Isolation of MutSβ from Human Cells and Comparison of the Mismatch Repair Specificities of MutSβ and MutSα

Genschel, Jochen; Littman, Susan J.; Drummond, James T.; Modrich, Paul

doi:10.1074/jbc.273.31.19895

Cited by 366 publications

(334 citation statements)

References 42 publications

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“…Although Vaco481 has a second mutation in hMSH3 and is, therefore, de®cient in hMutSb (a complex of hMSH2 and hMSH3 proteins), a defect in mismatch repair attributable to this mutation is not observable due to the presence of hMutSa (a complex between hMSH2 and hMSH6 proteins) in these extracts (see Table 1, 3', CA, heteroduplex). This result is reminiscent of previous results in which I/D mismatch repair activity of hMutSb was demonstrated to overlap that of hMutSa (Genschel et al, 1998). hMutSb may have distinct functions compared to hMutSa, but the nature of such functional di erences and the result of a lack of hMSH3 on this function are not presently known.…”

Section: Complementation Of Vaco481 Mismatch Repair By Hmutlasupporting

confidence: 83%

Somatic mutation of hPMS2 as a possible cause of sporadic human colon cancer with microsatellite instability

Xia

Littman

et al. 2000

Oncogene

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Inactivation of DNA-mismatch repair underlies the genesis of microsatellite unstable (MSI) colon cancers. hPMS2 is one of several genes encoding components of the DNA-mismatch repair complex, and germline hPMS2 mutations have been found in a few kindreds with hereditary nonpolyposis colorectal carcinoma (HNPCC), in whom hereditary MSI colon cancers develop. However, mice bearing null hPMS2 genes do not develop colon cancers and hPMS2 mutations in sporadic human colon cancers have not been described. Here we report that in Vaco481 colon cancer the hPMS2 gene is inactivated by somatic mutations of both hPMS2 alleles. The cell line derived from this tumor is functionally de®cient in DNA mismatch repair. This de®ciency can be biochemically complemented by addition of a puri®ed hMLH1-hPMS2 (hMutLa) complex. The hPMS2 de®cient Vaco481 cancer cell line demonstrates microsatellite instability, an elevated HPRT gene mutation rate, and resistance to the cytotoxicity of the alkylator MNNG. We conclude that somatic inactivation of hPMS2 can play a role in development of sporadic MSI colon cancer expressing the full range of cancer phenotypes associated with inactivation of the mismatch repair system. Oncogene (2000) 19, 2249 ± 2256.

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Section: Complementation Of Vaco481 Mismatch Repair By Hmutlasupporting

confidence: 83%

Somatic mutation of hPMS2 as a possible cause of sporadic human colon cancer with microsatellite instability

Xia

Littman

et al. 2000

Oncogene

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“…The overlapping roles of these heterodimeric complexes have been reported earlier (Acharya et al, 1996;Genschel et al, 1998) generally emphasising the role of MutSa predominantly for the recognition of base/base mispairs and small IDLs and MutSb for the recognition of larger (42 bp) IDLs (Acharya et al, 1996;Palombo et al, 1996). Our experiments support the functional redundancy but contradictory to the previous impression, in this study, the repair efficiency of MutSb was shown to exceed that of MutSa in the repair of dinucleotide loop structures.…”

Section: Discussioncontrasting

confidence: 56%

MutSβ exceeds MutSα in dinucleotide loop repair

et al. 2010

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BACKROUND: The target substrates of DNA mismatch recognising factors MutSa (MSH2 þ MSH6) and MutSb (MSH2 þ MSH3) have already been widely researched. However, the extent of their functional redundancy and clinical substance remains unclear. Mismatch repair (MMR)-deficient tumours are strongly associated with microsatellite instability (MSI) and the degree and type of MSI seem to be dependent on the MMR gene affected, and is linked to its substrate specificities. Deficiency in MSH2 and MSH6 is associated with both mononucleotide and dinucleotide repeat instability. Although no pathogenic MSH3 mutations have been reported, its deficiency is also suggested to cause low dinucleotide repeat instability. METHODS: To assess the substrate specificities and functionality of MutSa and MutSb we performed an in vitro MMR assay using three substrate constructs, GT mismatch, 1 and 2 nucleotide insertion/deletion loops (IDLs) in three different cell lines. RESULTS: Our results show that though MutSa alone seems to be responsible for GT and IDL1 repair, MutSa and MutSb indeed have functional redundancy in IDL2 repair and in contrast with earlier studies, MutSb seems to exceed MutSa. CONCLUSION: The finding is clinically relevant because the strong role of MutSb in IDL2 repair indicates MSH3 deficiency in tumours with low dinucleotide and no mononucleotide repeat instability.

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“…The MSH2/6 dimer has been suggested to recognize single base-base mismatches and small loops of one to three unpaired nucleotides, whereas the MSH2/3 heterodimer is believed to predominantly recognize loops of two to five nucleotides. 20,21 The requirement for MMR deficiency imposes a severe restriction to the applicability of oligo targeting for the generation of mutant cell lines and mouse strains. Owing to the mutator phenotype of MMR-deficient cells, numerous inadvertent mutations may accumulate on top of the desired one, which could interfere with the viability and phenotype of cells.…”

Section: Introductionmentioning

confidence: 99%

Effective oligonucleotide-mediated gene disruption in ES cells lacking the mismatch repair protein MSH3

et al. 2006

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We have previously demonstrated that site-specific insertion, deletion or substitution of one or two nucleotides in mouse embryonic stem cells (ES cells) by single-stranded deoxyribo-oligonucleotides is several hundred-fold suppressed by DNA mismatch repair (MMR) activity. Here, we have investigated whether compound mismatches and larger insertions escape detection by the MMR machinery and can be effectively introduced in MMR-proficient cells. We identified several compound mismatches that escaped detection by the MMR machinery to some extent, but could not define general rules predicting the efficacy of complex base-pair substitutions. In contrast, we found that fournucleotide insertions were largely subject to suppression by the MSH2/MSH3 branch of MMR and could be effectively introduced in Msh3-deficient cells. As these cells have no overt mutator phenotype and Msh3-deficient mice do not develop cancer, Msh3-deficient ES cells can be used for oligonucleotide-mediated gene disruption. As an example, we present disruption of the Fanconi anemia gene Fancf. Gene Therapy (2006) 13, 686-694.

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Isolation of MutSβ from Human Cells and Comparison of the Mismatch Repair Specificities of MutSβ and MutSα

Cited by 366 publications

References 42 publications

Somatic mutation of hPMS2 as a possible cause of sporadic human colon cancer with microsatellite instability

Somatic mutation of hPMS2 as a possible cause of sporadic human colon cancer with microsatellite instability

MutSβ exceeds MutSα in dinucleotide loop repair

Effective oligonucleotide-mediated gene disruption in ES cells lacking the mismatch repair protein MSH3

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