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Binding and suppression of the Myc transcriptional activation domain by p107
1Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, NY 10032.
Abstract:
An amino-terminal transactivation domain is required for Myc to function as a transcription factor controlling cell proliferation, differentiation, and apoptosis. A complementary DNA expression library was screened with a Myc fusion protein to identify proteins interacting with this domain, and a clone encoding the Rb-related p107 protein was isolated. The p107 protein was shown to associate with Myc in vivo and to suppress the activity of the Myc transactivation domain. However, mutant forms of Myc from Burkitt lymphoma cells, which contain sequence alterations in the transactivation domain, were resistant to p107-mediated suppression. Thus, disruption of a regulatory interaction between Myc and p107 may be important in tumorigenesis.
Insights
Researchers identified the p107 protein interacting with the Myc transactivation domain, a key factor in cell growth. Disruption of this interaction may contribute to cancer development, particularly in Burkitt lymphoma.
Area of Science:
- Molecular Biology
- Oncology
- Cell Biology
Background:
- The Myc protein is a crucial transcription factor regulating cell proliferation, differentiation, and apoptosis.
- Its function relies on an amino-terminal transactivation domain.
- Dysregulation of Myc is implicated in various cancers.
Purpose of the Study:
- To identify proteins that interact with the Myc transactivation domain.
- To investigate the functional consequences of this interaction.
- To explore the role of this interaction in tumorigenesis.
Main Methods:
- Screening of a complementary DNA expression library using a Myc fusion protein.
- In vivo association studies to confirm protein interactions.
- Functional assays to assess the suppression of Myc transactivation activity by p107.
Main Results:
- Isolation of a clone encoding the Rb-related p107 protein.
- Demonstration of p107 associating with Myc in vivo.
- Evidence that p107 suppresses the activity of the Myc transactivation domain.
- Identification of mutant Myc forms from Burkitt lymphoma resistant to p107 suppression.
Conclusions:
- The p107 protein directly interacts with the Myc transactivation domain.
- This interaction negatively regulates Myc's transcriptional activity.
- Mutations in the Myc transactivation domain can confer resistance to p107-mediated suppression.
- Disruption of the Myc-p107 regulatory interaction is a potential mechanism in tumorigenesis, especially in Burkitt lymphoma.