Abstract
We show that hypomorphic mutations in hMRE11, but not in ATM, are present in certain individuals with an ataxia-telangiectasia-like disorder (ATLD). The cellular features resulting from these hMRE11 mutations are similar to those seen in A-T as well as NBS and include hypersensitivity to ionizing radiation, radioresistant DNA synthesis, and abrogation of ATM-dependent events, such as the activation of Jun kinase following exposure to gamma irradiation. Although the mutant hMre11 proteins retain some ability to interact with hRad50 and Nbs1, formation of ionizing radiation-induced hMre11 and Nbs1 foci was absent in hMRE11 mutant cells. These data demonstrate that ATM and the hMre11/hRad50/Nbs1 protein complex act in the same DNA damage response pathway and link hMre11 to the complex pathology of A-T.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Acid Anhydride Hydrolases
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Ataxia Telangiectasia / genetics*
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Ataxia Telangiectasia / metabolism
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Ataxia Telangiectasia / pathology
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism
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Cell Line
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DNA Damage / genetics
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DNA Mutational Analysis
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DNA Repair / genetics*
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DNA Repair Enzymes*
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DNA-Binding Proteins / genetics*
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DNA-Binding Proteins / metabolism
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Fibroblasts / metabolism
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Fibroblasts / pathology
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Fibroblasts / radiation effects
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Gamma Rays
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Humans
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MRE11 Homologue Protein
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Mutation, Missense / genetics
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Nuclear Proteins*
Substances
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Cell Cycle Proteins
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DNA-Binding Proteins
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MRE11 protein, human
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NBN protein, human
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Nuclear Proteins
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MRE11 Homologue Protein
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Acid Anhydride Hydrolases
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RAD50 protein, human
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DNA Repair Enzymes