DDK Has a Primary Role in Processing Stalled Replication Forks to Initiate Downstream Checkpoint Signaling

Autor: Nanda Kumar Sasi, Flavie Coquel, Yea-Lih Lin, Jeffrey P MacKeigan, Philippe Pasero, Michael Weinreich
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Neoplasia: An International Journal for Oncology Research, Vol 20, Iss 10, Pp 985-995 (2018)
Druh dokumentu: article
ISSN: 1476-5586
DOI: 10.1016/j.neo.2018.08.001
Popis: Summary: CDC7-DBF4 kinase (DDK) initiates DNA replication in eukaryotes by activating the replicative MCM helicase. DDK has diverse and apparently conflicting roles in the replication checkpoint response in various organisms, but the underlying mechanisms are far from settled. We show that human DDK promotes limited resection of newly synthesized DNA at stalled replication forks or sites of DNA damage to initiate replication checkpoint signaling. DDK is also required for efficient fork restart and G2/M cell cycle arrest. DDK exhibits genetic interactions with the ssDNA exonuclease EXO1 and phosphorylates EXO1 in vitro. EXO1 is also required for nascent strand degradation following exposure to HU, so DDK might regulate EXO1 directly. Lastly, sublethal DDK inhibition causes various mitotic abnormalities, which is consistent with a checkpoint deficiency. In summary, DDK has a primary and previously undescribed role in the replication checkpoint to promote ssDNA accumulation at stalled forks, which is required to initiate a robust checkpoint response and cell cycle arrest to maintain genome integrity.
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