Cryo-Electron Microscopy and Image Analysis of SV40

1985 ◽  
Vol 43 ◽  
pp. 316-317
Author(s):  
T. S. Baker ◽  
J. Drak ◽  
M. Bina
Keyword(s):  
Electron Microscopy ◽  
Simian Virus 40 ◽  
Carbon Support ◽  
Simian Virus ◽  
Thin Layers ◽  
Sv40 Virus ◽  
Virus Particles ◽  
Frozen Solution ◽  
Cryo Electron Microscopy ◽  
Icosahedral Capsid

The discovery that the T=7 icosahedral capsid of polyoma virus is composed of 72 pentameric capsomers rather than 12 pentamers and 60 hexamers as predicted by constraints of quasi-equivalence has prompted an examination of SV40 virus by electron microscopy to determine whether the capsids of other members of the papovavirus family are similarly constructed.Thin layers of buffered aqueous solutions (∼4 mg/ml) of Simian virus 40 (strain WT776) were prepared for cryo-microscopy using recently developed procedures. Images of virus particles suspended in thin layers of vitreous ice over holes in the carbon support film and maintained at -170°C were recorded using minimal irradiation conditions. Figure 1 shows a typical field in which the frozen solution is similar in thickness to the virus particles (∼49 nm diameter). Particles appear to be excluded or squeezed away from the thinnest regions of solution (e.g., the clear region bordered by particles at the top of Fig. 1).

Electron Microscopic Observations on the Rescue of SV40 Virus From Transformed Cells

1972 ◽  
Vol 30 ◽  
pp. 278-279
Author(s):  
Ronald Glaser ◽  
Ross Farrugia
Keyword(s):  
Electron Microscopy ◽  
Cell Fusion ◽  
Sendai Virus ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Transformed Cells ◽  
Density Gradients ◽  
Electron Microscopic ◽  
Sv40 Virus ◽  
Virus Particles

Several laboratories have reported that simian virus 40 (SV40) was rescued from transformed cells when the nonproducing cells were cocultivated or fused in the presence of ultraviolet inactivated Sendai virus (UV-SV), to potentially susceptible cells. Evidence obtained from studies in which nuclei from heterokaryons were isolated and separated on density gradients, indicated that rescued virus was first detected in the transformed nuclei of the heterokaryons formed during cell fusion. The present study was performed to determine how long after fusion SV40 virus particles could be found in the nuclei of the heterokaryons and to investigate the site of rescue by electron microscopy.

Tumor promoter 12-O-tetradecanoylphorbol 13-acetate stimulates simian virus 40 induction by DNA-damaging agents and tumor initiators

1983 ◽  
Vol 3 (5) ◽  
pp. 757-760
Author(s):  
S Nomura ◽  
N Shobu ◽  
M Oishi
Keyword(s):  
Molecular Structure ◽  
Uv Irradiation ◽  
Culture Medium ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Tumor Promoter ◽  
Kidney Cells ◽  
Sv40 Virus ◽  
Virus Particles ◽  
Dna Damaging Agents

Simian virus 40 (SV40)-transformed Syrian hamster kidney cells produce infectious SV40 virus particles after treatments which damage DNA, such as UV irradiation or mitomycin C treatment. We have found that the induction of SV40 by DNA-damaging agents is greatly stimulated when a typical tumor promoter, 12-O-tetradecanoylphorbol 13-acetate (TPA), is present in the medium. Phorbol, which has a molecular structure similar to TPA but does not have any tumor-promoting activity, showed no such stimulatory effect on SV40 induction. This apparent synergistic effect of DNA-damaging agents and tumor promoter (TPA) was more pronounced when a tumor initiator, benzo [a]pyrene or 2-acetamido-fluorene, was combined with TPA. The effect of TPA on UV-triggered SV40 induction was greatly influenced by the timing of TPA addition to the culture medium, which was most efficient when addition of TPA was 5 to 20 h before UV irradiation. The effect of TPA, however, was not observed in SV40 rescue from hamster cells by cell fusion with permissive monkey (C7) cells.

scholarly journals Tumor promoter 12-O-tetradecanoylphorbol 13-acetate stimulates simian virus 40 induction by DNA-damaging agents and tumor initiators.

