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Mapping of a mouse mammary tumor virus integration site by retroviral LTR--arbitrary polymerase chain reaction
C Casper1, C Leib-Mösch, B Salmons
1GSF-Centre for Environmental and Health Research, Institute of Pathology, Oberschleissheim, Germany.
Abstract:
The de novo integration of retroviral genomes within the mammalian genome is believed to contribute to the tumorigenic process. Integration may result in the disruption or inappropriate transcription of key regulatory genes. We describe the application of an arbitrarily primed PCR method for the mapping and cloning of genomic integration sites of the mouse mammary tumor virus (MMTV). We have amplified DNA sequences between a selected retroviral MMTV-LTR and random sites in the 3' flanking DNA. Using this technique we were able to visualize several proviral integration sites present in a MMTV-induced mammary tumor derived cell line that were absent from the germ line. Cloning and sequencing of the PCR product corresponding to one site established its identification as an unique 3' flanking sequence.
Insights
This study introduces a new PCR method to map mouse mammary tumor virus (MMTV) integration sites in mammalian genomes. This technique helps identify MMTV's role in tumor development by pinpointing viral DNA insertions.
Area of Science:
- Molecular Biology
- Virology
- Oncology
Background:
- Retroviral genome integration into the mammalian genome is implicated in cancer development.
- Integration can disrupt critical regulatory genes, contributing to tumorigenesis.
Purpose of the Study:
- To develop and apply a novel arbitrarily primed PCR method for mapping and cloning MMTV genomic integration sites.
- To identify specific MMTV integration events in tumor-derived cell lines.
Main Methods:
- Arbitrarily primed PCR was used to amplify DNA sequences between the MMTV long terminal repeat (LTR) and flanking genomic DNA.
- Integration sites were visualized, cloned, and sequenced.
Main Results:
- The PCR method successfully identified multiple MMTV proviral integration sites in a tumor cell line.
- These integration sites were absent in the germ line DNA, indicating de novo integration events.
- Sequencing confirmed one integration site corresponded to a unique 3' flanking genomic sequence.
Conclusions:
- Arbitrarily primed PCR is an effective technique for mapping MMTV integration sites.
- Identifying these sites provides insights into MMTV-induced tumorigenesis.
- This method facilitates the study of retroviral integration in cancer research.