases and phosphatases that degrade the genome. Thus, we provide a model suggesting that translation stimulation and genome stabilization are the primary roles for miR-122 in the virus life cycle.

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 The non-primate hepacivirus 5′ untranslated region possesses internal ribosomal entry site activity

2013 ◽  
Vol 94 (12) ◽  
pp. 2657-2663 ◽  
Author(s):  
Hazel Stewart ◽  
Cheryl Walter ◽  
Dale Jones ◽  
Sinead Lyons ◽  
Peter Simmonds ◽  
...  
Keyword(s):  
Untranslated Region ◽  
Internal Ribosomal Entry Site ◽  
Rna Replication ◽  
Entry Site ◽  
Subgenomic Replicon ◽  
Stem Loop ◽  
Long Range Interactions ◽  
Ribosomal Entry ◽  
Internal Translation ◽  
And Function

The 5′ untranslated region (5′UTR) of the recently described non-primate hepacivirus (NPHV) contains a region with sequence homology to the internal ribosomal entry site (IRES) of hepatitis C virus (HCV) and GB virus B (GBV-B). Here, we demonstrated internal translation initiation by the NPHV 5′UTR in a bicistronic vector. An RNA stem–loop upstream of the NPHV IRES was structurally distinct from corresponding regions in HCV and GBV-B, and was not required for IRES function. Insertion of the NPHV stem–loop into the corresponding region of the HCV 5′UTR within the HCV subgenomic replicon significantly impaired RNA replication, indicating that long-range interactions between the 5′UTR and cis-acting downstream elements within the NPHV genome are not interchangeable with those of HCV. Despite similarities in IRES structure and function between hepaciviruses, replication elements in the NPHV 5′UTR appear functionally distinct from those of HCV.

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