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An amino-terminal fragment of SV40 T antigen transforms REF52 cells
1Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder 80302.
Abstract:
An SV40 mutant, T147D, encodes only the amino-terminal 147 amino acids of large T antigen and does not make small t antigen. We show here that a retrovirus which expresses this mutant T antigen transforms rat REF52 cells as efficiently as a retrovirus that expresses both the wild-type large and small T antigens. This cell line had previously been refractory to transformation by mutants that make short, amino-terminal fragments of T antigen.
Insights
A Simian virus 40 (SV40) mutant, T147D, efficiently transforms rat cells. This mutant, encoding only part of the large T antigen, demonstrates transformation capability comparable to wild-type SV40.
Area of Science:
- Virology
- Molecular Biology
- Cell Biology
Background:
- Simian virus 40 (SV40) large T antigen is crucial for viral replication and cellular transformation.
- Previous studies indicated that specific amino-terminal fragments of large T antigen could mediate transformation.
- The role of distinct large T antigen domains in cellular transformation requires further elucidation.
Purpose of the Study:
- To investigate the transforming potential of a specific SV40 large T antigen mutant (T147D).
- To compare the transformation efficiency of T147D with wild-type SV40 in rat REF52 cells.
- To determine if T147D can transform cell lines previously refractory to other SV40 mutants.
Main Methods:
- Construction and expression of a retrovirus encoding the SV40 T147D mutant.
- Generation of a retrovirus expressing wild-type SV40 large T and small t antigens.
- Transformation assays using rat REF52 cells with the engineered retroviruses.
Main Results:
- The SV40 T147D mutant, expressing only the N-terminal 147 amino acids of large T antigen, efficiently transformed rat REF52 cells.
- Transformation efficiency of T147D was comparable to wild-type SV40, which expresses both large T and small t antigens.
- Rat REF52 cells, previously resistant to transformation by other short T antigen mutants, were transformed by T147D.
Conclusions:
- The amino-terminal 147 amino acids of SV40 large T antigen are sufficient for efficient cellular transformation.
- The small t antigen is not essential for SV40-mediated transformation of REF52 cells.
- SV40 T147D represents a potent transforming agent, highlighting the importance of the N-terminus of large T antigen.