Abstract
Mismatch-provoked excision directed by a strand break located 3' or 5' to the mispair has been reconstituted using purified human proteins. While MutSalpha, EXOI, and RPA are sufficient to support hydrolysis directed by a 5' strand break, 3' directed excision also requires MutLalpha, PCNA, and RFC. EXOI interacts with PCNA. RFC and PCNA suppress EXOI-mediated 5' to 3' hydrolysis when the nick that directs excision is located 3' to the mispair and activate 3' to 5' excision, which is dependent on loaded PCNA and apparently mediated by a cryptic EXOI 3' to 5' hydrolytic function. By contrast, RFC and PCNA have only a limited effect on 5' to 3' excision directed by a 5' strand break.
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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Base Pair Mismatch / genetics*
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Carrier Proteins / genetics
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Carrier Proteins / metabolism
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Cell-Free System / metabolism
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DNA / genetics
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DNA / metabolism*
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DNA Damage / genetics*
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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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Exodeoxyribonucleases / genetics
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Exodeoxyribonucleases / metabolism
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HeLa Cells
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Humans
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Hydrolysis
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MutL Proteins
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Proliferating Cell Nuclear Antigen / genetics
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Proliferating Cell Nuclear Antigen / metabolism
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Proteins / genetics
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Proteins / metabolism
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Replication Protein A
Substances
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Carrier Proteins
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DNA-Binding Proteins
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MLH3 protein, human
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Proliferating Cell Nuclear Antigen
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Proteins
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RPA1 protein, human
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Replication Protein A
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DNA
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EXO1 protein, human
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Exodeoxyribonucleases
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exodeoxyribonuclease I
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MutL Proteins
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DNA Repair Enzymes