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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1999-3-18
pubmed:abstractText
Mismatch repair (MMR) is initiated when a heterodimer of hMSH2*hMSH6 or hMSH2*hMSH3 binds to mismatches. Here we perform functional analyses of these human protein complexes in yeast. We use a sensitive genetic system wherein the rate of single-base deletions in a homopolymeric run in the LYS2 gene is 10 000-fold higher in an msh2 mutant than in a wild-type strain. Expression of the human proteins alone or in combination does not reduce the mutation rate of the msh2 strain, and expression of the individual human proteins does not increase the low mutation rate of a wild-type strain. However, co-expression of hMSH2 and hMSH6 in wild-type yeast increases the mutation rate 4000-fold, while co-expression of hMSH2 and hMSH3 elevates the rate 5-fold. Analysis of cell extracts indicates that the proteins are expressed and bind to mismatched DNA. The results suggest that hMutSalpha and hMutSbeta complexes form, bind to and prevent correction of replication slippage errors in yeast. Expression of hMSH6 with hMSH2 containing a proline substituted for a conserved Arg524 eliminates the mutator effect and reduces mismatch binding. The analogous mutation in humans is associated with microsatellite instability, defective MMR and cancer, illustrating the utility of the yeast system for studying human disease alleles.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0305-1048
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
736-42
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Functional analysis of human MutSalpha and MutSbeta complexes in yeast.
pubmed:affiliation
Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, PO Box 12233,Research Triangle Park, NC 27709, USA.
pubmed:publicationType
Journal Article