scholarly journals Eukaryotic transient-expression system based on recombinant vaccinia virus that synthesizes bacteriophage T7 RNA polymerase.

1986 ◽  
Vol 83 (21) ◽  
pp. 8122-8126 ◽  
Author(s):  
T. R. Fuerst ◽  
E. G. Niles ◽  
F. W. Studier ◽  
B. Moss
Keyword(s):  
Rna Polymerase ◽  
Vaccinia Virus ◽  
Transient Expression ◽  
Expression System ◽  
Recombinant Vaccinia Virus ◽  
T7 Rna Polymerase ◽  
Bacteriophage T7 ◽  
Recombinant Vaccinia ◽  
Transient Expression System

scholarly journals Use of a hybrid vaccinia virus-T7 RNA polymerase system for expression of target genes.

1987 ◽  
Vol 7 (7) ◽  
pp. 2538-2544 ◽  
Author(s):  
T R Fuerst ◽  
P L Earl ◽  
B Moss
Keyword(s):  
Rna Polymerase ◽  
Vaccinia Virus ◽  
Target Gene ◽  
Target Genes ◽  
Expression System ◽  
Recombinant Vaccinia Virus ◽  
T7 Rna Polymerase ◽  
Bacteriophage T7 ◽  
Virus Surface ◽  
Recombinant Vaccinia

A novel expression system based on coinfection of cells with two recombinant vaccinia viruses has been developed. One recombinant vaccinia virus contained the bacteriophage T7 RNA polymerase gene under control of a vaccinia virus promoter. The second recombinant vaccinia virus contained a target gene of choice flanked by bacteriophage T7 promoter and termination sequences. Maximum expression of the target gene occurred when cells were infected with 10 PFU of each recombinant virus. Although T7 RNA polymerase synthesis began shortly after infection, the target gene was not expressed until late times and was largely inhibited when DNA replication was blocked. Target gene transcripts were analyzed by agarose gel electrophoresis and had the predicted size. With this system, Escherichia coli beta-galactosidase, hepatitis B virus surface antigen, and human immunodeficiency virus envelope proteins were made. In each case, the level of synthesis was greater than had previously been obtained with the more conventional recombinant vaccinia virus expression system.

Use of a hybrid vaccinia virus-T7 RNA polymerase system for expression of target genes

1987 ◽  
Vol 7 (7) ◽  
pp. 2538-2544
Author(s):  
T R Fuerst ◽  
P L Earl ◽  
B Moss
Keyword(s):  
Rna Polymerase ◽  
Vaccinia Virus ◽  
Target Gene ◽  
Target Genes ◽  
Expression System ◽  
Recombinant Vaccinia Virus ◽  
T7 Rna Polymerase ◽  
Bacteriophage T7 ◽  
Virus Surface ◽  
Recombinant Vaccinia

A novel expression system based on coinfection of cells with two recombinant vaccinia viruses has been developed. One recombinant vaccinia virus contained the bacteriophage T7 RNA polymerase gene under control of a vaccinia virus promoter. The second recombinant vaccinia virus contained a target gene of choice flanked by bacteriophage T7 promoter and termination sequences. Maximum expression of the target gene occurred when cells were infected with 10 PFU of each recombinant virus. Although T7 RNA polymerase synthesis began shortly after infection, the target gene was not expressed until late times and was largely inhibited when DNA replication was blocked. Target gene transcripts were analyzed by agarose gel electrophoresis and had the predicted size. With this system, Escherichia coli beta-galactosidase, hepatitis B virus surface antigen, and human immunodeficiency virus envelope proteins were made. In each case, the level of synthesis was greater than had previously been obtained with the more conventional recombinant vaccinia virus expression system.

scholarly journals Development of Cell-Based Assays for In Vitro Characterization of Hepatitis C Virus NS3/4A Protease Inhibitors

2005 ◽  
Vol 49 (4) ◽  
pp. 1381-1390 ◽  
Author(s):  
Victoria Chung ◽  
Anthony R. Carroll ◽  
Norman M. Gray ◽  
Nigel R. Parry ◽  
Pia A. Thommes ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Vaccinia Virus ◽  
Protease Inhibitors ◽  
Expression System ◽  
Recombinant Vaccinia Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Recombinant Vaccinia

ABSTRACT A recombinant vaccinia virus, expressing the NS3-to-NS5 region of the N clone of hepatitis C virus (HCV), was generated and utilized both in a gel-based assay and in an enzyme-linked immunosorbent assay (ELISA) to evaluate the pyrrolidine-5,5-trans-lactams, a series of inhibitors of the HCV NS3/4A protease. The absolute levels of processed, mature HCV nonstructural proteins in this system were found to decrease in the presence of the trans-lactams. Monitoring of this reduction enabled end points and 50% inhibitory concentrations to be calculated in order to rank the active compounds according to potency. These compounds had no effect on the transcription or translation of the NS3-5 polyprotein at concentrations shown to inhibit NS3/4A protease, and they were shown to be specific inhibitors of this protease. The ELISA, originally developed using the vaccinia virus expression system, was modified to utilize Huh-7 cells containing an HCV replicon. Results with this assay correlated well with those obtained with the recombinant vaccinia virus assays. These results demonstrate the utility of these assays for the characterization of NS3/4A protease inhibitors. In addition, inhibitors of other viral targets, such as polymerase and helicase, can be evaluated in the context of the replicon ELISA.

scholarly journals Engineering efficient termination of bacteriophage T7 RNA polymerase transcription

2021 ◽  
Author(s):  
Diana Gabriela Calvopina Chavez ◽  
Mikaela Anne Gardner ◽  
Joel S Griffitts
Keyword(s):  
Rna Polymerase ◽  
Molecular Level ◽  
Expression System ◽  
T7 Rna Polymerase ◽  
Bacteriophage T7 ◽  
Lower Efficiency ◽  
Transcriptional Termination ◽  
T7 Polymerase

The bacteriophage T7 expression system is one of the most prominent transcription systems used in biotechnology and molecular-level research. However, T7 RNA polymerase is prone to read-through transcription due to its high processivity. As a consequence, enforcing efficient transcriptional termination is difficult. The termination hairpin found natively in the T7 genome is adapted to be inefficient, exhibiting 62% termination efficiency in vivo and even lower efficiency in vitro. In this study, we engineered a series of sequences that outperform the efficiency of the native terminator hairpin. By embedding a previously discovered 8-nucleotide T7 polymerase pause sequence within a synthetic hairpin sequence, we observed in vivo termination efficiency of 91%; by joining two short sequences into a tandem 2-hairpin structure, termination efficiency was increased to 98% in vivo and 91% in vitro. This study also tests the ability of these engineered sequences to terminate transcription of the Escherichia coli RNA polymerase. Two out of three of the most successful T7 polymerase terminators also facilitated termination of the bacterial polymerase with around 99% efficiency.

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