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Detection of acquired provirus sequences in mammary tumors from low-expressor, low-risk mice
Abstract:
Murine mammary tumor virus (MuMTV) provirus sequences in the DNA from early-occurring (average age 10 mo) and late occurring (age greater than 20 mo) tumors in BALB/cfC3H mice were analyzed by Eco RI restriction endonuclease mapping procedures. All early tumors were MuMTV antigen-positive mammary adenocarcinomas that contained the 0.92- and 4.0-kilo base (kb) exogenous C3H MuMTV-specific Pst I restriction endonuclease fragments. All but 1 of the late mammary adenocarcinomas had MuMTV antigens detected by peroxidase antiperoxidase staining, and all contained the 0.92- and 4.0-kb exogenous virus Pst I fragments. Three late nonmammary tumors lacked both MuMTV antigens and acquired provirus sequences. Greater numbers of MuMTV sequences were detected in both early and late-arising mammary tumors by Eco RI restriction endonuclease mapping than were detected in tissues from uninfected BALB/c mice. However, neither the number nor the location of MuMTV proviruses correlated with tumor latent period.
Insights
Murine mammary tumor virus (MuMTV) provirus sequences were analyzed in mouse tumors. The presence of MuMTV sequences did not correlate with tumor development time.
Area of Science:
- Virology
- Oncology
- Genetics
Background:
- Murine mammary tumor virus (MuMTV) is associated with mammary tumors in mice.
- Understanding the role of MuMTV provirus integration is crucial for cancer research.
Purpose of the Study:
- To investigate the presence and characteristics of MuMTV provirus sequences in early and late-occurring tumors.
- To determine if MuMTV provirus number or location correlates with tumor latency.
Main Methods:
- Analysis of MuMTV provirus sequences using Eco RI restriction endonuclease mapping.
- Detection of MuMTV antigens via peroxidase antiperoxidase staining.
- Comparison of provirus sequences in mammary tumors, nonmammary tumors, and uninfected tissues.
Main Results:
- All early mammary tumors and most late mammary tumors contained specific MuMTV provirus fragments.
- Greater numbers of MuMTV sequences were found in mammary tumors compared to uninfected tissues.
- No correlation was observed between MuMTV provirus quantity/location and tumor latent period.
Conclusions:
- MuMTV provirus sequences are present in both early and late-onset mammary tumors.
- The integration pattern of MuMTV does not predict tumor development timing.