1983 ◽  
Vol 3 (5) ◽  
pp. 757-760 ◽  
Author(s):  
S Nomura ◽  
N Shobu ◽  
M Oishi
Keyword(s):  
Molecular Structure ◽  
Uv Irradiation ◽  
Culture Medium ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Tumor Promoter ◽  
Kidney Cells ◽  
Sv40 Virus ◽  
Virus Particles ◽  
Dna Damaging Agents

Simian virus 40 (SV40)-transformed Syrian hamster kidney cells produce infectious SV40 virus particles after treatments which damage DNA, such as UV irradiation or mitomycin C treatment. We have found that the induction of SV40 by DNA-damaging agents is greatly stimulated when a typical tumor promoter, 12-O-tetradecanoylphorbol 13-acetate (TPA), is present in the medium. Phorbol, which has a molecular structure similar to TPA but does not have any tumor-promoting activity, showed no such stimulatory effect on SV40 induction. This apparent synergistic effect of DNA-damaging agents and tumor promoter (TPA) was more pronounced when a tumor initiator, benzo [a]pyrene or 2-acetamido-fluorene, was combined with TPA. The effect of TPA on UV-triggered SV40 induction was greatly influenced by the timing of TPA addition to the culture medium, which was most efficient when addition of TPA was 5 to 20 h before UV irradiation. The effect of TPA, however, was not observed in SV40 rescue from hamster cells by cell fusion with permissive monkey (C7) cells.

Microinjected simian virus 40 cRNA is spliced, as evidenced by electron microscopy.

1983 ◽  
Vol 48 (1) ◽  
pp. 296-299 ◽  
Author(s):  
M Graessmann ◽  
A Graessmann ◽  
H Westphal
Keyword(s):  
Electron Microscopy ◽  
Simian Virus 40 ◽  
Simian Virus

scholarly journals Enhancement of DNA-mediated gene transfer by high-Mr carrier DNA in synchronized CV-1 cells

1985 ◽  
Vol 225 (2) ◽  
pp. 529-533 ◽  
Author(s):  
A J Strain ◽  
W A H Wallace ◽  
A H Wyllie
Keyword(s):  
Cell Cycle ◽  
Gene Transfer ◽  
Transfection Efficiency ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
S Phase ◽  
Sv40 Virus ◽  
G2 Phase ◽  
Cycle Dependent ◽  
Sv40 Dna

Synchronized CV-1 cells were transfected with SV40 (simian virus 40) DNA-calcium phosphate co-precipitates. In the presence of carrier DNA, the transfection efficiency of SV40 DNA was decreased 5-fold in S-phase cells and was increased 4-fold in preparations of mitotically enriched cells as compared with asynchronous controls. No difference was observed when carrier DNA was omitted, when cells had progressed through S-phase and into G2-phase, or when the infectivity of cells to intact SV40 virus was tested. These results highlight the importance of cell-cycle-dependent factors on DNA-mediated gene transfer.

[8] Electron microscopy of simian virus 40 minichromosomes

1989 ◽  
pp. 166-179
Author(s):  
Pierre Oudet ◽  
Patrick Schultz ◽  
Jean-Claude Homo ◽  
Pierre Colin
Keyword(s):  
Electron Microscopy ◽  
Simian Virus 40 ◽  
Simian Virus

scholarly journals Enhanced transformation by a simian virus 40 recombinant virus containing a Harvey murine sarcoma virus long terminal repeat.

1983 ◽  
Vol 3 (3) ◽  
pp. 325-339 ◽  
Author(s):  
M Kriegler ◽  
M Botchan
Keyword(s):  
Long Terminal Repeat ◽  
Recombinant Virus ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Viral Dna ◽  
Sv40 Virus ◽  
Transformed Cell ◽  
Murine Sarcoma Virus ◽  
Sarcoma Virus ◽  
Murine Sarcoma

