scholarly journals Semliki Forest virus-derived virus-like particles: characterization of their production and transduction pathways

2005 ◽  
Vol 86 (11) ◽  
pp. 3129-3136 ◽  
Author(s):  
A. Diatta ◽  
E. Piver ◽  
C. Collin ◽  
P. Vaudin ◽  
J.-C. Pagès
Keyword(s):  
Molecular Mechanisms ◽  
Semliki Forest Virus ◽  
Target Cells ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Replication Complex ◽  
Virus Like Particles ◽  
Vesicular Stomatitis ◽  
Viral Envelopes

A procedure for the mobilization of Semliki Forest virus (SFV)-derived replicons using virus-like particles (VLPs) has been recently proposed. VLPs were obtained from 293T cells co-expressing the vesicular stomatitis virus glycoprotein (VSV-G) and a modified SFV replicon. Advantages of SFV VLPs include improved safety with a lack of sequence homology between components and reducing the risk of recombination events that could lead to the formation of autonomous particles. Characterization of SFV VLPs reveals a discrepancy in their ability to infect cells reported to be permissive. Furthermore, it was noted that not all viral envelopes were able to promote VLP release equally from transfected cells. These observations encouraged the examination of the molecular mechanisms supporting the different steps of VLP assembly and transduction. The use of a VSV-G related pathway for VLP entry into target cells was demonstrated; it was also observed that an internal ribosome entry site may not be adapted to control transgene expression in all cells. Finally, the need for a membrane-binding domain to obtain a fully active SFV replication complex and VLP formation was documented.

scholarly journals BDNF-induced local translation of GluA1 is regulated by HNRNP A2/B1

2020 ◽  
Vol 6 (47) ◽  
pp. eabd2163
Author(s):  
Youngseob Jung ◽  
Ji-Young Seo ◽  
Hye Guk Ryu ◽  
Do-Yeon Kim ◽  
Kyung-Ha Lee ◽  
...  
Keyword(s):  
Ampa Receptor ◽  
Molecular Mechanisms ◽  
Receptor Expression ◽  
Spine Density ◽  
Entry Site ◽  
Independent Manner ◽  
Internal Ribosome Entry ◽  
Ampa Receptor Subunit ◽  
Internal Initiation ◽  
Underlying Mechanisms

The AMPA receptor subunit GluA1 is essential for induction of synaptic plasticity. While various regulatory mechanisms of AMPA receptor expression have been identified, the underlying mechanisms of GluA1 protein synthesis are not fully understood. In neurons, axonal and dendritic mRNAs have been reported to be translated in a cap-independent manner. However, molecular mechanisms of cap-independent translation of synaptic mRNAs remain largely unknown. Here, we show that GluA1 mRNA contains an internal ribosome entry site (IRES) in the 5′UTR. We also demonstrate that heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 interacts with GluA1 mRNA and mediates internal initiation of GluA1. Brain-derived neurotrophic factor (BDNF) stimulation increases IRES-mediated GluA1 translation via up-regulation of HNRNP A2/B1. Moreover, BDNF-induced GluA1 expression and dendritic spine density were significantly decreased in neurons lacking hnRNP A2/B1. Together, our data demonstrate that IRES-mediated translation of GluA1 mRNA is a previously unidentified feature of local expression of the AMPA receptor.

scholarly journals Virological characterization of the hepatitis C virus JFH-1 strain in lymphocytic cell lines

2008 ◽  
Vol 89 (7) ◽  
pp. 1587-1592 ◽  
Author(s):  
Kyoko Murakami ◽  
Toshiro Kimura ◽  
Motonao Osaki ◽  
Koji Ishii ◽  
Tatsuo Miyamura ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Cell Lines ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Culture Systems ◽  
Polyprotein Processing ◽  
Lymphocytic Cell

