Stability of the human polymerase δ holoenzyme and its implications in lagging strand DNA synthesis

Mark Hedglin, Binod Pandey, Stephen J. Benkovic

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

In eukaryotes, DNA polymerase δ (pol δ) is responsible for replicating the lagging strand template and anchors to the proliferating cell nuclear antigen (PCNA) sliding clamp to form a holoenzyme. The stability of this complex is integral to every aspect of lagging strand replication. Most of our understanding comes from Saccharomyces cerevisae where the extreme stability of the pol δ holoenzyme ensures that every nucleobase within an Okazaki fragment is faithfully duplicated before dissociation but also necessitates an active displacement mechanism for polymerase recycling and exchange. However, the stability of the human pol δ holoenzyme is unknown. We designed unique kinetic assays to analyze the processivity and stability of the pol δ holoenzyme. Surprisingly, the results indicate that human pol δ maintains a loose association with PCNA while replicating DNA. Such behavior has profound implications on Okazaki fragment synthesis in humans as it limits the processivity of pol δ on undamaged DNA and promotes the rapid dissociation of pol δ from PCNA on stalling at a DNA lesion.

Original languageEnglish (US)
Pages (from-to)E1777-E1786
JournalProceedings of the National Academy of Sciences of the United States of America
Volume113
Issue number13
DOIs
StatePublished - Mar 29 2016

All Science Journal Classification (ASJC) codes

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