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PEBP2--a modulator of polyoma DNA replication
S E Rutberg1, L R Dolan, Z Ronai
1Molecular Carcinogenesis Program, American Health Foundation, Valhalla, NY 10595.
Abstract:
Previously, we have shown that integrated copies of polyoma DNA can be induced to replicate in rat fibroblasts (H3 cells) exposed to a DNA-damaging agent. In the current study, we demonstrate that UV-irradiation of mouse fibroblasts (WOP cells), transiently transfected with polyoma DNA, results in repression of polyoma replication. Cotransfection of oligomers representing wild-type but not mutated forms of the PEBP2 target sequence restored levels of viral replication indicating a role of PEBP2 binding proteins in mediating this effect. DNA-binding assays revealed that a different subset of complexes was formed with the PEBP2 target sequence when nuclear proteins from sham and UV-irradiated WOP and H3 cells were compared, suggesting that the activities of PEBP2 binding proteins are differentially regulated upon UV-irradiation in these two cell types. The ability of PEBP2 to modulate polyoma replication following UV-irradiation in WOP cells suggests a potential role of PEBP2 proteins in the cellular response to DNA damage.
Insights
UV irradiation represses polyoma DNA replication in mouse cells, unlike in rat cells. This effect is mediated by PEBP2 binding proteins, suggesting their role in DNA damage response.
Area of Science:
- Molecular Biology
- Virology
- Cellular Biology
Background:
- Integrated polyoma DNA replication can be induced by DNA-damaging agents in rat fibroblasts (H3 cells).
- The cellular response to DNA damage involves complex regulatory mechanisms affecting viral replication.
Purpose of the Study:
- To investigate the effect of UV irradiation on polyoma DNA replication in mouse fibroblasts (WOP cells).
- To identify the role of PEBP2 binding proteins in mediating UV-induced changes in polyoma replication.
Main Methods:
- Transient transfection of WOP cells with polyoma DNA.
- UV irradiation of transfected cells.
- Cotransfection with wild-type and mutated PEBP2 target sequences.
- DNA-binding assays to compare nuclear protein complexes.
Main Results:
- UV irradiation repressed polyoma replication in WOP cells.
- Restoration of polyoma replication was observed with wild-type, but not mutated, PEBP2 target sequences.
- Differential formation of PEBP2 binding complexes in UV-irradiated WOP and H3 cells was detected.
Conclusions:
- PEBP2 binding proteins play a role in mediating the repression of polyoma replication following UV irradiation in WOP cells.
- The activity of PEBP2 binding proteins is differentially regulated by UV irradiation in different cell types.
- PEBP2 proteins may be involved in the cellular response to DNA damage.