scholarly journals Nucleotide Variability and Translation Efficiency of the 5′ Untranslated Region of Hepatitis A Virus: Update from Clinical Isolates Associated with Mild and Severe Hepatitis

2010 ◽  
Vol 84 (19) ◽  
pp. 10139-10147 ◽  
Author(s):  
Vincent Mackiewicz ◽  
Anne Cammas ◽  
Delphine Desbois ◽  
Eric Marchadier ◽  
Sandra Pierredon ◽  
...  
Keyword(s):  
Hepatitis A ◽  
Clinical Presentation ◽  
Hepatitis A Virus ◽  
Expression System ◽  
Luciferase Expression ◽  
Translation Efficiency ◽  
Entry Site ◽  
Severe Hepatitis ◽  
Nucleotide Variability

ABSTRACT Mutations in the internal ribosome entry site (IRES) of hepatitis A virus (HAV) have been associated with enhanced in vitro replication and viral attenuation in animal models. To address the possible role of IRES variability in clinical presentation, IRES sequences were obtained from HAV isolates associated with benign (n = 8) or severe (n = 4) hepatitis. IRES activity was assessed using a bicistronic dual-luciferase expression system in adenocarcinoma (HeLa) and hepatoma (HuH7) cell lines. Activity was higher in HuH7 than in HeLa cells, except for an infrequently isolated genotype IIA strain. Though globally low, significant variation in IRES-dependent translation efficiency was observed between field isolates, reflecting the low but significant genetic variability of this region (94.2% ± 0.5% nucleotide identity). No mutation was exclusive of benign or severe hepatitis, and variations in IRES activity were not associated with a clinical phenotype, indirectly supporting the preponderance of host factors in determining the clinical presentation.

scholarly journals Comparative Analysis of Translation Efficiencies of Hepatitis C Virus 5′ Untranslated Regions among Intraindividual Quasispecies Present in Chronic Infection: Opposite Behaviors Depending on Cell Type

2000 ◽  
Vol 74 (22) ◽  
pp. 10827-10833 ◽  
Author(s):  
Julien Laporte ◽  
Isabelle Malet ◽  
Thibault Andrieu ◽  
Vincent Thibault ◽  
Jean-Jacques Toulme ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Expression System ◽  
Luciferase Expression ◽  
Hcv Rna ◽  
Translation Efficiency ◽  
Cell Type ◽  
Entry Site ◽  
Conserved Sequence

ABSTRACT Hepatitis C virus (HCV) RNA translation initiation is dependent on the presence of an internal ribosome entry site (IRES) that is found mostly in its 5′ untranslated region (5′ UTR). While exhibiting the most highly conserved sequence within the genome, the 5′ UTR accumulates small differences, which may be of biological and clinical importance. In this study, using a bicistronic dual luciferase expression system, we have examined the sequence of 5′ UTRs from quasispecies characterized in the serum of a patient chronically infected with HCV genotype 1a and its corresponding translational activity. Sequence heterogeneity between IRES elements led to important changes in their translation efficiency both in vitro and in different cell cultures lines, implying that interactions of RNA with related transacting factors may vary according to cell type. These data suggest that variants occasionally carried by the serum prior to reinfection could be selected toward different compartments of the same infected organism, thus favoring the hypothesis of HCV multiple tropism.

scholarly journals IGF2BP1 Significantly Enhances Translation Efficiency of Duck Hepatitis A Virus Type 1 without Affecting Viral Replication

Biomolecules ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 594 ◽  
Author(s):  
Junhao Chen ◽  
Ruihua Zhang ◽  
Jingjing Lan ◽  
Shaoli Lin ◽  
Pengfei Li ◽  
...  
Keyword(s):  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Protein Accumulation ◽  
Translation Efficiency ◽  
Entry Site ◽  
Positive Role ◽  
Internal Ribosome Entry ◽  
Duck Hepatitis ◽  
Positive Strand Rna

As a disease characterized by severe liver necrosis and hemorrhage, duck viral hepatitis (DVH) is mainly caused by duck hepatitis A virus (DHAV). The positive-strand RNA genome of DHAV type 1 (DHAV-1) contains an internal ribosome entry site (IRES) element within the 5′ untranslated region (UTR), structured sequence elements within the 3′ UTR, and a poly(A) tail at the 3′ terminus. In this study, we first examined that insulin-like growth factor-2 mRNA-binding protein-1 (IGF2BP1) specifically interacted with the DHAV-1 3′ UTR by RNA pull-down assay. The interaction between IGF2BP1 and DHAV-1 3′ UTR strongly enhanced IRES-mediated translation efficiency but failed to regulate DHAV-1 replication in a duck embryo epithelial (DEE) cell line. The viral propagation of DHAV-1 strongly enhanced IGF2BP1 expression level, and viral protein accumulation was identified as the key point to this increment. Collectively, our data demonstrated the positive role of IGF2BP1 in DHAV-1 viral proteins translation and provided data support for the replication mechanism of DHAV-1.

scholarly journals Coding Sequences Enhance Internal Initiation of Translation by Hepatitis A Virus RNA In Vitro

