scholarly journals Linear simian virus 40 DNA fragments exhibit a propensity for rolling-circle replication.

1985 ◽  
Vol 5 (7) ◽  
pp. 1787-1790 ◽  
Author(s):  
I Deichaite ◽  
Z Laver-Rudich ◽  
D Dorsett ◽  
E Winocour
Keyword(s):  
Electron Microscopy ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Dna Fragments ◽  
Rolling Circle Replication ◽  
Supercoiled Dna ◽  
Rolling Circle ◽  
Cos Cells ◽  
Dna Fragment ◽  
Replication Intermediates

A linear simian virus 40 origin-containing DNA fragment replicated in monkey COS cells, generating tandemly repeated (head-to-tail) structures. Electron microscopy revealed circle-and-tail configurations characteristic of rolling-circle replication intermediates. Circularization of the same DNA before transfection led to a theta type of replication which generated supercoiled DNA molecules.

Linear simian virus 40 DNA fragments exhibit a propensity for rolling-circle replication

1985 ◽  
Vol 5 (7) ◽  
pp. 1787-1790
Author(s):  
I Deichaite ◽  
Z Laver-Rudich ◽  
D Dorsett ◽  
E Winocour
Keyword(s):  
Electron Microscopy ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Dna Fragments ◽  
Rolling Circle Replication ◽  
Supercoiled Dna ◽  
Rolling Circle ◽  
Cos Cells ◽  
Dna Fragment ◽  
Replication Intermediates

A linear simian virus 40 origin-containing DNA fragment replicated in monkey COS cells, generating tandemly repeated (head-to-tail) structures. Electron microscopy revealed circle-and-tail configurations characteristic of rolling-circle replication intermediates. Circularization of the same DNA before transfection led to a theta type of replication which generated supercoiled DNA molecules.

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 In vivo competition of delta-crystallin gene expression by DNA fragments containing a GC box.

1986 ◽  
Vol 6 (11) ◽  
pp. 4130-4132 ◽  
Author(s):  
S Hayashi ◽  
H Kondoh
Keyword(s):  
Gene Expression ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Dna Fragments ◽  
Specific Expression ◽  
Mouse Cells ◽  
Gc Box ◽  
Simplex Virus

Expression of the chicken delta-crystallin gene 1 injected into the nuclei of mouse cells is lens specific. Coinjection of GC box-containing DNA fragments from delta-crystallin, simian virus 40 early, and herpes simplex virus type 1 tk promoters effectively suppressed delta-crystallin expression in the lens, but coinjection with DNA fragments not containing the GC box did not. This suppression was likely due to the competition of an Sp1-like transcription factor(s) and indicates involvement of the apparently ubiquitous factor(s) in the tissue-specific expression of the delta-crystallin gene.

Preparation of a "functional library" of African green monkey DNA fragments which substitute for the processing/polyadenylation signal in the herpes simplex virus type 1 thymidine kinase gene

1983 ◽  
Vol 3 (4) ◽  
pp. 643-653
Author(s):  
G M Santangelo ◽  
C N Cole
Keyword(s):  
Gene Expression ◽  
Thymidine Kinase ◽  
Low Frequency ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
African Green Monkey ◽  
Dna Fragments ◽  
Coding Region ◽  
Kinase Gene ◽  
Green Monkey

Fragments of African green monkey (Cercopithecus aethiops) DNA (3.5 to 18.0 kilobases) were inserted downstream from the thymidine kinase (TK, tk) coding region in pTK206/SV010, a gene construct which lacks both copies of the hexanucleotide 5'-AATAAA-3' and contains a simian virus 40 origin of replication, allowing it to replicate in Cos-1 cells. No polyadenylated tk mRNA was detected in Cos-1 cells transfected by pTK206/SV010. The ability of simian DNA fragments to restore tk gene expression was examined by measuring the incorporation of [125I]iododeoxycytidine into DNA in Cos-1 cells transfected by pTK206/SV010 insertion derivatives. tk gene expression was restored by the insertion in 56 of the 67 plasmids analyzed, and the level of expression equaled or exceeded that obtained with the wild-type tk gene in 30 of these. In all plasmids examined that showed restoration of tk gene expression, polyadenylated tk mRNA of discrete size was detected. The sizes of these tk mRNAs were consistent with the existence of processing and polyadenylation signals within the inserted DNA fragments. The frequency with which inserted fragments restored tk gene expression suggests that the minimal signal for processing and polyadenylation is a hexanucleotide (AAUAAA or a similar sequence). LTK- cells were biochemically transformed to TK+ with representative insertion constructs. pTK206/SV010 transformed LTK- cells at a very low frequency; the frequency of transformation with insertion derivatives was 40 to 12,000 times higher.

