The CMG Helicase Bypasses DNA-Protein Cross-Links to Facilitate Their Repair

Justin L Sparks, Gheorghe Chistol, Alan O. Gao, Markus Räschle, Nicolai B. Larsen, Matthias Mann, Julien P. Duxin, Johannes C. Walter*

*Corresponding author af dette arbejde

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

129 Citationer (Scopus)
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Abstract

Covalent DNA-protein cross-links (DPCs) impede replication fork progression and threaten genome integrity. Using Xenopus egg extracts, we previously showed that replication fork collision with DPCs causes their proteolysis, followed by translesion DNA synthesis. We show here that when DPC proteolysis is blocked, the replicative DNA helicase CMG (CDC45, MCM2-7, GINS), which travels on the leading strand template, bypasses an intact leading strand DPC. Single-molecule imaging reveals that GINS does not dissociate from CMG during bypass and that CMG slows dramatically after bypass, likely due to uncoupling from the stalled leading strand. The DNA helicase RTEL1 facilitates bypass, apparently by generating single-stranded DNA beyond the DPC. The absence of RTEL1 impairs DPC proteolysis, suggesting that CMG must bypass the DPC to enable proteolysis. Our results suggest a mechanism that prevents inadvertent CMG destruction by DPC proteases, and they reveal CMG's remarkable capacity to overcome obstacles on its translocation strand.

OriginalsprogEngelsk
TidsskriftCell
Vol/bind176
Udgave nummer1-2
Sider (fra-til)167-181.e21
ISSN0092-8674
DOI
StatusUdgivet - 2019

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