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In Situ Monitoring of Transiently Formed Molecular Chaperone Assemblies in Bacteria, Yeast, and Human Cells
Published on: September 2, 2019
Molecular chaperone function of the SV40 large T antigen
1Department of Biological Sciences, University of Pittsburgh, Pennsylvania 15260, USA.
Developments in Biological Standardization
|October 17, 1998
Summary
Simian virus 40 large tumor antigen (T antigen) has a novel J-domain activity essential for cell transformation. This activity requires cooperation with T antigen's retinoblastoma protein binding site and potentially p53 for full oncogenic function.
Area of Science:
- Molecular Biology
- Virology
- Oncology
Background:
- Simian virus 40 large tumor antigen (T antigen) is a viral oncogene.
- T antigen transforms cells and induces tumors via multiple functions.
- These functions involve interactions with cellular tumor suppressors like p53 and retinoblastoma (Rb) family proteins.
Purpose of the Study:
- To characterize a novel transforming function of T antigen, termed "Activity X".
- To elucidate the biochemical nature and requirements of Activity X for T antigen-mediated cell transformation.
Main Methods:
- Biochemical assays to identify the domain responsible for Activity X.
- Genetic analysis to determine the functional relationship between Activity X and other T antigen motifs.
Main Results:
- Activity X is a J-domain, indicating T antigen functions as a DnaJ molecular chaperone.
- Activity X must act in cis with the T antigen Rb-family binding motif for transformation.
- Activity X also requires cooperation with the carboxy-terminal half of T antigen, potentially involving p53.
Conclusions:
- SV40 T antigen possesses a J-domain chaperone activity crucial for oncogenesis.
- Cooperative action between the J-domain, Rb-binding motif, and p53-interacting region is necessary for T antigen's transforming potential.
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