Abstract
Artemis is a recently identified factor involved in V(D)J recombination and nonhomologous end joining (NHEJ) of DNA double-strand break (DSB) repair. Here, we performed targeted disruption of the Artemis gene (ARTEMIS) in the human pre-B cell line Nalm-6. Unexpectedly, we found that cells lacking Artemis exhibit increased sensitivity to low doses, but not high doses, of ionizing radiation. We also show that ARTEMIS-deficient cells are hypersensitive to the topoisomerase II inhibitor etoposide, but to a much lesser extent than cells lacking DNA ligase IV, a critical component of NHEJ. Unlike DNA ligase IV-deficient cells, ARTEMIS-deficient cells were not hypersensitive to ICRF-193, a topoisomerase II inhibitor that does not stabilize topoisomerase II-DNA cleavable complexes. Collectively, our results suggest that Artemis only partially participates in the NHEJ pathway to repair DSBs in human somatic cells.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Blotting, Southern
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Blotting, Western
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Cells, Cultured / drug effects
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Cells, Cultured / radiation effects
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Colony-Forming Units Assay
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DNA Breaks, Double-Stranded / drug effects*
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DNA Breaks, Double-Stranded / radiation effects*
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DNA Primers / chemistry
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DNA Repair / drug effects*
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DNA Repair / radiation effects*
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DNA Topoisomerases, Type II / metabolism
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DNA-Binding Proteins
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Diketopiperazines
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Dose-Response Relationship, Radiation
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Endonucleases
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Enzyme Inhibitors / pharmacology*
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Etoposide / pharmacology
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Flow Cytometry
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Humans
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Nuclear Proteins / physiology*
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Piperazines / pharmacology
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Precursor Cells, B-Lymphoid / drug effects
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Precursor Cells, B-Lymphoid / metabolism
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Precursor Cells, B-Lymphoid / radiation effects
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Radiation Tolerance
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Radiation, Ionizing
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Recombination, Genetic / genetics
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Reverse Transcriptase Polymerase Chain Reaction
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Topoisomerase II Inhibitors
Substances
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DNA Primers
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DNA-Binding Proteins
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Diketopiperazines
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Enzyme Inhibitors
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Nuclear Proteins
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Piperazines
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RNA, Messenger
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Topoisomerase II Inhibitors
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4,4'-(1,2-dimethyl-1,2-ethanediyl)bis-2,6-piperazinedione
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Etoposide
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DCLRE1C protein, human
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Endonucleases
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DNA Topoisomerases, Type II