Generation and Characterization of recombinant SARS-CoV-2 expressing reporter genes

AbstractThe emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pathogen responsible of coronavirus disease 2019 (COVID-19), has devastated public health services and economies worldwide. Despite global efforts to contain the COVID-19 pandemic, SARS-CoV-2 is now found in over 200 countries and has caused an upward death toll of over 1 million human lives as of November 2020. To date, only one Food and Drug Administration (FDA)-approved therapeutic drug (Remdesivir) and a monoclonal antibody, MAb (Bamlanivimab), but no vaccines, are available for the treatment of SARS-CoV-2. As with other viruses, studying SARS-CoV-2 requires the use of secondary approaches to detect the presence of the virus in infected cells. To overcome this limitation, we have generated replication-competent recombinant (r)SARS-CoV-2 expressing fluorescent (Venus or mCherry) or bioluminescent (Nluc) reporter genes. Vero E6 cells infected with reporter-expressing rSARS-CoV-2 can be easily detected via fluorescence or luciferase expression and display a good correlation between reporter gene expression and viral replication. Moreover, rSARS-CoV-2 expressing reporter genes have comparable plaque sizes and growth kinetics to those of wild-type virus, rSARS-CoV-2/WT. We used these reporter-expressing rSARS-CoV-2 to demonstrate their feasibility to identify neutralizing antibodies (NAbs) or antiviral drugs. Our results demonstrate that reporter-expressing rSARS-CoV-2 represent an excellent option to identify therapeutics for the treatment of SARS-CoV-2, where reporter gene expression can be used as valid surrogates to track viral infection. Moreover, the ability to manipulate the viral genome opens the feasibility of generating viruses expressing foreign genes for their use as vaccines for the treatment of SARS-CoV-2 infection.ImportanceSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pathogen that causes coronavirus disease 2019 (COVID-19), has significantly impacted the human health and economic status worldwide. There is an urgent need to identify effective prophylactics and therapeutics for the treatment of SARS-CoV-2 infection and associated COVID-19 disease. The use of fluorescent- or luciferase-expressing reporter expressing viruses has significantly advanced viral research. Here, we generated recombinant (r)SARS-CoV-2 expressing fluorescent (Venus and mCherry) or luciferase (Nluc) reporter genes and demonstrate that they represent an excellent option to track viral infections in vitro. Importantly, reporter-expressing rSARS-CoV-2 display similar growth kinetics and plaque phenotype that their wild-type counterpart (rSARS-CoV-2/WT), demonstrating their feasibility to identify drugs and/or neutralizing antibodies (NAbs) for the therapeutic treatment of SARS-CoV-2. Henceforth, these reporter-expressing rSARS-CoV-2 can be used to interrogate large libraries of compounds and/or monoclonal antibodies (MAb), in high-throughput screening settings, to identify those with therapeutic potential against SARS-CoV-2.

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Generation and Characterization of recombinant SARS-CoV-2 expressing reporter genes

Journal of Virology ◽

10.1128/jvi.02209-20 ◽

2021 ◽

Cited By ~ 1

Author(s):

Kevin Chiem ◽

Desarey Morales Vasquez ◽

Jun-Gyu Park ◽

Roy Neal Platt ◽

Tim Anderson ◽

...

Keyword(s):

