Human RECQ5β helicase promotes strand exchange on synthetic DNA structures resembling a stalled replication fork

Radhakrishnan Kanagaraj, Nurten Saydam, Patrick L. Garcia, Lu Zheng, Pavel Janscak

Research output: Contribution to journalArticlepeer-review

101 Scopus citations

Abstract

The role of the human RECQ5β helicase in the maintenance of genomic stability remains elusive. Here we show that RECQ5β promotes strand exchange between arms of synthetic forked DNA structures resembling a stalled replication fork in a reaction dependent on ATP hydrolysis. BLM and WRN can also promote strand exchange on these structures. However, in the presence of human replication protein A (hRPA), the action of these RecQ-type helicases is strongly biased towards unwinding of the parental duplex, an effect not seen with RECQ5β. A domain within the non-conserved portion of RECQ5β is identified as being important for its ability to unwind the lagging-strand arm and to promote strand exchange on hRPA-coated forked structures. We also show that RECQ5β associates with DNA replication factories in S phase nuclei and persists at the sites of stalled replication forks after exposure of cells to UV irradiation. Moreover, RECQ5β is found to physically interact with the polymerase processivity factor proliferating cell nuclear antigen in vitro and in vivo. Collectively, these findings suggest that RECQ5β may promote regression of stalled replication forks to facilitate the bypass of replication-blocking lesions by template-switching. Loss of such activity could explain the elevated level of mitotic crossovers observed in RECQ5β-deficient cells.

Original languageEnglish (US)
Pages (from-to)5217-5231
Number of pages15
JournalNucleic acids research
Volume34
Issue number18
DOIs
StatePublished - Oct 15 2006

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