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Interaction of SV40 large T antigen with components of the nucleo/cytoskeleton
I Klawitz1, U Preuss, K H Scheidtmann
1Institute of Genetics, University of Bonn, Germany.
Abstract:
The SV40 large T antigen is a viral oncoprotein which performs multiple interactions with cellular factors to achieve a proliferative state required for viral replication as well as for transformation. The major targets in this scenario are members of the Rb family, pRb, p107, and p130, and tumor suppressor protein p53. These interactions of large T with Rb proteins and p53 are required but not sufficient for transformation. To search for unknown interaction partners of large T that might participate in its transforming activity we employed the yeast two-hybrid system. Screening a cDNA library from a large T-induced brain tumor cell line revealed a total of 86 positive clones representing 37 individual clones. Of these, four clones were selected for further analyses. Interestingly, the cDNA inserts of these clones coded for different components of the cytoskeleton, lamin C, laminin gamma1, thymosin beta4, and gelsolin. Complex formation between large T and these proteins was confirmed in vitro. Interaction of large T with these components might influence activities such as intracellular transport, signal transduction, adhesion, or migration.
Insights
The SV40 large T antigen interacts with cellular cytoskeleton proteins, including lamin C and gelsolin. These interactions may contribute to the virus's transforming activity and influence cell functions.
Area of Science:
- Oncology
- Virology
- Cell Biology
Background:
- The SV40 large T antigen (LT) is a viral oncoprotein crucial for viral replication and cell transformation.
- LT interacts with key cellular proteins like the Rb family (pRb, p107, p130) and p53, but these are insufficient for transformation.
- The search for additional LT interaction partners is vital to understand its oncogenic mechanisms.
Purpose of the Study:
- To identify novel cellular interaction partners of the SV40 large T antigen.
- To investigate potential roles of these new partners in the transforming activity of SV40 LT.
Main Methods:
- Yeast two-hybrid system screening of a cDNA library from an SV40 LT-induced brain tumor cell line.
- Selection and analysis of positive clones.
- In vitro confirmation of complex formation between SV40 LT and identified proteins.
Main Results:
- Screening identified 86 positive clones, representing 37 unique genes.
- Four clones were further analyzed, revealing interactions with cytoskeleton components: lamin C, laminin gamma1, thymosin beta4, and gelsolin.
- In vitro assays confirmed complex formation between SV40 LT and these cytoskeletal proteins.
Conclusions:
- SV40 large T antigen interacts with multiple cytoskeletal proteins.
- These interactions may mediate SV40 LT's transforming activity by influencing cellular processes like intracellular transport, adhesion, and migration.