Related Experiment Videos
Eukaryotic translesion synthesis DNA polymerases: specificity of structure and function
Satya Prakash1, Robert E Johnson, Louise Prakash
1Sealy Center for Molecular Science, University of Texas Medical Branch, Galveston, Texas 77555-1061, USA. s.prakash@utmb.edu
Annual Review of Biochemistry
|June 15, 2005
Summary
Eukaryotic translesion synthesis (TLS) polymerases exhibit specific DNA lesion bypass properties despite structural similarities. Protein ubiquitination and scaffold proteins like PCNA are crucial for polymerase access and exchange at DNA damage sites.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Translesion synthesis (TLS) is a DNA repair mechanism utilizing specialized polymerases to bypass DNA lesions.
- Y-family polymerases (eta, iota, kappa, Rev1) and B-family polymerase zeta play critical roles in eukaryotic TLS.
- Understanding TLS polymerase function is vital for comprehending DNA damage tolerance and mutagenesis.
Purpose of the Study:
- To review and evaluate the fidelity, mismatch extension, and lesion bypass efficiencies of eukaryotic TLS polymerases.
- To correlate the structural features of TLS polymerases with their functional specificities in DNA lesion bypass.
- To elucidate the roles of PCNA and protein ubiquitination in facilitating TLS polymerase access and function.
Main Methods:
- Comparative analysis of structural and functional data for Y-family polymerases (eta, iota, kappa, Rev1) and Pol zeta.
- Examination of lesion bypass efficiencies and fidelity across various DNA lesions.
- Review of the literature on the involvement of PCNA and Rad6-Rad18-dependent ubiquitination in TLS.
Main Results:
- Y-family polymerases, despite structural similarities, display distinct lesion bypass specificities.
- Functional divergence in lesion bypass relates to specific structural differences among Y-family polymerases.
- Pol zeta is specialized for extending primer termini opposite DNA lesions, contributing to both mutagenic and error-free bypass.
- PCNA acts as a scaffold for TLS polymerase recruitment, and ubiquitination regulates polymerase exchange.
Conclusions:
- TLS polymerases exhibit specialized roles in DNA damage tolerance, dictated by their unique structural and functional properties.
- Structural variations among Y-family polymerases underpin their diverse lesion bypass capabilities.
- Coordinated action of TLS polymerases, PCNA, and ubiquitination machinery ensures efficient and regulated DNA repair at stalled replication forks.