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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
11
|
| pubmed:dateCreated |
1997-3-31
|
| pubmed:abstractText |
Human cell extracts perform an aberrant form of DNA synthesis on methylated plasmids [1], which represents processing of O6-methylguanine (O6-meG). Here, we show that extracts of colorectal carcinoma cells with defects in the mismatch repair proteins that normally correct replication errors do not carry out this synthesis. hMSH2-defective LoVo cell extracts (hMSH for human MutS homologue) performed O6-meG-dependent DNA synthesis only after the addition of the purified hMutS alpha mismatch recognition complex. Processing of O6-meG by mismatch correction requires PCNA and therefore probably DNA polymerase delta and/or epsilon. Mismatch repair-defective cells withstand O6-meG in their DNA [2], making them tolerant to methylating agents. Methylation-tolerant HeLaMR clones, with a mutator phenotype and a defect in either mismatch recognition or correction in vitro, also performed little O6-meG-dependent DNA synthesis. Assays of pairwise combinations of tolerant and colorectal carcinoma cell extracts identified hMLH1 as the missing mismatch repair function in a group of tolerant clones. The absence of processing by extracts of methylation-tolerant cells provides the first biochemical evidence that lethality of DNA O6-meG derives from its interaction with mismatch repair.
|
| pubmed:language |
eng
|
| pubmed:journal | |
| pubmed:citationSubset |
IM
|
| pubmed:chemical | |
| pubmed:status |
MEDLINE
|
| pubmed:month |
Nov
|
| pubmed:issn |
0960-9822
|
| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:day |
1
|
| pubmed:volume |
6
|
| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
1528-31
|
| pubmed:dateRevised |
2006-11-15
|
| pubmed:meshHeading | |
| pubmed:year |
1996
|
| pubmed:articleTitle |
Processing of O6-methylguanine by mismatch correction in human cell extracts.
|
| pubmed:affiliation |
Istituto Superiore di Sanita, Rome, Italy.
|
| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
|