Archaeal replicative primases can perform translesion DNA synthesis

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• DNA replication requires specialized polymerases for translesion synthesis (TLS) to bypass DNA damage.
• Most archaea lack canonical Y-family TLS polymerases found in prokaryotes and eukaryotes.
• Replicative polymerases often stall at DNA lesions, necessitating damage tolerance mechanisms.

Purpose of the Study:

• To investigate the potential TLS activity of archaeal replicative primases (Pri S).
• To determine if archaeal Pri S can bypass common DNA lesions, including oxidative damage and deoxyuracils.
• To elucidate the role of Pri S in replication restart and damage tolerance at stalled replication forks.

Main Methods:

• Biochemical assays to assess the DNA polymerase and TLS activity of archaeal Pri S.
• In vitro replication assays using DNA templates containing specific oxidative lesions and deoxyuracils.
• Analysis of replication bypass efficiency in the presence of stalled replicase complexes.

Main Results:

• Archaeal Pri S exhibits TLS proficiency, bypassing oxidative DNA lesions like 8-Oxo-2'-deoxyguanosines.
• Pri S effectively bypasses UV-induced DNA damage, including cyclobutane pyrimidine dimers.
• Pri S efficiently replicates past deoxyuracils, even when replicases are stalled, providing a novel bypass mechanism.

Conclusions:

• Archaeal replicative primases (Pri S) possess significant translesion DNA synthesis capabilities.
• Pri S functions as a DNA damage tolerance factor, bypassing lesions that stall canonical replicases.
• This finding expands the known functions of replicative primases and highlights a unique archaeal DNA repair pathway.