scholarly journals Expression of the chicken c-src gene in COS cells

1984 ◽  
Vol 4 (5) ◽  
pp. 846-851
Author(s):  
T M Gilmer
Keyword(s):  
Rous Sarcoma Virus ◽  
Recombinant Plasmid ◽  
Expression System ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Cos Cells ◽  
Rous Sarcoma ◽  
Src Gene ◽  
Cellular Homolog ◽  
Sarcoma Virus

The cellular homolog of the Rous sarcoma virus transforming gene (v-src) was cloned into a plasmid containing the simian virus 40 origin of replication and transcriptional signals. This recombinant plasmid, designated pSVOHCS11 , directs the synthesis of relatively high levels of c-src mRNA and c-src protein ( pp60c -src), when the plasmid is studied 48 to 72 h after calcium phosphate-mediated DNA transfection of COS (monkey) cells. The level of c-src mRNA synthesis is 50-fold higher than the amount of c-src RNA produced in uninfected chicken embryo fibroblasts. Furthermore, the level of pp60c -src expressed in pSVOHCS11 -transfected COS cells is approximately the same as that of pp60v -src in Rous sarcoma virus-transformed cells. Using this recombinant plasmid, we demonstrated that c-src mRNA contains sequences which map 3' to the previously identified c-src-v-src regions of homology. In view of the small amount of c-src mRNA and protein that can be isolated from uninfected cells, this transient expression system offers a convenient source of material for further analyses of the c-src gene product.

scholarly journals Subcellular Localization and Rolling Circle Replication of Peach Latent Mosaic Viroid: Hallmarks of Group A Viroids

1999 ◽  
Vol 73 (8) ◽  
pp. 6353-6360 ◽  
Author(s):  
F. Bussière ◽  
J. Lehoux ◽  
D. A. Thompson ◽  
L. J. Skrzeczkowski ◽  
J.-P. Perreault
Keyword(s):  
Subcellular Localization ◽  
Cellular Level ◽  
Symmetric Mode ◽  
Rolling Circle Replication ◽  
Dot Blot ◽  
Rolling Circle ◽  
Group A ◽  
Group B ◽  
Contrast Group ◽  
Replication Intermediates

ABSTRACT We characterized the peach latent mosaic viroid (PLMVd) replication intermediates that accumulate in infected peach leaves and determined the tissue and subcellular localization of the RNA species. Using in situ hybridization, we showed that PLMVd strands of both plus and minus polarities concentrate in the cells forming the palisade parenchyma. At the cellular level, PLMVd was found to accumulate predominantly in chloroplasts. Northern blot analyses demonstrated that PLMVd replicates via a symmetric mode involving the accumulation of both circular and linear monomeric strands of both polarities. No multimeric conformer was detected, indicating that both strands self-cleave efficiently via their hammerhead sequences. Dot blot hybridizations revealed that PLMVd strands of both polarities accumulate equally but that the relative concentrations vary by more than 50-fold between peach cultivars. Taken together these results establish two hallmarks for the classification of viroids. Group A viroids (e.g., PLMVd), which possess hammerhead structures, replicate in the chloroplasts via the symmetric mode. By contrast, group B viroids, which share a conserved central region, replicate in the nucleus via an asymmetric mechanism. This is an important difference between self-cleaving and non-self-cleaving viroids, and the implications for the evolutionary origin and replication are discussed.

[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

Circular and linear simian virus 40 DNAs differ in recombination

1985 ◽  
Vol 5 (4) ◽  
pp. 869-880
Author(s):  
D Dorsett ◽  
I Deichaite ◽  
E Winocour
Keyword(s):  
Dna Sequences ◽  
Tandem Repeats ◽  
Regulatory Region ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
T Antigen ◽  
Linear Forms ◽  
Rolling Circle ◽  
Linear Dna ◽  
Sv40 Dna

Linear forms of simian virus 40 (SV40) DNA, when added to transfection mixtures containing circular SV40 and phi X174 RFI DNAs, enhanced the frequency of SV40/phi X174 recombination, as measured by infectious center in situ plaque hybridization in monkey BSC-1 cells. The sequences required for the enhancement of recombination by linear DNA reside within the SV40 replication origin/regulatory region (nucleotides 5,171 to 5,243/0 to 128). Linearization of phi X174 RFI DNA did not increase the recombination frequency. The SV40/phi X174 recombinant structures arising from transfections supplemented with linear forms of origin-containing SV40 DNA contained phi X174 DNA sequences interspersed within tandem head-to-tail repeats derived from the recombination-enhancing linear DNA. Evidence is presented that the tandem repeats are not formed by homologous recombination and that linear forms of SV40 DNA must compete with circular SV40 DNA for the available T antigen to enhance recombination. We propose that the enhancement of recombination by linear SV40 DNA results from the entry of that DNA into a rolling circle type of replication pathway which generates highly recombinogenic intermediates.

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