1998 ◽  
Vol 72 (5) ◽  
pp. 3571-3577 ◽  
Author(s):  
Judith Graff ◽  
Ellie Ehrenfeld
Keyword(s):  
Hela Cells ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Productive Infection ◽  
Initiation Codon ◽  
Translation Efficiency ◽  
Coding Sequences ◽  
Cell Extracts ◽  
Initiation Of Translation

ABSTRACT Hepatitis A virus (HAV), unlike other picornaviruses, has a slow-growth phenotype in permissive cell lines and in general does not induce host cell cytopathology. Although there are no published reports of productive infection of HeLa cells by HAV, HAV RNA appears to be readily translated in HeLa cells when transcribed by T7 RNA polymerase provided by a recombinant vaccinia virus. The 5′ noncoding region of HAV was fused to poliovirus (PV) coding sequences to determine the effect on translation efficiency in HeLa cell extracts in vitro. Conditions were optimized for utilization of the HAV internal ribosome entry segment (IRES). Transcripts from chimeric constructs fused precisely at the initiation codon were translated very poorly. However, chimeric RNAs which included 114 or more nucleotides from the HAV capsid coding sequences downstream of the initiation codon were translated much more efficiently than those lacking these sequences, making HAV-directed translation efficiency similar to that directed by the PV IRES. Sixty-six nucleotides were insufficient to confer increased translation efficiency. The most 5′-terminal HAV 138 nucleotides, previously determined to be upstream of the IRES, had an inhibitory effect on translation efficiency. Constructs lacking these terminal sequences, or those in which the PV 5′-terminal sequences replaced those from HAV, translated three- to fourfold better than those with the intact HAV 5′-terminal end.

scholarly journals Advances for the Hepatitis A Virus Antigen Production Using a Virus Strain With Codon Frequency Optimization Adjustments in Specific Locations

2021 ◽  
Vol 12 ◽  
Author(s):  
Gemma Chavarria-Miró ◽  
Montserrat de Castellarnau ◽  
Cristina Fuentes ◽  
Lucía D’Andrea ◽  
Francisco-Javier Pérez-Rodríguez ◽  
...  
Keyword(s):  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Virus Production ◽  
Vero Cells ◽  
Virus Antigen ◽  
Translation Efficiency ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Fast Growing ◽  
Codon Composition

The available cell-adapted hepatitis A virus (HAV) strains show a very slow replication phenotype hampering the affordable production of antigen. A fast-growing strain characterized by the occurrence of mutations in the internal ribosome entry site (IRES), combined with changes in the codon composition has been selected in our laboratory. A characterization of the IRES activity of this fast-growing strain (HM175-HP; HP) vs. its parental strain (HM175; L0) was assessed in two cell substrates used in vaccine production (MRC-5 and Vero cells) compared with the FRhK-4 cell line in which its selection was performed. The HP-derived IRES was significantly more active than the L0-derived IRES in all cells tested and both IRES were more active in the FRhK-4 cells. The translation efficiency of the HP-derived IRES was also much higher than the L0-derived IRES, particularly, in genes with a HP codon usage background. These results correlated with a higher virus production in a shorter time for the HP strain compared to the L0 strain in any of the three cell lines tested, and of both strains in the FRhK-4 cells compared to Vero and MRC-5 cells. The addition of wortmannin resulted in the increase of infectious viruses and antigen in the supernatant of FRhK-4 infected cells, independently of the strain. Finally, the replication of both strains in a clone of FRhK-4 cells adapted to grow with synthetic sera was optimal and again the HP strain showed higher yields.

scholarly journals Activity of the Hepatitis A Virus IRES Requires Association between the Cap-Binding Translation Initiation Factor (eIF4E) and eIF4G

2001 ◽  
Vol 75 (17) ◽  
pp. 7854-7863 ◽  
Author(s):  
Iraj K. Ali ◽  
Linda McKendrick ◽  
Simon J. Morley ◽  
Richard J. Jackson
Keyword(s):  
Translation Initiation ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Direct Interaction ◽  
Binding Pocket ◽  
Translation Initiation Factor ◽  
In Vitro Translation ◽  
Initiation Factor ◽  
Entry Site

ABSTRACT The question of whether translation initiation factor eIF4E and the complete eIF4G polypeptide are required for initiation dependent on the IRES (internal ribosome entry site) of hepatitis A virus (HAV) has been examined using in vitro translation in standard and eIF4G-depleted rabbit reticulocyte lysates. In agreement with previous publications, the HAV IRES is unique among all picornavirus IRESs in that it was inhibited if translation initiation factor eIF4G was cleaved by foot-and-mouth disease L-proteases. In addition, the HAV IRES was inhibited by addition of eIF4E-binding protein 1, which binds tightly to eIF4E and sequesters it, thus preventing its association with eIF4G. The HAV IRES was also inhibited by addition of m7GpppG cap analogue, irrespective of whether the RNA tested was capped or not. Thus, initiation on the HAV IRES requires that eIF4E be associated with eIF4G and that the cap-binding pocket of eIF4E be empty and unoccupied. This suggests two alternative models: (i) initiation requires a direct interaction between an internal site in the IRES and eIF4E/4G, an interaction which involves the cap-binding pocket of eIF4E in addition to any direct eIF4G-RNA interactions; or (ii) it requires eIF4G in a particular conformation which can be attained only if eIF4E is bound to it, with the cap-binding pocket of the eIF4E unoccupied.