We have constructed a recombinant simian virus 40 (SV40) DNA containing a copy of the Harvey murine sarcoma virus long terminal repeat (LTR). This recombinant viral DNA was converted into an infectious SV40 virus particle and subsequently infected into NIH 3T3 cells (either uninfected or previously infected with Moloney leukemia virus). We found that this hybrid virus, SVLTR1, transforms cells with 10 to 20 times the efficiency of SV40 wild type. Southern blot analysis of these transformed cell genomic DNAs revealed that simple integration of the viral DNA within the retrovirus LTR cannot account for the enhanced transformation of the recombinant virus. A restriction fragment derived from the SVLTR-1 virus which contains an intact LTR was readily identified in a majority of the transformed cell DNAs. These results suggest that the LTR fragment which contains the attachment sites and flanking sequences for the proviral DNA duplex may be insufficient by itself to facilitate correct retrovirus integration and that some other functional element of the LTR is responsible for the increased transformation potential of this virus. We have found that a complete copy of the Harvey murine sarcoma virus LTR linked to well-defined structural genes lacking their own promoters (SV40 early region, thymidine kinase, and G418 resistance) can be effectively used to promote marker gene expression. To determine which element of the LTR served to enhance the biological activity of the recombinant virus described above, we deleted DNA sequences essential for promoter activity within the LTR. SV40 virus stocks reconstructed with this mutated copy of the Harvey murine sarcoma virus LTR still transform mouse cells at an enhanced frequency. We speculate that when the LTR is placed more than 1.5 kilobases from the SV40 early promoter, the cis-acting enhancer element within the LTR can increase the ability of the SV40 promoter to effectively operate when integrated in a murine chromosome. These data are discussed in terms of the apparent cell specificity of viral enhancer elements.

scholarly journals Cryo-electron Microscopy Structures of Novel Viruses from Mud Crab Scylla paramamosain with Multiple Infections

2019 ◽  
Vol 93 (7) ◽  
Author(s):  
Yuanzhu Gao ◽  
Shanshan Liu ◽  
Jiamiao Huang ◽  
Qianqian Wang ◽  
Kunpeng Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
3D Structure ◽  
Structural Features ◽  
Economic Losses ◽  
Scylla Paramamosain ◽  
Multiple Infections ◽  
Mud Crab ◽  
Cryo Electron Microscopy ◽  
Novel Virus ◽  
Icosahedral Capsid

ABSTRACT Viruses associated with sleeping disease (SD) in crabs cause great economic losses to aquaculture, and no effective measures are available for their prevention. In this study, to help develop novel antiviral strategies, single-particle cryo-electron microscopy was applied to investigate viruses associated with SD. The results not only revealed the structure of mud crab dicistrovirus (MCDV) but also identified a novel mud crab tombus-like virus (MCTV) not previously detected using molecular biology methods. The structure of MCDV at a 3.5-Å resolution reveals three major capsid proteins (VP1 to VP3) organized into a pseudo-T=3 icosahedral capsid, and affirms the existence of VP4. Unusually, MCDV VP3 contains a long C-terminal region and forms a novel protrusion that has not been observed in other dicistrovirus. Our results also reveal that MCDV can release its genome via conformation changes of the protrusions when viral mixtures are heated. The structure of MCTV at a 3.3-Å resolution reveals a T= 3 icosahedral capsid with common features of both tombusviruses and nodaviruses. Furthermore, MCTV has a novel hydrophobic tunnel beneath the 5-fold vertex and 30 dimeric protrusions composed of the P-domains of the capsid protein at the 2-fold axes that are exposed on the virion surface. The structural features of MCTV are consistent with a novel type of virus. IMPORTANCE Pathogen identification is vital for unknown infectious outbreaks, especially for dual or multiple infections. Sleeping disease (SD) in crabs causes great economic losses to aquaculture worldwide. Here we report the discovery and identification of a novel virus in mud crabs with multiple infections that was not previously detected by molecular, immune, or traditional electron microscopy (EM) methods. High-resolution structures of pathogenic viruses are essential for a molecular understanding and developing new disease prevention methods. The three-dimensional (3D) structure of the mud crab tombus-like virus (MCTV) and mud crab dicistrovirus (MCDV) determined in this study could assist the development of antiviral inhibitors. The identification of a novel virus in multiple infections previously missed using other methods demonstrates the usefulness of this strategy for investigating multiple infectious outbreaks, even in humans and other animals.

Assemblages of simian virus 40 capsid proteins and viral DNA visualized by electron microscopy

2007 ◽  
Vol 353 (2) ◽  
pp. 424-430 ◽  
Author(s):  
Vered Roitman-Shemer ◽  
Jitka Stokrova ◽  
Jitka Forstova ◽  
Ariella Oppenheim
Keyword(s):  
Electron Microscopy ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Capsid Proteins ◽  
Viral Dna
Sign in / Sign up

Export Citation Format

Share Document