Gene Expression ◽

Severe Acute Respiratory Syndrome ◽

Reporter Gene ◽

Growth Kinetics ◽

Neutralizing Antibodies ◽

Reporter Genes ◽

Reporter Gene Expression ◽

Wild Type Virus ◽

Luciferase Expression ◽

Wild Type

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pathogen responsible of coronavirus disease 2019 (COVID-19), has devastated public health services and economies worldwide. Despite global efforts to contain the COVID-19 pandemic, SARS-CoV-2 is now found in over 200 countries and has caused an upward death toll of over 1 million human lives as of November 2020. To date, only one Food and Drug Administration (FDA)-approved therapeutic drug (Remdesivir) and a monoclonal antibody, MAb (Bamlanivimab) are available for the treatment of SARS-CoV-2. As with other viruses, studying SARS-CoV-2 requires the use of secondary approaches to detect the presence of the virus in infected cells. To overcome this limitation, we have generated replication-competent recombinant (r)SARS-CoV-2 expressing fluorescent (Venus or mCherry) or bioluminescent (Nluc) reporter genes. Vero E6 cells infected with reporter-expressing rSARS-CoV-2 can be easily detected via fluorescence or luciferase expression and display a good correlation between reporter gene expression and viral replication. Moreover, rSARS-CoV-2 expressing reporter genes have comparable plaque sizes and growth kinetics to those of wild-type virus, rSARS-CoV-2/WT. We used these reporter-expressing rSARS-CoV-2 to demonstrate their feasibility to identify neutralizing antibodies (NAbs) or antiviral drugs. Our results demonstrate that reporter-expressing rSARS-CoV-2 represent an excellent option to identify therapeutics for the treatment of SARS-CoV-2, where reporter gene expression can be used as valid surrogates to track viral infection. Moreover, the ability to manipulate the viral genome opens the feasibility of generating viruses expressing foreign genes for their use as vaccines for the treatment of SARS-CoV-2 infection. IMPORTANCE Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pathogen that causes coronavirus disease 2019 (COVID-19), has significantly impacted the human health and economic status worldwide. There is an urgent need to identify effective prophylactics and therapeutics for the treatment of SARS-CoV-2 infection and associated COVID-19 disease. The use of fluorescent- or luciferase-expressing reporter expressing viruses has significantly advanced viral research. Here, we generated recombinant (r)SARS-CoV-2 expressing fluorescent (Venus and mCherry) or luciferase (Nluc) reporter genes and demonstrate that they represent an excellent option to track viral infections in vitro. Importantly, reporter-expressing rSARS-CoV-2 display similar growth kinetics and plaque phenotype that their wild-type counterpart (rSARS-CoV-2/WT), demonstrating their feasibility to identify drugs and/or neutralizing antibodies (NAbs) for the therapeutic treatment of SARS-CoV-2. Henceforth, these reporter-expressing rSARS-CoV-2 can be used to interrogate large libraries of compounds and/or monoclonal antibodies (MAb), in high-throughput screening settings, to identify those with therapeutic potential against SARS-CoV-2.

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Cross regulation of decapentaplegic and Ultrabithorax transcription in the embryonic visceral mesoderm of Drosophila

Development ◽

10.1242/dev.117.4.1211 ◽

1993 ◽

Vol 117 (4) ◽

pp. 1211-1222 ◽

Cited By ~ 20

Author(s):

D.A. Hursh ◽

R.W. Padgett ◽

W.M. Gelbart

Keyword(s):

Gene Expression ◽

Signal Transduction ◽

Family Member ◽

Reporter Gene ◽

Expression Patterns ◽

Reporter Genes ◽

Regulatory Elements ◽

Wild Type ◽

Visceral Mesoderm ◽

Normal Expression

The Drosophila decapentaplegic gene (dpp) encodes a TGF-beta family member involved in signal transduction during embryonic midgut formation. The shortvein (shv) class of cis-regulatory dpp mutants disrupt expression in parasegments 4 and 7 (ps4 and ps7) of the embryonic visceral mesoderm (VM) surrounding the gut and cause abnormalities in gut morphogenesis. We demonstrate that cis-regulatory elements directing expression in ps4 and ps7 are separable and identify DNA fragments that generate ps4 and ps7 expression patterns using reporter gene constructs. dpp reporter gene expression in both ps4 and ps7 is autoregulated as it requires endogenous dpp+ activity. Reporter gene ps7 expression requires the wild-type action of Ultra-bithorax (Ubx), and abdominal-A. Furthermore, the expression of certain Ubx reporter genes is coincident with dpp in the VM. Both the mis-expression of Ubx reporter genes in the developing gastric caecae at ps4 and its normal expression in ps7 are dependent upon endogenous dpp+ activity. We conclude that dpp both responds to and regulates Ubx in ps7 of the visceral mesoderm and that Ubx autoregulation within this tissue may be indirect as it requires more components than have previously been thought.