“In vitro” and in Animal Model Studies on a Double Virus- Inactivated Factor VIII Concentrate

1995 ◽  
Vol 74 (03) ◽  
pp. 868-873 ◽  
Author(s):  
Silvana Arrighi ◽  
Roberta Rossi ◽  
Maria Giuseppina Borri ◽  
Vladimir Lesnikov ◽  
Marina Lesnikov ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Animal Model ◽  
Factor Viii ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Virus Inactivation ◽  
Enveloped Viruses ◽  
Model Studies ◽  
Heat Treated

SummaryTo improve the safety of plasma derived factor VIII (FVIII) concentrate, we introduced a final super heat treatment (100° C for 30 min) as additional virus inactivation step applied to a lyophilized, highly purified FVIII concentrate (100 IU/mg of proteins) already virus inactivated using the solvent/detergent (SID) method during the manufacturing process.The efficiency of the super heat treatment was demonstrated in inactivating two non-lipid enveloped viruses (Hepatitis A virus and Poliovirus 1). The loss of FVIII procoagulant activity during the super heat treatment was of about 15%, estimated both by clotting and chromogenic assays. No substantial changes were observed in physical, biochemical and immunological characteristics of the heat treated FVIII concentrate in comparison with those of the FVIII before heat treatment.

scholarly journals Individual Expression of Hepatitis A Virus 3C Protease Induces Ferroptosis in Human Cells In Vitro

2021 ◽  
Vol 22 (15) ◽  
pp. 7906
Author(s):  
Alexey A. Komissarov ◽  
Maria A. Karaseva ◽  
Marina P. Roschina ◽  
Andrey V. Shubin ◽  
Nataliya A. Lunina ◽  
...  
Keyword(s):  
Cell Death ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Proteolytic Enzymes ◽  
Morphological Changes ◽  
Human Cells ◽  
Mitochondrial Potential ◽  
3C Protease ◽  
Wide Range

Regulated cell death (RCD) is a fundamental process common to nearly all living beings and essential for the development and tissue homeostasis in animals and humans. A wide range of molecules can induce RCD, including a number of viral proteolytic enzymes. To date, numerous data indicate that picornaviral 3C proteases can induce RCD. In most reported cases, these proteases induce classical caspase-dependent apoptosis. In contrast, the human hepatitis A virus 3C protease (3Cpro) has recently been shown to cause caspase-independent cell death accompanied by previously undescribed features. Here, we expressed 3Cpro in HEK293, HeLa, and A549 human cell lines to characterize 3Cpro-induced cell death morphologically and biochemically using flow cytometry and fluorescence microscopy. We found that dead cells demonstrated necrosis-like morphological changes including permeabilization of the plasma membrane, loss of mitochondrial potential, as well as mitochondria and nuclei swelling. Additionally, we showed that 3Cpro-induced cell death was efficiently blocked by ferroptosis inhibitors and was accompanied by intense lipid peroxidation. Taken together, these results indicate that 3Cpro induces ferroptosis upon its individual expression in human cells. This is the first demonstration that a proteolytic enzyme can induce ferroptosis, the recently discovered and actively studied type of RCD.

scholarly journals Mechanisms of Hepatocellular Injury in Hepatitis A

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 861
Author(s):  
Minghang Wang ◽  
Zongdi Feng
Keyword(s):  
T Cells ◽  
Liver Injury ◽  
Hepatitis A ◽  
Acute Viral Hepatitis ◽  
Hepatitis A Virus ◽  
Current Knowledge ◽  
Cytotoxic T Cells ◽  
Host Factors ◽  
Hepatocellular Injury

Hepatitis A virus (HAV) infection is a common cause of acute viral hepatitis worldwide. Despite decades of research, the pathogenic mechanisms of hepatitis A remain incompletely understood. As the replication of HAV is noncytopathic in vitro, a widely accepted concept has been that virus-specific cytotoxic T cells are responsible for liver injury. However, accumulating evidence suggests that natural killer (NK) cells, NKT cells, and even non-HAV-specific CD8+ T cells contribute to liver damage during HAV infection. In addition, intrinsic death of virus-infected hepatocytes has been implicated as a cause of liver injury in a murine model of hepatitis A. Furthermore, genetic variations in host factors such as T cell immunoglobulin-1 (TIM1) and IL-18 binding protein (IL-18BP) have been linked to hepatitis A severity. This review summarizes the current knowledge of the mechanisms of hepatocellular injury in hepatitis A. Different mechanisms may be involved under different conditions and they are not necessarily mutually exclusive. A better understanding of these mechanisms would aid in diagnosis and treatment of diseases associated with HAV infection.

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