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Updated: Jun 27, 2026
08:38
Genome-wide Protein-protein Interaction Screening by Protein-fragment Complementation Assay (PCA) in Living Cells
Published on: March 3, 2015
The p21 and PCNA partnership: a new twist for an old plot
Carol Prives1, Vanesa Gottifredi
1Department of Biological Sciences, Columbia University, New York, New York, USA.
Cell Cycle (Georgetown, Tex.)
|December 11, 2008
Summary
The protein p21 acts as a negative regulator of translesion DNA synthesis (TLS) polymerases, preventing DNA damage and mutagenesis. Its degradation after UV irradiation allows for efficient DNA repair and cell survival.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Error-prone DNA polymerases are crucial for translesion DNA synthesis (TLS), enabling DNA repair past lesions.
- TLS polymerases can be mutagenic, necessitating regulation to prevent errors on undamaged DNA.
- The cyclin-dependent kinase inhibitor p21 has emerged as a key regulator in the DNA damage response.
Purpose of the Study:
- To investigate the role of p21 as a negative regulator of TLS polymerases.
- To elucidate how p21 modulates TLS activity and its interaction with PCNA.
- To understand p21's function in balancing mutagenesis and cell survival.
Main Methods:
- Investigated the interaction between p21, PCNA, and TLS polymerase eta.
- Assessed the effect of p21 on PCNA ubiquitination status.
- Analyzed p21's role in regulating TLS efficiency and accuracy.
Main Results:
- p21 inhibits the recruitment of TLS polymerases to undamaged DNA, preventing mutagenesis.
- Both CDK and PCNA binding domains of p21 are critical for modulating TLS.
- p21 reduces TLS efficiency but enhances its accuracy.
- p21 degradation after UV irradiation facilitates TLS polymerases' role in DNA repair.
Conclusions:
- p21 acts as a crucial negative regulator of TLS, maintaining genomic stability.
- p21's modulation of TLS is essential for balancing mutagenesis and cell survival, particularly after DNA damage.
- p21 plays a significant role in the DNA damage response in higher eukaryotes.
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