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bioRxiv · 10.64898/2026.05.19.725978

Dissecting the role of PCNA and Pif1 in replication of individual DNA molecules by DNA polymerase δ.

Zaher, M. S.·Stith, C.·Mistry, A.·Poudel, P. B.·Antony, E.·Burgers, P. M.·Galletto, R.
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Abstract

PCNA loading and stabilization at primer-template junctions is crucial for processive DNA synthesis by replicative polymerases. It is also essential for strand displacement synthesis during Break Induced Replication (BIR). In this study, we employed a single molecule approach to directly visualize the role of PCNA, DNA polymerase {delta} and the Pif1 DNA helicase in these pathways. We first dissected the preferential loading of PCNA by RFC to 3-junctions of gaps, nicks and flapped substrates. Moreover, we found that Pol {delta} and Pif1 both stabilize loaded PCNA and reduce its diffusion coefficient along DNA. We further show that the interaction of PCNA with Pol {delta} is essential for gap-filling synthesis. On a 5-flapped substrate, we show that both Pol {delta} and Pif1 are required for strand displacement synthesis, while PCNA is not; although, it stimulates the process.

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Zaher, M. S., Stith, C., Mistry, A., Poudel, P. B., Antony, E., Burgers, P. M., Galletto, R.. 2026-05-21. Dissecting the role of PCNA and Pif1 in replication of individual DNA molecules by DNA polymerase δ.. https://doi.org/10.64898/2026.05.19.725978

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