Rate of DNA chain growth in mammalian cells infected with cytocidal RNA viruses

Virology ◽  
1972 ◽  
Vol 47 (2) ◽  
pp. 331-337 ◽  
Author(s):  
Roger Hand ◽  
Igor Tamm
Keyword(s):  
Mammalian Cells ◽  
Rna Viruses ◽  
Chain Growth ◽  
Dna Chain

scholarly journals DNA REPLICATION: DIRECTION AND RATE OF CHAIN GROWTH IN MAMMALIAN CELLS

1973 ◽  
Vol 58 (2) ◽  
pp. 410-418 ◽  
Author(s):  
Roger Hand ◽  
Igor Tamm
Keyword(s):  
Dna Replication ◽  
Mammalian Cells ◽  
Thymidine Incorporation ◽  
Specific Activity ◽  
High Specific Activity ◽  
Chain Elongation ◽  
Prolonged Treatment ◽  
Chain Growth ◽  
The Common ◽  
Dna Chain

Using pulse labeling techniques with [3H]thymidine or [3H]cytidine, combined with DNA fiber autoradiography, we have investigated the direction and rate of DNA chain growth in mammalian cells. In general, chain elongation proceeds bidirectionally from the common origin of pairs of adjacent replication sections. This type of replication is noted whether the DNA is labeled first with [3H]thymidine of high specific activity, followed by [3H]thymidine of low specific activity or the sequence is reversed. Approximately one-fifth of the growing points have unique origins and in these replication units, chain growth proceeds in one direction only. Fluorodeoxyuridine and hydroxyurea both inhibit DNA chain propagation. Fluorodeoxyuridine exerts its effect on chain growth within 15–23 min, while the effect of hydroxyurea is evident within 15 min under conditions where the endogenous thymidine pool has been depleted by prior treatment with fluorodeoxyuridine. Puromycin has no effect on chain growth until 60 min after addition of the compound, even though thymidine incorporation is more than 50% reduced within 15 min. After 2 h of treatment with puromycin, the rate of chain growth is reduced by 50%, whereas thymidine incorporation is reduced by 75%. Cycloheximide reduces the rates of DNA chain growth and thymidine incorporation 50% within 15 min, and, on prolonged treatment, the decrease in rate of chain growth generally parallels the reduction in thymidine incorporation.

scholarly journals BPIFB3 interacts with ARFGAP1 and TMED9 to regulate non-canonical autophagy and RNA virus infection

2020 ◽  
pp. jcs.251835
Author(s):  
Azia S. Evans ◽  
Nicholas J. Lennemann ◽  
Carolyn B. Coyne
Keyword(s):  
Mass Spectrometry ◽  
Mammalian Cells ◽  
Viral Infections ◽  
Rna Viruses ◽  
Rna Virus ◽  
Negative Regulator ◽  
Host Factors ◽  
Important Negative Regulator ◽  
Cellular Components

Autophagy is a degradative cellular pathway that targets cytoplasmic contents and organelles for turnover by the lysosome. Various autophagy pathways play key roles in the clearance of viral infections, and many families of viruses have developed unique methods for avoiding degradation. Some positive stranded RNA viruses, such as enteroviruses and flaviviruses, usurp the autophagic pathway to promote their own replication. We previously identified the endoplasmic reticulum-localized protein BPIFB3 as an important negative regulator of non-canonical autophagy that uniquely impacts the replication of enteroviruses and flaviviruses. Here, we find that many components of the canonical autophagy machinery are not required for BPIFB3 depletion induced autophagy and identify the host factors that facilitate its role in the replication of enteroviruses and flaviviruses. Using proximity-dependent biotinylation (BioID) followed by mass spectrometry, we identify ARFGAP1 and TMED9 as two cellular components that interact with BPIFB3 to regulate autophagy and viral replication. Importantly, our data demonstrate that non-canonical autophagy in mammalian cells can be controlled outside of the traditional pathway regulators and define the role of two proteins in BPIFB3 depletion mediated non-canonical autophagy.

