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Biological activity of polyoma viral DNA in mice and hamsters
Abstract:
The biological activity of polyoma viral DNA was evaluated in mice and hamsters. Viral DNA administered parenterally is about 4 to 5 logs less efficient than polyoma virions in establishing infection in mice. Supercoiled viral DNA was infectious for mice after parenteral administration, giving mean infective doses of 10(-3) to 10(-4) microgram. However, animals fed microgram quantities of polyoma DNA I did not become infected. Linearization of viral DNA with R.EcoRI or R.BamHI, which are single-cut enzymes cleaving in the early and late regions of the genome, respectively, reduced the infectivity for mice approximately fivefold. Approximately 10% of newborn hamsters inoculated intraperitoneally with polyoma DNA I developed tumors. In contrast, the same amount of viral DNA which had been cleaved in the early region with R.EcoRI induced tumors in 50% of inoculated hamsters.
Insights
Polyoma viral DNA infectivity and tumor induction were studied in rodents. Supercoiled DNA caused infection in mice, but linearization reduced this. Early region cleavage significantly increased tumor development in hamsters.
Area of Science:
- Virology
- Molecular Biology
- Oncology
Background:
- Polyoma virus is a DNA tumor virus.
- Understanding viral DNA's biological activity is crucial for virology and oncology research.
Purpose of the Study:
- To evaluate the biological activity of polyoma viral DNA in mice and hamsters.
- To compare the infectivity of supercoiled versus linearized viral DNA.
- To assess the oncogenic potential of polyoma viral DNA following different enzymatic treatments.
Main Methods:
- Parenteral administration of polyoma viral DNA (supercoiled and linearized) to mice.
- Oral administration of polyoma viral DNA to mice.
- Intraperitoneal inoculation of newborn hamsters with polyoma viral DNA.
- Enzymatic cleavage of polyoma viral DNA using R.EcoRI and R.BamHI.
Main Results:
- Parenteral administration of viral DNA was less efficient than virions for mouse infection.
- Supercoiled viral DNA was infectious in mice, with mean infective doses of 10(-3) to 10(-4) microgram.
- Linearization of viral DNA reduced infectivity in mice approximately fivefold.
- Intraperitoneal inoculation of polyoma DNA I induced tumors in 10% of newborn hamsters.
- Cleavage in the early region (R.EcoRI) increased tumor induction in hamsters to 50%.
Conclusions:
- Supercoiled polyoma viral DNA exhibits infectivity in mice after parenteral administration.
- Linearization of polyoma viral DNA significantly reduces its infectivity in mice.
- Cleavage of polyoma viral DNA within the early region enhances its oncogenic potential in hamsters.