Abstract
Genetic studies in yeast have indicated a role of the RAD50 and MRE11 genes in homologous recombination, telomere length maintenance, and DNA repair processes. Here, we purify from nuclear extract of Raji cells a complex consisting of human Rad50, Mre11, and another protein factor with a size of about 95 kDa (p95), which is likely to be Nibrin, the protein encoded by the gene mutated in Nijmegen breakage syndrome. We show that the Rad50-Mre11-p95 complex possesses manganese-dependent single-stranded DNA endonuclease and 3' to 5' exonuclease activities. These nuclease activities are likely to be important for recombination, repair, and genomic stability.
Publication types
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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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Cell Cycle Proteins / metabolism*
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DNA Repair Enzymes*
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DNA Repair*
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DNA, Single-Stranded / metabolism
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DNA-Binding Proteins / metabolism*
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Endodeoxyribonucleases / metabolism
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Exodeoxyribonucleases / metabolism
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Humans
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MRE11 Homologue Protein
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Macromolecular Substances
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Molecular Weight
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Nuclear Proteins*
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Tumor Cells, Cultured
Substances
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Cell Cycle Proteins
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DNA, Single-Stranded
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DNA-Binding Proteins
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MRE11 protein, human
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Macromolecular Substances
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NBN protein, human
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Nuclear Proteins
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Endodeoxyribonucleases
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Exodeoxyribonucleases
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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