The RecQ DNA Helicases in DNA Repair

Abstract

The RecQ helicases are conserved from bacteria to humans and play a critical role in genome stability. In humans, loss of RecQ gene function is associated with cancer predisposition and/or premature aging. Recent data have shown that the RecQ helicases function during two distinct steps during DNA repair; DNA end resection and resolution of double Holliday junctions (dHJs). RecQ functions in these different processing steps has important implications for its role in repair of double-strand breaks (DSBs) that occur during DNA replication, meiosis and at specific genomic loci such as telomeres.

DNA2 Cooperates with the WRN and BLM RecQ Helicases to Mediate Long-range DNA End Resection in Human Cells

“…However, it remains a matter of debate which DNA helicase mediates DNA2-catalyzed resection in mammalian cells. Mammals pos-sess five RecQ homologues: RECQ1, BLM, WRN, RECQ4, and RECQ5 (20). Biochemical studies have shown that human DNA2 can act in conjunction with the BLM helicase and RPA to mediate 5Ј-3Ј resection of DNA ends in vitro (17).…”

Synergic and Opposing Activities of Thermophilic RecQ-like Helicase and Topoisomerase 3 Proteins in Holliday Junction Processing and Replication Fork Stabilization

“…These enzymes are involved in DNA replication, recombination, repair, and chromosome segregation, and their malfunctioning may cause genome instability, premature aging, infertility, and cancer (for recent reviews, see Refs. [1][2][3][4][5]. At the biochemical level, RecQ-Top3 enzymes induce coordinate DNA topoisomerase, ATPase, DNA unwinding, and DNA annealing and act on particular DNA structures to modify their topological linkages.…”

The MCM and RecQ Helicase Families: Ancient Roles in DNA Replication and Genomic Stability Lead to Distinct Roles in Human Disease

“…There is conservation of RecQ proteins from bacteria to humans. Whereas bacteria have one RecQ helicase, humans have evolved at least five different proteins [2]. The RecQ members belong to the helicase Superfamily II, and as such have the characteristic Rec fold [1].…”

“…The WRN and BLM proteins as well as other members of the RecQ family are characterized by this feature [8]. Both WRN and BLM are involved in DNA repair and a role for WRN in telomere homeostasis in humans is well established [2,9]. MCM2-7 proteins, along with cofactors, are thought to function as the eukaryotic replicative helicase [10].…”