Human DNA polymerase α has a strong mutagenic potential at the initial steps of DNA synthesis.

Nucleic Acids Res

Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA.

Published: November 2022

DNA polymerase α (Polα) is essential for DNA replication initiation and makes a notable contribution to genome mutagenesis. The activity and fidelity of Polα during the early steps of DNA replication have not been well studied. Here we show that at the beginning of DNA synthesis, when extending the RNA primer received from primase, Polα is more mutagenic than during the later DNA elongation steps. Kinetic and binding studies revealed substantially higher activity and affinity to the template:primer when Polα interacts with ribonucleotides of a chimeric RNA-DNA primer. Polα activity greatly varies during first six steps of DNA synthesis, and the bias in the rates of correct and incorrect dNTP incorporation leads to impaired fidelity, especially upon the second step of RNA primer extension. Furthermore, increased activity and stability of Polα/template:primer complexes containing RNA-DNA primers result in higher efficiency of mismatch extension.

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Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9757036PMC
http://dx.doi.org/10.1093/nar/gkac1101DOI Listing

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