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Lesion bypass DNA polymerases replicate across non-DNA segments
Ayelet Maor-Shoshani1, Vered Ben-Ari, Zvi Livneh
1Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
Summary
Specialized DNA polymerases can replicate DNA across non-DNA material. DNA polymerase V in E. coli bypasses hydrocarbon chains, demonstrating robust translesion synthesis essential for genome stability.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- DNA replication requires robustness to overcome DNA damage.
- Translesion synthesis (TLS) by Y-family polymerases is a key mechanism for bypassing DNA lesions.
- Understanding the limits of TLS is crucial for genome stability.
Purpose of the Study:
- To investigate the ability of DNA polymerase V to replicate across foreign non-DNA inserts.
- To elucidate the mechanisms by which DNA polymerase V bypasses hydrocarbon chains.
- To assess the robustness of the translesion replication apparatus.
Main Methods:
- Plasmid replication experiments in Escherichia coli.
- Utilizing plasmids containing foreign non-DNA inserts (hydrocarbon chains).
- Characterization of DNA polymerase V activity and bypass mechanisms.
Main Results:
- Escherichia coli DNA polymerase V replicated plasmids across hydrocarbon chains of 3 or 12 methylene residues.
- Two bypass mechanisms were observed: deletion of the insert via polymerase hopping and synthesis through the insert.
- DNA synthesis occurred opposite hydrocarbon chains lacking DNA features, incorporating nucleotides.
Conclusions:
- DNA polymerase V exhibits remarkable ability to synthesize DNA across non-DNA templates, demonstrating extreme robustness.
- Translesion synthesis is capable of bypassing segments lacking fundamental DNA characteristics.
- This bypass ability contributes significantly to maintaining genome stability.