title: Recql5 plays an important role in DNA replication and cell survival after camptothecin treatment.
abstract: Disruption of replication can lead to loss of genome integrity and increase of cancer susceptibility in mammals. Thus, a replication impediment constitutes a formidable challenge to these organisms. Recent studies indicate that homologous recombination (HR) plays an important role in suppressing genome instability and promoting cell survival after exposure to various replication inhibitors, including a topoisomerase I inhibitor, camptothecin (CPT). Here, we report that the deletion of RecQ helicase Recql5 in mouse ES cells and embryonic fibroblast (MEF) cells resulted in a significant increase in CPT sensitivity and a profound reduction in DNA replication after the treatment with CPT, but not other DNA-damaging agents. This CPT-induced cell death is replication dependent and occurs primarily after the cells had exited the first cell cycle after CPT treatment. Furthermore, we show that Recql5 functions nonredundantly with Rad51, a key factor for HR to protect mouse ES cells from CPT-induced cytotoxicity. These new findings strongly suggest that Recql5 plays an important role in maintaining active DNA replication to prevent the collapse of replication forks and the accumulation of DSBs in order to preserve genome integrity and to prevent cell death after replication stress as a result of topoisomerase I poisoning.
authors.affiliation: Department of Genetics, Case Comprehensive Cancer Center, University Hospitals of Cleveland and Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Yiduo
authors.initials: Y
authors.lastname: Hu
authors.forename: Xincheng
authors.initials: X
authors.lastname: Lu
authors.forename: Guangjin
authors.initials: G
authors.lastname: Zhou
authors.forename: Ellen L
authors.initials: EL
authors.lastname: Barnes
authors.forename: Guangbin
authors.initials: G
authors.lastname: Luo
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology; D002166:Camptothecin / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D004261:DNA Replication / Q000187:drug effects; D053595:Embryonic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D006801:Humans; D051379:Mice; D051135:Rad51 Recombinase / Q000378:metabolism; D053484:RecQ Helicases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D004791:Enzyme Inhibitors; D051135:Rad51 Recombinase; D053484:RecQ Helicases; C501069:Recql5 protein, mouse; D002166:Camptothecin