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"Reconstitution of 5'-directed human mismatch repair in a purified system." |
Zhang Y, Yuan F, Presnell SR, Tian K, Gao Y, Tomkinson AE, Gu L, Li GM |
Published Sept. 9, 2005 in Cell volume 122 .
Pubmed ID: 16143102
Abstract:
| This paper reports reconstitution of 5'-nick-directed mismatch repair using purified human proteins. The reconstituted system includes MutSalpha or MutSbeta, MutLalpha, RPA, EXO1, HMGB1, PCNA, RFC, polymerase delta, and ligase I. In this system, MutSbeta plays a limited role in repair of base-base mismatches, but it processes insertion/deletion mispairs much more efficiently than MutSalpha, which efficiently corrects both types of heteroduplexes. MutLalpha reduces the processivity of EXO1 and terminates EXO1-catalyzed excision upon mismatch removal. In the absence of MutLalpha, mismatch-provoked excision by EXO1 occurs extensively. RPA and HMGB1 play similar but complementary roles in stimulating MutSalpha-activated, EXO1-catalyzed excision in the presence of a mismatch, but RPA has a distinct role in facilitating MutLalpha-mediated excision termination past mismatch. Evidence is provided that efficient repair of a single mismatch requires multiple molecules of MutSalpha-MutLalpha complex. These data suggest a model for human mismatch repair involving coordinated initiation and termination of mismatch-provoked excision. |
This publication refers to following REPAIRtoire entries:
| Proteins |
Last modification of this entry: Oct. 6, 2010
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