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Polyoma integrates readily in mouse cellular DNA
1Département de Microbiologie, Faculté de Médecine, Université de Sherbrooke, Québec, Canada.
Abstract:
Although the natural host of polyoma virus is the mouse, its integration in cellular DNA has been investigated almost exclusively in rat cells. We report here studies on the integration of polyoma in mouse cells. We introduced the polyoma virus genome in two different mouse cell lines as an unselected genetic marker, by cotransfection with the tk gene of herpes simplex virus or the neo gene of E. coli. The number of TK+ or G418R clones obtained was reduced up to 50 fold by the presence of the polyoma genome. The gene coding for the early protein large T of polyoma was necessary and sufficient to produce this reduction. However, this effect appeared to be independent of polyoma replication. Surprisingly, all of the 33 clones analysed that had survived cotransfection with polyoma contained polyoma DNA integrated in their genome. Furthermore, in over 50% of these clones, the entire polyoma genome had been integrated. We conclude that polyoma integrates readily in mouse cellular DNA.
Insights
Polyoma virus readily integrates into mouse cells, unlike previous studies in rat cells. The large T protein is key to this integration, even without viral replication.
Area of Science:
- Virology
- Molecular Biology
- Genetics
Background:
- Mouse polyomavirus naturally infects mice.
- Previous studies on polyomavirus integration focused on rat cells, not its natural host.
Purpose of the Study:
- To investigate polyomavirus integration in mouse cells.
- To determine the role of the large T protein in polyomavirus integration.
Main Methods:
- Cotransfection of mouse cell lines with the polyomavirus genome and selectable markers (tk or neo genes).
- Analysis of TK+ or G418R clones to assess integration efficiency.
- Investigating the necessity and sufficiency of the large T protein for integration.
Main Results:
- Polyomavirus presence reduced the number of selectable clones by up to 50-fold.
- The large T protein was necessary and sufficient for this reduction.
- All analyzed clones (33/33) surviving cotransfection contained integrated polyomavirus DNA.
- Over 50% of these clones showed integration of the entire polyomavirus genome.
- Integration occurred independently of polyomavirus replication.
Conclusions:
- Polyomavirus DNA integrates readily into mouse cellular DNA.
- The large T protein plays a crucial role in facilitating polyomavirus integration in its natural host.