While hepatocytes are the major site of hepatitis C virus (HCV) infection, a number of studies have suggested that HCV can replicate in lymphocytes. However, in vitro culture systems to investigate replication of HCV in lymphocytic cells are severely limited. Robust HCV culture systems have been established using the HCV JFH-1 strain and Huh-7 cells. To gain more insights into the tissue tropism of HCV, we investigated the infection, replication, internal ribosome entry site (IRES)-dependent translation and polyprotein processing of the HCV JFH-1 strain in nine lymphocytic cell lines. HCV JFH-1 failed to infect lymphocytes and replicate, but exhibited efficient polyprotein processing and IRES-dependent translation in lymphocytes as well as in Huh-7 cells. Our results suggest that lymphocytic cells can support HCV JFH-1 translation and polyprotein processing, but may lack some host factors essential for HCV JFH-1 infection and replication.

scholarly journals Identification and Characterization of a Novel Cell Cycle–Regulated Internal Ribosome Entry Site

2000 ◽  
Vol 5 (4) ◽  
pp. 597-605 ◽  
Author(s):  
Sigrid Cornelis ◽  
Yanik Bruynooghe ◽  
Geertrui Denecker ◽  
Sofie Van Huffel ◽  
Sandrine Tinton ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Internal Ribosome Entry Site ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Identification And Characterization

scholarly journals Comparative Molecular Biology Approaches for the Production of Poliovirus Virus-Like Particles Using Pichia pastoris

mSphere ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Lee Sherry ◽  
Keith Grehan ◽  
Joseph S. Snowden ◽  
Michael L. Knight ◽  
Oluwapelumi O. Adeyemi ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Expression System ◽  
Rhopalosiphum Padi ◽  
Genetic Material ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Content Type ◽  
Virus Like Particles ◽  
Wild Poliovirus ◽  
Dimensional Classification

ABSTRACT For enteroviruses such as poliovirus (PV), empty capsids, which are antigenically indistinguishable from mature virions, are produced naturally during viral infection. The production of such capsids recombinantly, in heterologous systems such as yeast, have great potential as virus-like particle (VLP) vaccine candidates. Here, using PV as an exemplar, we show the production of VLPs in Pichia pastoris by coexpression of the structural precursor protein P1 and the viral protease 3CD. The level of expression of the potentially cytotoxic protease relative to that of the P1 precursor was modulated by three different approaches: expression of the P1 precursor and protease from different transcription units, separation of the P1 and protease proteins using the Thosea asigna virus (TaV) 2A translation interruption sequence, or separation of the P1 and protease-coding sequences by an internal ribosome entry site sequence from Rhopalosiphum padi virus (RhPV). We also investigate the antigenicity of VLPs containing previously characterized mutations when produced in Pichia. Finally, using transmission electron microscopy and two-dimensional classification, we show that Pichia-derived VLPs exhibited the classical icosahedral capsid structure displayed by enteroviruses. IMPORTANCE Although the current poliovirus immunization program has been extremely successful in reducing the number of cases of paralytic polio worldwide, now more cases are caused by vaccine-derived polioviruses than by wild poliovirus. Switching to inactivated poliovirus vaccines will reduce this over time; however, their production requires the growth of large amounts of virus. This biosafety concern can be addressed by producing just the virus capsid. The capsid serves to protect the genetic material, which causes disease when introduced into a cell. Therefore, empty capsids (virus-like particles [VLPs]), which lack the viral RNA genome, are safe both to make and to use. We exploit yeast as a versatile model expression system to produce VLPs, and here we specifically highlight the potential of this system to supply next-generation poliovirus vaccines to secure a polio-free world for the future.

scholarly journals Heterogeneous Nuclear Ribonucleoprotein L Negatively Regulates Foot-and-Mouth Disease Virus Replication through Inhibition of Viral RNA Synthesis by Interacting with the Internal Ribosome Entry Site in the 5′ Untranslated Region

