Nonintegrated viral DNA in rat cells doubly transformed by SV40 and polyoma virus.

  title={Nonintegrated viral DNA in rat cells doubly transformed by SV40 and polyoma virus.},
  author={I. Prasad and D. Zouzias and C. Basilico},
  volume={85 1},
Abstract Rat F2408 cells transformed by polyoma virus contain, in addition to integrated viral genomes, a small number (an average of 20–50 copies per cell) of nonintegrated viral DNA molecules. On the other hand, SV40-transformed rat cells contain only integrated viral genomes. SV40-transformed rat cells also differ from the polyoma transformants, in that they grow in soft agar medium at a much slower rate. Cells doubly transformed by polyoma and SV40 can be easily isolated following polyoma… Expand
Polyoma virus middle t antigen: a tumor progression factor
  • R. Seif
  • Medicine, Biology
  • Journal of virology
  • 1980
Middle t antigen enhanced membrane alterations and growth rate of the transformed cells, shortening the time required for tumor formation in rats, and behaved like WT simian virus 40 (SV40). Expand
Persistent BK papovavirus infection of transformed human fetal brain cells. I. Episomal viral DNA in cloned lines deficient in T-antigen expression
Although these cloned cell lines are T- and V-antigen negative when grown in antiserum-containing medium, they retain "free" or episomal BKV genomes; integrated viral DNA was not detected in any of the clones. Expand
Transforming genes and gene products of polyoma and SV40.
The small DNA-containing viruses, SV40 and polyoma, transform cells in vitro and induce tumors in vivo and the genetic and biochemical studies defining the sequences important for transformation will be reviewed. Expand
  • R. Sheinin
  • Biology, Medicine
  • Annals of the New York Academy of Sciences
  • 1981
The mechanism of action of tumor viruses as modifiers of host genome is explored, finding that protected immortality of the virus species is clearly short-lived, in the absence of an infectious virus intermediate which is horizontally transmitted from animal to animal. Expand
The transformation of cell growth and transmogrification of DNA synthesis by simian virus 40.
  • R. Martin
  • Biology, Medicine
  • Advances in cancer research
  • 1981
The hypothesis is that transformation by SV40 unlike PyV is largely explicable in terms of the ability of the 90K T-antigen to initiate DNA synthesis, which can propel the cell into rounds of replication beyond those exhibited by non-transformed cells in the same conditions. Expand
New rat cell line that is highly susceptible to transformation by several oncogenes
We describe here a new cell line, EL2, which spontaneously arose from primary rat embryo fibroblasts and has the distinctive property of being highly susceptible to a number of different transformingExpand
Papovaviral persistent infections
INTRODUCTION................................................................ 385 Variety of Host Responses to Virus Infection....................................... 385 TheExpand


State of the viral DNA in rat cells transformed by polyoma virus. I. Virus rescue and the presence of nonintergrated viral DNA molecules
The interaction of polyoma virus with a continuous line of rat cells was studied, finding that these cells did not produce infectious virus, but in all clones tested virus was rescuable upon fusion with permissive mouse cells. Expand
State of the viral DNA in rat cells transformed by polyma virus. II. Identification of the cells containing nonintegrated viral DNA and the effect of viral mutations
The results suggest that the presence of free viral DNA in polyoma-transformed rat cells is caused by a spontaneous induction of viral DNA replication, occurring with low but constant probability in the transformed cell population, and that the free viralDNA molecules originate from the integrated ones, probably through a phenomenon of excision and limited replication. Expand
Hamster tumor cells doubly transformed by SV40 and polyoma viruses.
In transplantation-resistance tests, approximately 100 times greater cell concentration was required to produce tumors in hamsters previously immunized with polyoma, SV40, or a mixture of both viruses; results indicate that the doubly transformed cells contained the transplantation as well as CF tumor antigens induced by both viruses. Expand
Simian virus 40 integration sites in the genome of virus-transformed mouse cells
The results suggest that the number of stable SV40 integration sites in the 3T3 genome is limited, since they can be saturated by transformation at high MOI, and when the MOI is low, the sites are not saturated and a subsequent infection can lead to integration. Expand
Antigenic and cultural properties of cells doubly transformed by polyoma virus and SV40.
The phenotypes of the doubly transformed lines demonstrate that each of the viruses is capable of acting independently of the other and each may have its distinctive effect on the same host cell. Expand
Factors Influencing the Enhancement of the Infectivity of Poliovirus Ribonucleic Acid by Diethylaminoethyl-Dextran
The enhancement by diethylaminoethyl-dextran (DEAE-D) of the infectivity of poliovirus ribonucleic acid (RNA) for cell cultures was demonstrated by infective-center as well as by plaque assays, bothExpand
Selective extraction of polyoma DNA from infected mouse cell cultures.
  • B. Hirt
  • Chemistry, Medicine
  • Journal of molecular biology
  • 1967