scholarly journals The utility of siRNA transcripts produced by RNA polymerase i in down regulating viral gene expression and replication of negative- and positive-strand RNA viruses

Virology ◽  
2003 ◽  
Vol 313 (2) ◽  
pp. 514-524 ◽  
Author(s):  
Matthew McCown ◽  
Michael S Diamond ◽  
Andrew Pekosz
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Rna Viruses ◽  
Viral Gene Expression ◽  
Rna Polymerase I ◽  
Viral Gene ◽  
Positive Strand ◽  
Positive Strand Rna ◽  
Polymerase I

scholarly journals New insights into internal ribosome entry site elements relevant for viral gene expression

2008 ◽  
Vol 89 (3) ◽  
pp. 611-626 ◽  
Author(s):  
Encarnación Martínez-Salas ◽  
Almudena Pacheco ◽  
Paula Serrano ◽  
Noemi Fernandez
Keyword(s):  
Gene Expression ◽  
Rna Binding ◽  
Viral Gene Expression ◽  
Rna Replication ◽  
Host Factors ◽  
Viral Gene ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Positive Strand ◽  
Positive Strand Rna

A distinctive feature of positive-strand RNA viruses is the presence of high-order structural elements at the untranslated regions (UTR) of the genome that are essential for viral RNA replication. The RNA of all members of the family Picornaviridae initiate translation internally, via an internal ribosome entry site (IRES) element present in the 5′ UTR. IRES elements consist of cis-acting RNA structures that usually require specific RNA-binding proteins for translational machinery recruitment. This specialized mechanism of translation initiation is shared with other viral RNAs, e.g. from hepatitis C virus and pestivirus, and represents an alternative to the cap-dependent mechanism. In cells infected with many picornaviruses, proteolysis or changes in phosphorylation of key host factors induces shut off of cellular protein synthesis. This event occurs simultaneously with the synthesis of viral gene products since IRES activity is resistant to the modifications of the host factors. Viral gene expression and RNA replication in positive-strand viruses is further stimulated by viral RNA circularization, involving direct RNA–RNA contacts between the 5′ and 3′ ends as well as RNA-binding protein bridges. In this review, we discuss novel insights into the mechanisms that control picornavirus gene expression and compare them to those operating in other positive-strand RNA viruses.

scholarly journals Production of Infectious Hepatitis C Virus by Using RNA Polymerase I-Mediated Transcription

2010 ◽  
Vol 84 (11) ◽  
pp. 5824-5835 ◽  
Author(s):  
Takahiro Masaki ◽  
Ryosuke Suzuki ◽  
Mohsan Saeed ◽  
Ken-ichi Mori ◽  
Mami Matsuda ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Rna Polymerase ◽  
Cell Line ◽  
Viral Genome ◽  
Rna Polymerase I ◽  
Virion Assembly ◽  
Pol I ◽  
Positive Strand Rna ◽  
Polymerase I

ABSTRACT In this study, we used an RNA polymerase I (Pol I) transcription system for development of a reverse genetics protocol to produce hepatitis C virus (HCV), which is an uncapped positive-strand RNA virus. Transfection with a plasmid harboring HCV JFH-1 full-length cDNA flanked by a Pol I promoter and Pol I terminator yielded an unspliced RNA with no additional sequences at either end, resulting in efficient RNA replication within the cytoplasm and subsequent production of infectious virions. Using this technology, we developed a simple replicon trans-packaging system, in which transient transfection of two plasmids enables examination of viral genome replication and virion assembly as two separate steps. In addition, we established a stable cell line that constitutively produces HCV with a low mutation frequency of the viral genome. The effects of inhibitors of N-linked glycosylation on HCV production were evaluated using this cell line, and the results suggest that certain step(s), such as virion assembly, intracellular trafficking, and secretion, are potentially up- and downregulated according to modifications of HCV envelope protein glycans. This Pol I-based HCV expression system will be beneficial for a high-throughput antiviral screening and vaccine discovery programs.

RNA polymerase I-mediated protein-coding gene expression in Trypanosoma brucei

1992 ◽  
Vol 8 (12) ◽  
pp. 414-418 ◽  
Author(s):  
H-M. Chung ◽  
M.G-S. Lee ◽  
L.H.T. Van der Ploeg
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Trypanosoma Brucei ◽  
Rna Polymerase I ◽  
Protein Coding ◽  
Polymerase I

scholarly journals RNA polymerase I promoter and splice acceptor site recognition affect gene expression in non-pathogenic Leishmania species

2007 ◽  
Vol 102 (7) ◽  
pp. 891-894 ◽  
Author(s):  
Tereza Cristina Orlando ◽  
Mário Gustavo Mayer ◽  
David A Campbell ◽  
Nancy R Sturm ◽  
Lucile Maria Floeter-Winter
Keyword(s):  
Gene Expression ◽  
Rna Polymerase ◽  
Leishmania Species ◽  
Rna Polymerase I ◽  
Splice Acceptor Site ◽  
Acceptor Site ◽  
Splice Acceptor ◽  
Polymerase I ◽  
Site Recognition ◽  
Affect Gene Expression

scholarly journals Norovirus gene expression and replication

2014 ◽  
Vol 95 (2) ◽  
pp. 278-291 ◽  
Author(s):  
Lucy G. Thorne ◽  
Ian G. Goodfellow
Keyword(s):  
Gene Expression ◽  
Molecular Mechanisms ◽  
Rna Viruses ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Genome Replication ◽  
Murine Norovirus ◽  
Technological Advances ◽  
Viral Genome Replication ◽  
Cell Processes

Noroviruses are small, positive-sense RNA viruses within the family Caliciviridae, and are now accepted widely as a major cause of acute gastroenteritis in both developed and developing countries. Despite their impact, our understanding of the life cycle of noroviruses has lagged behind that of other RNA viruses due to the inability to culture human noroviruses (HuNVs). Our knowledge of norovirus biology has improved significantly over the past decade as a result of numerous technological advances. The use of a HuNV replicon, improved biochemical and cell-based assays, combined with the discovery of a murine norovirus capable of replication in cell culture, has improved greatly our understanding of the molecular mechanisms of norovirus genome translation and replication, as well as the interaction with host cell processes. In this review, the current state of knowledge of the intracellular life of noroviruses is discussed with particular emphasis on the mechanisms of viral gene expression and viral genome replication.

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