2020 ◽  
Vol 94 (10) ◽  
Author(s):  
Chao Sun ◽  
Mengmeng Liu ◽  
Jitao Chang ◽  
Decheng Yang ◽  
Bo Zhao ◽  
...  
Keyword(s):  
Rna Synthesis ◽  
Foot And Mouth Disease ◽  
Viral Rna ◽  
Dependent Manner ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Replication Complex ◽  
Mouth Disease Virus ◽  
Nuclear Ribonucleoprotein ◽  
Fmdv Replication

ABSTRACT Upon infection, the highly structured 5′ untranslated region (5′ UTR) of picornavirus is involved in viral protein translation and RNA synthesis. As a critical element in the 5′ UTR, the internal ribosome entry site (IRES) binds to various cellular proteins to function in the processes of picornavirus replication. Foot-and-mouth disease virus (FMDV) is an important member in the family Picornaviridae, and its 5′ UTR contains a functional IRES element. In this study, the cellular heterogeneous nuclear ribonucleoprotein L (hnRNP L) was identified as an IRES-binding protein for FMDV by biotinylated RNA pulldown assays, mass spectrometry (MS) analysis, and determination of hnRNP L-IRES interaction regions. Further, we found that hnRNP L inhibited the growth of FMDV through binding to the viral IRES and that the inhibitory effect of hnRNP L on FMDV growth was not due to FMDV IRES-mediated translation, but to influence on viral RNA synthesis. Finally, hnRNP L was demonstrated to coimmunoprecipitate with RNA-dependent RNA polymerase (3Dpol) in an FMDV RNA-dependent manner in the infected cells. Thus, our results suggest that hnRNP L, as a critical IRES-binding protein, negatively regulates FMDV replication by inhibiting viral RNA synthesis, possibly by remaining in the replication complex. IMPORTANCE Picornaviruses, as a large family of human and animal pathogens, cause a bewildering array of disease syndromes. Many host factors are implicated in the pathogenesis of these viruses, and some proteins interact with the viral IRES elements to affect function. Here, we report for the first time that cellular hnRNP L specifically interacts with the IRES of the picornavirus FMDV and negatively regulates FMDV replication through inhibiting viral RNA synthesis. Further, our results showed that hnRNP L coimmunoprecipitates with FMDV 3Dpol in a viral RNA-dependent manner, suggesting that it may remain in the replication complex to function. The data presented here would facilitate further understanding of virus-host interactions and the pathogenesis of picornavirus infections.

scholarly journals A Dormant Internal Ribosome Entry Site Controls Translation of Feline Immunodeficiency Virus

2008 ◽  
Vol 82 (7) ◽  
pp. 3574-3583 ◽  
Author(s):  
Valentina Camerini ◽  
Didier Decimo ◽  
Laurent Balvay ◽  
Mauro Pistello ◽  
Mauro Bendinelli ◽  
...  
Keyword(s):  
Feline Immunodeficiency Virus ◽  
In Vitro Translation ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Immunodeficiency Virus ◽  
Specific Stimulation ◽  
Dependent Mechanism

ABSTRACT The characterization of internal ribosome entry sites (IRESs) in virtually all lentiviruses prompted us to investigate the mechanism used by the feline immunodeficiency virus (FIV) to produce viral proteins. Various in vitro translation assays with mono- and bicistronic constructs revealed that translation of the FIV genomic RNA occurred both by a cap-dependent mechanism and by weak internal entry of the ribosomes. This weak IRES activity was confirmed in feline cells expressing bicistronic RNAs containing the FIV 5′ untranslated region (UTR). Surprisingly, infection of feline cells with FIV, but not human immunodeficiency virus type 1, resulted in a great increase in FIV translation. Moreover, a change in the cellular physiological condition provoked by heat stress resulted in the specific stimulation of expression driven by the FIV 5′ UTR while cap-dependent initiation was severely repressed. These results reveal the presence of a “dormant” IRES that becomes activated by viral infection and cellular stress.

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