Detecting RNA viruses in living mammalian cells by fluorescence microscopy

2011 ◽  
Vol 29 (7) ◽  
pp. 307-313 ◽  
Author(s):  
Divya Sivaraman ◽  
Payal Biswas ◽  
Lakshmi N. Cella ◽  
Marylynn V. Yates ◽  
Wilfred Chen
Keyword(s):  
Fluorescence Microscopy ◽  
Mammalian Cells ◽  
Rna Viruses

Intermediate in SV40 DNA Chain Growth

1972 ◽  
Vol 238 (87) ◽  
pp. 274-277 ◽  
Author(s):  
GEORGE C. FAREED ◽  
NORMAN P. SALZMAN
Keyword(s):  
Chain Growth ◽  
Dna Chain ◽  
Sv40 Dna

Endogenous type-C RNA viruses of mammalian cells

1976 ◽  
Vol 458 (4) ◽  
pp. 323-354 ◽  
Author(s):  
Stuart A. Aaronson ◽  
John R. Stephenson
Keyword(s):  
Mammalian Cells ◽  
Rna Viruses ◽  
Type C

scholarly journals Synthetic antibodies neutralize SARS-CoV-2 infection of mammalian cells

2020 ◽  
Author(s):  
Shane Miersch ◽  
Mart Ustav ◽  
Zhijie Li ◽  
James B. Case ◽  
Safder Ganaie ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Severe Acute Respiratory Syndrome ◽  
Receptor Binding ◽  
Mammalian Cells ◽  
Rna Viruses ◽  
Large Family ◽  
Spike Protein ◽  
Receptor Binding Domain ◽  
Highly Pathogenic ◽  
Zoonotic Infections

ABSTRACTCoronaviruses (CoV) are a large family of enveloped, RNA viruses that circulate in mammals and birds. Three highly pathogenic strains have caused zoonotic infections in humans that result in severe respiratory syndromes including the Middle East Respiratory Syndrome CoV (MERS), Severe Acute Respiratory Syndrome CoV (SARS), and the ongoing Coronavirus Disease 2019 (COVID-19) pandemic. Here, we describe a panel of synthetic monoclonal antibodies, built on a human IgG framework, that bind to the spike protein of SARS-CoV-2 (the causative agent of COVID-19), compete for ACE2 binding, and potently inhibit SARS-CoV-2. All antibodies that exhibited neutralization potencies at sub-nanomolar concentrations against SARS-CoV-2/USA/WA1 in Vero E6 cells, also bound to the receptor binding domain (RBD), suggesting competition for the host receptor ACE2. These antibodies represent strong immunotherapeutic candidates for treatment of COVID-19.

scholarly journals The Capsid Protein of Semliki Forest Virus Antagonizes RNA Interference in Mammalian Cells

2019 ◽  
Vol 94 (3) ◽  
Author(s):  
Qi Qian ◽  
Hui Zhou ◽  
Ting Shu ◽  
Jingfang Mu ◽  
Yuan Fang ◽  
...  
Keyword(s):  
Rna Interference ◽  
Capsid Protein ◽  
Mammalian Cells ◽  
Semliki Forest Virus ◽  
Rna Viruses ◽  
Strong Support ◽  
Life Cycles ◽  
Immune Defense ◽  
Rnai Pathway ◽  
Viral Suppressors

ABSTRACT RNA interference (RNAi) is a conserved antiviral immune defense in eukaryotes, and numerous viruses have been found to encode viral suppressors of RNAi (VSRs) to counteract antiviral RNAi. Alphaviruses are a large group of positive-stranded RNA viruses that maintain their transmission and life cycles in both mosquitoes and mammals. However, there is little knowledge about how alphaviruses antagonize RNAi in both host organisms. In this study, we identified that Semliki Forest virus (SFV) capsid protein can efficiently suppress RNAi in both insect and mammalian cells by sequestrating double-stranded RNA and small interfering RNA. More importantly, when the VSR activity of SFV capsid was inactivated by reverse genetics, the resulting VSR-deficient SFV mutant showed severe replication defects in mammalian cells, which could be rescued by blocking the RNAi pathway. Besides, capsid protein of Sindbis virus also inhibited RNAi in cells. Together, our findings show that SFV uses capsid protein as VSR to antagonize RNAi in infected mammalian cells, and this mechanism is probably used by other alphaviruses, which shed new light on the knowledge of SFV and alphavirus. IMPORTANCE Alphaviruses are a genus of positive-stranded RNA viruses and include numerous important human pathogens, such as Chikungunya virus, Ross River virus, Western equine encephalitis virus, etc., which create the emerging and reemerging public health threat worldwide. RNA interference (RNAi) is one of the most important antiviral mechanisms in plants and insects. Accumulating evidence has provided strong support for the existence of antiviral RNAi in mammals. In response to antiviral RNAi, viruses have evolved to encode viral suppressors of RNAi (VSRs) to antagonize the RNAi pathway. It is unclear whether alphaviruses encode VSRs that can suppress antiviral RNAi during their infection in mammals. In this study, we first uncovered that capsid protein encoded by Semliki Forest virus (SFV), a prototypic alphavirus, had a potent VSR activity that can antagonize antiviral RNAi in the context of SFV infection in mammalian cells, and this mechanism is probably used by other alphaviruses.

Sign in / Sign up

Export Citation Format

Share Document