Related Experiment Videos
Inhibition of DNA replication factor RPA by p53
A Dutta1, J M Ruppert, J C Aster
1Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
Abstract:
The tumour suppressor p53 specifically interferes with the onset of S phase. The mechanism of the growth suppression action of the protein is unclear, though recent evidence points to transcriptional activation and repression functions of the protein. A competing hypothesis suggests that p53 interacts with the DNA replication apparatus and directly interferes with DNA replication. The major evidence for this hypothesis is that p53 interacts with the simian virus 40 (SV40)-encoded protein T antigen and interferes with the ability of T antigen to unwind the SV40 origin of DNA replication, and recruit DNA polymerase alpha to the replication initiation complex. Here we report that p53 physically interacts with and inhibits the function of a cellular DNA replication factor, the single-stranded DNA-binding protein complex RPA.
Insights
The tumor suppressor p53 protein directly inhibits DNA replication by interacting with the replication factor RPA (Replication Protein A). This finding clarifies p53
Area of Science:
- Molecular Biology
- Cell Cycle Regulation
- Tumor Suppression
Background:
- The tumor suppressor p53 protein plays a critical role in preventing cancer by inhibiting cell growth, particularly at the start of S phase.
- The precise mechanism by which p53 suppresses growth is not fully understood, with current hypotheses including transcriptional regulation or direct interference with DNA replication.
- Previous studies showed p53 interacts with viral proteins like SV40 T antigen, affecting DNA replication initiation.
Purpose of the Study:
- To investigate the direct interaction of p53 with cellular DNA replication machinery.
- To elucidate the role of p53 in regulating DNA replication processes.
Main Methods:
- Investigated the physical interaction between p53 and the single-stranded DNA-binding protein complex RPA (Replication Protein A).
- Assessed the functional impact of p53 on RPA activity in DNA replication.
Main Results:
- Demonstrated that p53 physically interacts with the RPA complex.
- Showed that p53 inhibits the function of RPA, a key cellular DNA replication factor.
Conclusions:
- p53 directly interferes with cellular DNA replication by inhibiting RPA function.
- This interaction provides a direct mechanism for p53's growth-suppressive activity during the S phase.