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CG dinucleotide removal in bioluminescent and fluorescent reporters improves HIV-1 replication and reporter gene expression for dual imaging in humanized mice

Journal of Virology ◽

10.1128/jvi.00449-21 ◽

2021 ◽

Author(s):

Chandra N. Roy ◽

Mariana A. Benitez Moreno ◽

Chris Kline ◽

Zandrea Ambrose

Keyword(s):

Gene Expression ◽

Reporter Gene ◽

Reporter Genes ◽

Reporter Gene Expression ◽

Humanized Mice ◽

Plasma Viremia ◽

Reporter Expression ◽

Cg Dinucleotides ◽

Hiv 1

Visualizing the transmission and dissemination of human immunodeficiency virus type 1 (HIV-1) in real time in humanized mouse models is a robust tool to investigate viral replication during treatments and in tissue reservoirs. However, the stability and expression of HIV-1 reporter genes are obstacles for long-term serial imaging in vivo . Two replication-competent CCR5-tropic HIV-1 reporter constructs were created that encode either nanoluciferase (nLuc) or a near - infrared fluorescent protein (iRFP) upstream of nef . HIV-1 reporter virus replication and reporter gene expression was measured in cell culture and in humanized mice. While reporter gene expression in vivo correlated initially with plasma viremia, expression decreased after 4-5 weeks despite high plasma viremia. The reporter genes were codon-optimized to remove cytosine/guanine (CG) dinucleotides and new CO-nLuc and CO-iRFP viruses were reconstructed. Removal of CG dinucleotides in HIV-1 reporter viruses improved replication in vitro and reporter expression in vivo and ex vivo . Both codon optimized reporter viruses could be visualized during co-infection and in vivo reporter gene expression during treatment failure preceded detection of plasma viremia. While the dynamic range of CO-iRFP HIV-1 was lower than that of CO-nLuc HIV-1, both viruses could have utility in studying and visualizing HIV-1 infection in humanized mice. Importance Animal models are important for studying HIV-1 pathogenesis and treatments. We developed two viruses each encoding a reporter gene that can be expressed in cells after infection. This study shows that HIV-1 infection can be visualized by noninvasive, whole body imaging in mice with human immune cells over time by reporter expression. We improved reporter expression to reflect HIV-1 replication and showed that two viral variants can be tracked over time in the same animal and can predict failure of antiretroviral therapy to suppress virus.

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Imaging Reporters and Multimodal Molecular Bio-Imaging: A Database of Available Probes for Multi-Modality Bio-Imaging of Reporter Gene Expression

Recent Patents on Medical Imaging ◽

10.2174/1877613211202010006 ◽

2012 ◽

Vol 2 (1) ◽

pp. 6-22

Author(s):

Rakesh Sharma ◽

Avdhesh Sharma ◽

Ching J. Chen

Keyword(s):

Gene Expression ◽

Reporter Gene ◽

Reporter Gene Expression ◽

Bio Imaging

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Kinetics of Neutralizing Antibodies of COVID-19 Patients Tested Using Clinical D614G, B.1.1.7 and B 1.351 Isolates in Microneutralization Assays

Viruses ◽

10.3390/v13060996 ◽

2021 ◽

Vol 13 (6) ◽

pp. 996

Author(s):

Jenni Virtanen ◽

Ruut Uusitalo ◽

Essi M. Korhonen ◽

Kirsi Aaltonen ◽

Teemu Smura ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Acute Infection ◽

Clinical Isolates ◽

Wild Type Virus ◽

Type Virus ◽

Wild Type ◽

Kinetics Of

Increasing evidence suggests that some newly emerged SARS-CoV-2 variants of concern (VoCs) resist neutralization by antibodies elicited by the early-pandemic wild-type virus. We applied neutralization tests to paired recoveree sera (n = 38) using clinical isolates representing the first wave (D614G), VoC1, and VoC2 lineages (B.1.1.7 and B 1.351). Neutralizing antibodies inhibited contemporary and VoC1 lineages, whereas inhibition of VoC2 was reduced 8-fold, with 50% of sera failing to show neutralization. These results provide evidence for the increased potential of VoC2 to reinfect previously SARS-CoV-infected individuals. The kinetics of NAbs in different patients showed similar decline against all variants, with generally low initial anti-B.1.351 responses becoming undetectable, but with anti-B.1.1.7 NAbs remaining detectable (>20) for months after acute infection.

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